Merge pull request #3984 from poettering/refcnt

permit bus clients to pin units to avoid automatic GC

26 files changed, 1162 insertions, 255 deletions

diff --git a/src/core/cgroup.c b/src/core/cgroup.c
index 086cd7a789..20f9f9fc7e 100644
--- a/src/core/cgroup.c
+++ b/src/core/cgroup.c
@@ -1524,6 +1524,8 @@ void unit_prune_cgroup(Unit *u) {
         if (!u->cgroup_path)
                 return;
 
+        (void) unit_get_cpu_usage(u, NULL); /* Cache the last CPU usage value before we destroy the cgroup */
+
         is_root_slice = unit_has_name(u, SPECIAL_ROOT_SLICE);
 
         r = cg_trim_everywhere(u->manager->cgroup_supported, u->cgroup_path, !is_root_slice);
@@ -2044,7 +2046,21 @@ int unit_get_cpu_usage(Unit *u, nsec_t *ret) {
         nsec_t ns;
         int r;
 
+        assert(u);
+
+        /* Retrieve the current CPU usage counter. This will subtract the CPU counter taken when the unit was
+         * started. If the cgroup has been removed already, returns the last cached value. To cache the value, simply
+         * call this function with a NULL return value. */
+
         r = unit_get_cpu_usage_raw(u, &ns);
+        if (r == -ENODATA && u->cpu_usage_last != NSEC_INFINITY) {
+                /* If we can't get the CPU usage anymore (because the cgroup was already removed, for example), use our
+                 * cached value. */
+
+                if (ret)
+                        *ret = u->cpu_usage_last;
+                return 0;
+        }
         if (r < 0)
                 return r;
 
@@ -2053,7 +2069,10 @@ int unit_get_cpu_usage(Unit *u, nsec_t *ret) {
         else
                 ns = 0;
 
-        *ret = ns;
+        u->cpu_usage_last = ns;
+        if (ret)
+                *ret = ns;
+
         return 0;
 }
 
@@ -2063,6 +2082,8 @@ int unit_reset_cpu_usage(Unit *u) {
 
         assert(u);
 
+        u->cpu_usage_last = NSEC_INFINITY;
+
         r = unit_get_cpu_usage_raw(u, &ns);
         if (r < 0) {
                 u->cpu_usage_base = 0;
diff --git a/src/core/dbus-manager.c b/src/core/dbus-manager.c
index ef05a75a8b..ea7ced2fd0 100644
--- a/src/core/dbus-manager.c
+++ b/src/core/dbus-manager.c
@@ -643,6 +643,54 @@ static int method_set_unit_properties(sd_bus_message *message, void *userdata, s
         return bus_unit_method_set_properties(message, u, error);
 }
 
+static int method_ref_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        const char *name;
+        Unit *u;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "s", &name);
+        if (r < 0)
+                return r;
+
+        r = manager_load_unit(m, name, NULL, error, &u);
+        if (r < 0)
+                return r;
+
+        r = bus_unit_check_load_state(u, error);
+        if (r < 0)
+                return r;
+
+        return bus_unit_method_ref(message, u, error);
+}
+
+static int method_unref_unit(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Manager *m = userdata;
+        const char *name;
+        Unit *u;
+        int r;
+
+        assert(message);
+        assert(m);
+
+        r = sd_bus_message_read(message, "s", &name);
+        if (r < 0)
+                return r;
+
+        r = manager_load_unit(m, name, NULL, error, &u);
+        if (r < 0)
+                return r;
+
+        r = bus_unit_check_load_state(u, error);
+        if (r < 0)
+                return r;
+
+        return bus_unit_method_unref(message, u, error);
+}
+
 static int reply_unit_info(sd_bus_message *reply, Unit *u) {
         _cleanup_free_ char *unit_path = NULL, *job_path = NULL;
         Unit *following;
@@ -781,6 +829,13 @@ static int transient_unit_from_message(
         if (r < 0)
                 return r;
 
+        /* If the client asked for it, automatically add a reference to this unit. */
+        if (u->bus_track_add) {
+                r = bus_unit_track_add_sender(u, message);
+                if (r < 0)
+                        return log_error_errno(r, "Failed to watch sender: %m");
+        }
+
         /* Now load the missing bits of the unit we just created */
         unit_add_to_load_queue(u);
         manager_dispatch_load_queue(m);
@@ -2211,6 +2266,8 @@ const sd_bus_vtable bus_manager_vtable[] = {
         SD_BUS_METHOD("KillUnit", "ssi", NULL, method_kill_unit, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("ResetFailedUnit", "s", NULL, method_reset_failed_unit, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("SetUnitProperties", "sba(sv)", NULL, method_set_unit_properties, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("RefUnit", "s", NULL, method_ref_unit, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("UnrefUnit", "s", NULL, method_unref_unit, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("StartTransientUnit", "ssa(sv)a(sa(sv))", "o", method_start_transient_unit, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetUnitProcesses", "s", "a(sus)", method_get_unit_processes, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("GetJob", "u", "o", method_get_job, SD_BUS_VTABLE_UNPRIVILEGED),
diff --git a/src/core/dbus-unit.c b/src/core/dbus-unit.c
index 89e56a2e51..1b86bdde43 100644
--- a/src/core/dbus-unit.c
+++ b/src/core/dbus-unit.c
@@ -418,6 +418,7 @@ static int bus_verify_manage_units_async_full(
                 const char *verb,
                 int capability,
                 const char *polkit_message,
+                bool interactive,
                 sd_bus_message *call,
                 sd_bus_error *error) {
 
@@ -433,7 +434,15 @@ static int bus_verify_manage_units_async_full(
                 details[7] = GETTEXT_PACKAGE;
         }
 
-        return bus_verify_polkit_async(call, capability, "org.freedesktop.systemd1.manage-units", details, false, UID_INVALID, &u->manager->polkit_registry, error);
+        return bus_verify_polkit_async(
+                        call,
+                        capability,
+                        "org.freedesktop.systemd1.manage-units",
+                        details,
+                        interactive,
+                        UID_INVALID,
+                        &u->manager->polkit_registry,
+                        error);
 }
 
 int bus_unit_method_start_generic(
@@ -486,6 +495,7 @@ int bus_unit_method_start_generic(
                         verb,
                         CAP_SYS_ADMIN,
                         job_type < _JOB_TYPE_MAX ? polkit_message_for_job[job_type] : NULL,
+                        true,
                         message,
                         error);
         if (r < 0)
@@ -558,6 +568,7 @@ int bus_unit_method_kill(sd_bus_message *message, void *userdata, sd_bus_error *
                         "kill",
                         CAP_KILL,
                         N_("Authentication is required to kill '$(unit)'."),
+                        true,
                         message,
                         error);
         if (r < 0)
@@ -588,6 +599,7 @@ int bus_unit_method_reset_failed(sd_bus_message *message, void *userdata, sd_bus
                         "reset-failed",
                         CAP_SYS_ADMIN,
                         N_("Authentication is required to reset the \"failed\" state of '$(unit)'."),
+                        true,
                         message,
                         error);
         if (r < 0)
@@ -620,6 +632,7 @@ int bus_unit_method_set_properties(sd_bus_message *message, void *userdata, sd_b
                         "set-property",
                         CAP_SYS_ADMIN,
                         N_("Authentication is required to set properties on '$(unit)'."),
+                        true,
                         message,
                         error);
         if (r < 0)
@@ -634,6 +647,53 @@ int bus_unit_method_set_properties(sd_bus_message *message, void *userdata, sd_b
         return sd_bus_reply_method_return(message, NULL);
 }
 
+int bus_unit_method_ref(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Unit *u = userdata;
+        int r;
+
+        assert(message);
+        assert(u);
+
+        r = mac_selinux_unit_access_check(u, message, "start", error);
+        if (r < 0)
+                return r;
+
+        r = bus_verify_manage_units_async_full(
+                        u,
+                        "ref",
+                        CAP_SYS_ADMIN,
+                        NULL,
+                        false,
+                        message,
+                        error);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return 1; /* No authorization for now, but the async polkit stuff will call us again when it has it */
+
+        r = bus_unit_track_add_sender(u, message);
+        if (r < 0)
+                return r;
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
+int bus_unit_method_unref(sd_bus_message *message, void *userdata, sd_bus_error *error) {
+        Unit *u = userdata;
+        int r;
+
+        assert(message);
+        assert(u);
+
+        r = bus_unit_track_remove_sender(u, message);
+        if (r == -EUNATCH)
+                return sd_bus_error_setf(error, BUS_ERROR_NOT_REFERENCED, "Unit has not been referenced yet.");
+        if (r < 0)
+                return r;
+
+        return sd_bus_reply_method_return(message, NULL);
+}
+
 const sd_bus_vtable bus_unit_vtable[] = {
         SD_BUS_VTABLE_START(0),
 
@@ -715,6 +775,8 @@ const sd_bus_vtable bus_unit_vtable[] = {
         SD_BUS_METHOD("Kill", "si", NULL, bus_unit_method_kill, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("ResetFailed", NULL, NULL, bus_unit_method_reset_failed, SD_BUS_VTABLE_UNPRIVILEGED),
         SD_BUS_METHOD("SetProperties", "ba(sv)", NULL, bus_unit_method_set_properties, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("Ref", NULL, NULL, bus_unit_method_ref, SD_BUS_VTABLE_UNPRIVILEGED),
+        SD_BUS_METHOD("Unref", NULL, NULL, bus_unit_method_unref, SD_BUS_VTABLE_UNPRIVILEGED),
 
         /* Obsolete properties or obsolete alias names */
         SD_BUS_PROPERTY("RequiresOverridable", "as", property_get_obsolete_dependencies, 0, SD_BUS_VTABLE_HIDDEN),
@@ -1318,6 +1380,29 @@ static int bus_unit_set_transient_property(
                         return r;
 
                 return 1;
+
+        } else if (streq(name, "AddRef")) {
+
+                int b;
+
+                /* Why is this called "AddRef" rather than just "Ref", or "Reference"? There's already a "Ref()" method
+                 * on the Unit interface, and it's probably not a good idea to expose a property and a method on the
+                 * same interface (well, strictly speaking AddRef isn't exposed as full property, we just read it for
+                 * transient units, but still). And "References" and "ReferencedBy" is already used as unit reference
+                 * dependency type, hence let's not confuse things with that.
+                 *
+                 * Note that we don't acually add the reference to the bus track. We do that only after the setup of
+                 * the transient unit is complete, so that setting this property multiple times in the same transient
+                 * unit creation call doesn't count as individual references. */
+
+                r = sd_bus_message_read(message, "b", &b);
+                if (r < 0)
+                        return r;
+
+                if (mode != UNIT_CHECK)
+                        u->bus_track_add = b;
+
+                return 1;
         }
 
         return 0;
@@ -1422,3 +1507,71 @@ int bus_unit_check_load_state(Unit *u, sd_bus_error *error) {
 
         return sd_bus_error_set_errnof(error, u->load_error, "Unit %s is not loaded properly: %m.", u->id);
 }
+
+static int bus_track_handler(sd_bus_track *t, void *userdata) {
+        Unit *u = userdata;
+
+        assert(t);
+        assert(u);
+
+        u->bus_track = sd_bus_track_unref(u->bus_track); /* make sure we aren't called again */
+
+        unit_add_to_gc_queue(u);
+        return 0;
+}
+
+static int allocate_bus_track(Unit *u) {
+        int r;
+
+        assert(u);
+
+        if (u->bus_track)
+                return 0;
+
+        r = sd_bus_track_new(u->manager->api_bus, &u->bus_track, bus_track_handler, u);
+        if (r < 0)
+                return r;
+
+        r = sd_bus_track_set_recursive(u->bus_track, true);
+        if (r < 0) {
+                u->bus_track = sd_bus_track_unref(u->bus_track);
+                return r;
+        }
+
+        return 0;
+}
+
+int bus_unit_track_add_name(Unit *u, const char *name) {
+        int r;
+
+        assert(u);
+
+        r = allocate_bus_track(u);
+        if (r < 0)
+                return r;
+
+        return sd_bus_track_add_name(u->bus_track, name);
+}
+
+int bus_unit_track_add_sender(Unit *u, sd_bus_message *m) {
+        int r;
+
+        assert(u);
+
+        r = allocate_bus_track(u);
+        if (r < 0)
+                return r;
+
+        return sd_bus_track_add_sender(u->bus_track, m);
+}
+
+int bus_unit_track_remove_sender(Unit *u, sd_bus_message *m) {
+        assert(u);
+
+        /* If we haven't allocated the bus track object yet, then there's definitely no reference taken yet, return an
+         * error */
+        if (!u->bus_track)
+                return -EUNATCH;
+
+        return sd_bus_track_remove_sender(u->bus_track, m);
+}
diff --git a/src/core/dbus-unit.h b/src/core/dbus-unit.h
index 4db88dbebc..b280de7a1d 100644
--- a/src/core/dbus-unit.h
+++ b/src/core/dbus-unit.h
@@ -33,9 +33,15 @@ int bus_unit_method_start_generic(sd_bus_message *message, Unit *u, JobType job_
 int bus_unit_method_kill(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_unit_method_reset_failed(sd_bus_message *message, void *userdata, sd_bus_error *error);
 
-int bus_unit_queue_job(sd_bus_message *message, Unit *u, JobType type, JobMode mode, bool reload_if_possible, sd_bus_error *error);
 int bus_unit_set_properties(Unit *u, sd_bus_message *message, UnitSetPropertiesMode mode, bool commit, sd_bus_error *error);
 int bus_unit_method_set_properties(sd_bus_message *message, void *userdata, sd_bus_error *error);
 int bus_unit_method_get_processes(sd_bus_message *message, void *userdata, sd_bus_error *error);
+int bus_unit_method_ref(sd_bus_message *message, void *userdata, sd_bus_error *error);
+int bus_unit_method_unref(sd_bus_message *message, void *userdata, sd_bus_error *error);
 
+int bus_unit_queue_job(sd_bus_message *message, Unit *u, JobType type, JobMode mode, bool reload_if_possible, sd_bus_error *error);
 int bus_unit_check_load_state(Unit *u, sd_bus_error *error);
+
+int bus_unit_track_add_name(Unit *u, const char *name);
+int bus_unit_track_add_sender(Unit *u, sd_bus_message *m);
+int bus_unit_track_remove_sender(Unit *u, sd_bus_message *m);
diff --git a/src/core/dbus.c b/src/core/dbus.c
index 3422a02d68..1e41a42aa6 100644
--- a/src/core/dbus.c
+++ b/src/core/dbus.c
@@ -1168,60 +1168,57 @@ int bus_foreach_bus(
         return ret;
 }
 
-void bus_track_serialize(sd_bus_track *t, FILE *f) {
+void bus_track_serialize(sd_bus_track *t, FILE *f, const char *prefix) {
         const char *n;
 
         assert(f);
+        assert(prefix);
 
-        for (n = sd_bus_track_first(t); n; n = sd_bus_track_next(t))
-                fprintf(f, "subscribed=%s\n", n);
-}
-
-int bus_track_deserialize_item(char ***l, const char *line) {
-        const char *e;
-        int r;
-
-        assert(l);
-        assert(line);
-
-        e = startswith(line, "subscribed=");
-        if (!e)
-                return 0;
+        for (n = sd_bus_track_first(t); n; n = sd_bus_track_next(t)) {
+                int c, j;
 
-        r = strv_extend(l, e);
-        if (r < 0)
-                return r;
+                c = sd_bus_track_count_name(t, n);
 
-        return 1;
+                for (j = 0; j < c; j++) {
+                        fputs(prefix, f);
+                        fputc('=', f);
+                        fputs(n, f);
+                        fputc('\n', f);
+                }
+        }
 }
 
-int bus_track_coldplug(Manager *m, sd_bus_track **t, char ***l) {
+int bus_track_coldplug(Manager *m, sd_bus_track **t, bool recursive, char **l) {
+        char **i;
         int r = 0;
 
         assert(m);
         assert(t);
-        assert(l);
-
-        if (!strv_isempty(*l) && m->api_bus) {
-                char **i;
 
-                if (!*t) {
-                        r = sd_bus_track_new(m->api_bus, t, NULL, NULL);
-                        if (r < 0)
-                                return r;
-                }
+        if (strv_isempty(l))
+                return 0;
 
-                r = 0;
-                STRV_FOREACH(i, *l) {
-                        int k;
+        if (!m->api_bus)
+                return 0;
 
-                        k = sd_bus_track_add_name(*t, *i);
-                        if (k < 0)
-                                r = k;
-                }
+        if (!*t) {
+                r = sd_bus_track_new(m->api_bus, t, NULL, NULL);
+                if (r < 0)
+                        return r;
         }
 
-        *l = strv_free(*l);
+        r = sd_bus_track_set_recursive(*t, recursive);
+        if (r < 0)
+                return r;
+
+        r = 0;
+        STRV_FOREACH(i, l) {
+                int k;
+
+                k = sd_bus_track_add_name(*t, *i);
+                if (k < 0)
+                        r = k;
+        }
 
         return r;
 }
diff --git a/src/core/dbus.h b/src/core/dbus.h
index 6baaffbd75..a092ed9d76 100644
--- a/src/core/dbus.h
+++ b/src/core/dbus.h
@@ -28,9 +28,8 @@ void bus_done(Manager *m);
 
 int bus_fdset_add_all(Manager *m, FDSet *fds);
 
-void bus_track_serialize(sd_bus_track *t, FILE *f);
-int bus_track_deserialize_item(char ***l, const char *line);
-int bus_track_coldplug(Manager *m, sd_bus_track **t, char ***l);
+void bus_track_serialize(sd_bus_track *t, FILE *f, const char *prefix);
+int bus_track_coldplug(Manager *m, sd_bus_track **t, bool recursive, char **l);
 
 int manager_sync_bus_names(Manager *m, sd_bus *bus);
 
diff --git a/src/core/job.c b/src/core/job.c
index 7557874d4d..7faf2ef686 100644
--- a/src/core/job.c
+++ b/src/core/job.c
@@ -997,7 +997,10 @@ char *job_dbus_path(Job *j) {
         return p;
 }
 
-int job_serialize(Job *j, FILE *f, FDSet *fds) {
+int job_serialize(Job *j, FILE *f) {
+        assert(j);
+        assert(f);
+
         fprintf(f, "job-id=%u\n", j->id);
         fprintf(f, "job-type=%s\n", job_type_to_string(j->type));
         fprintf(f, "job-state=%s\n", job_state_to_string(j->state));
@@ -1008,15 +1011,16 @@ int job_serialize(Job *j, FILE *f, FDSet *fds) {
         if (j->begin_usec > 0)
                 fprintf(f, "job-begin="USEC_FMT"\n", j->begin_usec);
 
-        bus_track_serialize(j->clients, f);
+        bus_track_serialize(j->clients, f, "subscribed");
 
         /* End marker */
         fputc('\n', f);
         return 0;
 }
 
-int job_deserialize(Job *j, FILE *f, FDSet *fds) {
+int job_deserialize(Job *j, FILE *f) {
         assert(j);
+        assert(f);
 
         for (;;) {
                 char line[LINE_MAX], *l, *v;
@@ -1106,7 +1110,7 @@ int job_deserialize(Job *j, FILE *f, FDSet *fds) {
                 } else if (streq(l, "subscribed")) {
 
                         if (strv_extend(&j->deserialized_clients, v) < 0)
-                                return log_oom();
+                                log_oom();
                 }
         }
 }
@@ -1118,9 +1122,8 @@ int job_coldplug(Job *j) {
 
         /* After deserialization is complete and the bus connection
          * set up again, let's start watching our subscribers again */
-        r = bus_track_coldplug(j->manager, &j->clients, &j->deserialized_clients);
-        if (r < 0)
-                return r;
+        (void) bus_track_coldplug(j->manager, &j->clients, false, j->deserialized_clients);
+        j->deserialized_clients = strv_free(j->deserialized_clients);
 
         if (j->state == JOB_WAITING)
                 job_add_to_run_queue(j);
diff --git a/src/core/job.h b/src/core/job.h
index d359e8bb3e..85368f0d30 100644
--- a/src/core/job.h
+++ b/src/core/job.h
@@ -177,8 +177,8 @@ Job* job_install(Job *j);
 int job_install_deserialized(Job *j);
 void job_uninstall(Job *j);
 void job_dump(Job *j, FILE*f, const char *prefix);
-int job_serialize(Job *j, FILE *f, FDSet *fds);
-int job_deserialize(Job *j, FILE *f, FDSet *fds);
+int job_serialize(Job *j, FILE *f);
+int job_deserialize(Job *j, FILE *f);
 int job_coldplug(Job *j);
 
 JobDependency* job_dependency_new(Job *subject, Job *object, bool matters, bool conflicts);
diff --git a/src/core/manager.c b/src/core/manager.c
index 7576d038a2..b58f68fa7a 100644
--- a/src/core/manager.c
+++ b/src/core/manager.c
@@ -1287,10 +1287,11 @@ int manager_startup(Manager *m, FILE *serialization, FDSet *fds) {
         if (q < 0 && r == 0)
                 r = q;
 
-        /* We might have deserialized the kdbus control fd, but if we
-         * didn't, then let's create the bus now. */
-        manager_connect_bus(m, !!serialization);
-        bus_track_coldplug(m, &m->subscribed, &m->deserialized_subscribed);
+        /* We might have deserialized the kdbus control fd, but if we didn't, then let's create the bus now. */
+        (void) manager_connect_bus(m, !!serialization);
+
+        (void) bus_track_coldplug(m, &m->subscribed, false, m->deserialized_subscribed);
+        m->deserialized_subscribed = strv_free(m->deserialized_subscribed);
 
         /* Third, fire things up! */
         manager_coldplug(m);
@@ -2490,7 +2491,7 @@ int manager_serialize(Manager *m, FILE *f, FDSet *fds, bool switching_root) {
                 fprintf(f, "kdbus-fd=%i\n", copy);
         }
 
-        bus_track_serialize(m->subscribed, f);
+        bus_track_serialize(m->subscribed, f, "subscribed");
 
         r = dynamic_user_serialize(m, f, fds);
         if (r < 0)
@@ -2693,15 +2694,13 @@ int manager_deserialize(Manager *m, FILE *f, FDSet *fds) {
                         manager_deserialize_uid_refs_one(m, l + 16);
                 else if (startswith(l, "destroy-ipc-gid="))
                         manager_deserialize_gid_refs_one(m, l + 16);
-                else {
-                        int k;
-
-                        k = bus_track_deserialize_item(&m->deserialized_subscribed, l);
-                        if (k < 0)
-                                log_debug_errno(k, "Failed to deserialize bus tracker object: %m");
-                        else if (k == 0)
-                                log_debug("Unknown serialization item '%s'", l);
-                }
+                else if (startswith(l, "subscribed=")) {
+
+                        if (strv_extend(&m->deserialized_subscribed, l+11) < 0)
+                                log_oom();
+
+                } else
+                        log_debug("Unknown serialization item '%s'", l);
         }
 
         for (;;) {
diff --git a/src/core/org.freedesktop.systemd1.conf b/src/core/org.freedesktop.systemd1.conf
index 14f6aec029..647e5f736c 100644
--- a/src/core/org.freedesktop.systemd1.conf
+++ b/src/core/org.freedesktop.systemd1.conf
@@ -184,6 +184,14 @@
 
                 <allow send_destination="org.freedesktop.systemd1"
                        send_interface="org.freedesktop.systemd1.Manager"
+                       send_member="RefUnit"/>
+
+                <allow send_destination="org.freedesktop.systemd1"
+                       send_interface="org.freedesktop.systemd1.Manager"
+                       send_member="UnrefUnit"/>
+
+                <allow send_destination="org.freedesktop.systemd1"
+                       send_interface="org.freedesktop.systemd1.Manager"
                        send_member="EnableUnitFiles"/>
 
                 <allow send_destination="org.freedesktop.systemd1"
diff --git a/src/core/unit.c b/src/core/unit.c
index c58c501bc3..de22f657c6 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -102,6 +102,7 @@ Unit *unit_new(Manager *m, size_t size) {
         u->job_timeout = USEC_INFINITY;
         u->ref_uid = UID_INVALID;
         u->ref_gid = GID_INVALID;
+        u->cpu_usage_last = NSEC_INFINITY;
 
         RATELIMIT_INIT(u->start_limit, m->default_start_limit_interval, m->default_start_limit_burst);
         RATELIMIT_INIT(u->auto_stop_ratelimit, 10 * USEC_PER_SEC, 16);
@@ -113,7 +114,7 @@ bool unit_has_name(Unit *u, const char *name) {
         assert(u);
         assert(name);
 
-        return !!set_get(u->names, (char*) name);
+        return set_contains(u->names, (char*) name);
 }
 
 static void unit_init(Unit *u) {
@@ -329,6 +330,9 @@ bool unit_check_gc(Unit *u) {
         if (u->refs)
                 return true;
 
+        if (sd_bus_track_count(u->bus_track) > 0)
+                return true;
+
         if (UNIT_VTABLE(u)->check_gc)
                 if (UNIT_VTABLE(u)->check_gc(u))
                         return true;
@@ -509,6 +513,9 @@ void unit_free(Unit *u) {
 
         sd_bus_slot_unref(u->match_bus_slot);
 
+        sd_bus_track_unref(u->bus_track);
+        u->deserialized_refs = strv_free(u->deserialized_refs);
+
         unit_free_requires_mounts_for(u);
 
         SET_FOREACH(t, u->names, i)
@@ -897,6 +904,7 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
         Unit *following;
         _cleanup_set_free_ Set *following_set = NULL;
         int r;
+        const char *n;
 
         assert(u);
         assert(u->type >= 0);
@@ -1038,6 +1046,8 @@ void unit_dump(Unit *u, FILE *f, const char *prefix) {
         else if (u->load_state == UNIT_ERROR)
                 fprintf(f, "%s\tLoad Error Code: %s\n", prefix, strerror(-u->load_error));
 
+        for (n = sd_bus_track_first(u->bus_track); n; n = sd_bus_track_next(u->bus_track))
+                fprintf(f, "%s\tBus Ref: %s\n", prefix, n);
 
         if (u->job)
                 job_dump(u->job, f, prefix2);
@@ -2611,7 +2621,10 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
                 unit_serialize_item(u, f, "assert-result", yes_no(u->assert_result));
 
         unit_serialize_item(u, f, "transient", yes_no(u->transient));
+
         unit_serialize_item_format(u, f, "cpu-usage-base", "%" PRIu64, u->cpu_usage_base);
+        if (u->cpu_usage_last != NSEC_INFINITY)
+                unit_serialize_item_format(u, f, "cpu-usage-last", "%" PRIu64, u->cpu_usage_last);
 
         if (u->cgroup_path)
                 unit_serialize_item(u, f, "cgroup", u->cgroup_path);
@@ -2622,15 +2635,17 @@ int unit_serialize(Unit *u, FILE *f, FDSet *fds, bool serialize_jobs) {
         if (gid_is_valid(u->ref_gid))
                 unit_serialize_item_format(u, f, "ref-gid", GID_FMT, u->ref_gid);
 
+        bus_track_serialize(u->bus_track, f, "ref");
+
         if (serialize_jobs) {
                 if (u->job) {
                         fprintf(f, "job\n");
-                        job_serialize(u->job, f, fds);
+                        job_serialize(u->job, f);
                 }
 
                 if (u->nop_job) {
                         fprintf(f, "job\n");
-                        job_serialize(u->nop_job, f, fds);
+                        job_serialize(u->nop_job, f);
                 }
         }
 
@@ -2760,7 +2775,7 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                                 if (!j)
                                         return log_oom();
 
-                                r = job_deserialize(j, f, fds);
+                                r = job_deserialize(j, f);
                                 if (r < 0) {
                                         job_free(j);
                                         return r;
@@ -2832,11 +2847,19 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
 
                         continue;
 
-                } else if (streq(l, "cpu-usage-base") || streq(l, "cpuacct-usage-base")) {
+                } else if (STR_IN_SET(l, "cpu-usage-base", "cpuacct-usage-base")) {
 
                         r = safe_atou64(v, &u->cpu_usage_base);
                         if (r < 0)
-                                log_unit_debug(u, "Failed to parse CPU usage %s, ignoring.", v);
+                                log_unit_debug(u, "Failed to parse CPU usage base %s, ignoring.", v);
+
+                        continue;
+
+                } else if (streq(l, "cpu-usage-last")) {
+
+                        r = safe_atou64(v, &u->cpu_usage_last);
+                        if (r < 0)
+                                log_unit_debug(u, "Failed to read CPU usage last %s, ignoring.", v);
 
                         continue;
 
@@ -2880,6 +2903,12 @@ int unit_deserialize(Unit *u, FILE *f, FDSet *fds) {
                         else
                                 unit_ref_uid_gid(u, UID_INVALID, gid);
 
+                } else if (streq(l, "ref")) {
+
+                        r = strv_extend(&u->deserialized_refs, v);
+                        if (r < 0)
+                                log_oom();
+
                         continue;
                 }
 
@@ -2955,7 +2984,8 @@ int unit_add_node_link(Unit *u, const char *what, bool wants, UnitDependency dep
 }
 
 int unit_coldplug(Unit *u) {
-        int r = 0, q = 0;
+        int r = 0, q;
+        char **i;
 
         assert(u);
 
@@ -2966,18 +2996,26 @@ int unit_coldplug(Unit *u) {
 
         u->coldplugged = true;
 
-        if (UNIT_VTABLE(u)->coldplug)
-                r = UNIT_VTABLE(u)->coldplug(u);
+        STRV_FOREACH(i, u->deserialized_refs) {
+                q = bus_unit_track_add_name(u, *i);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
+        u->deserialized_refs = strv_free(u->deserialized_refs);
 
-        if (u->job)
-                q = job_coldplug(u->job);
+        if (UNIT_VTABLE(u)->coldplug) {
+                q = UNIT_VTABLE(u)->coldplug(u);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
 
-        if (r < 0)
-                return r;
-        if (q < 0)
-                return q;
+        if (u->job) {
+                q = job_coldplug(u->job);
+                if (q < 0 && r >= 0)
+                        r = q;
+        }
 
-        return 0;
+        return r;
 }
 
 static bool fragment_mtime_newer(const char *path, usec_t mtime) {
diff --git a/src/core/unit.h b/src/core/unit.h
index f7a65782f1..3584c16d8c 100644
--- a/src/core/unit.h
+++ b/src/core/unit.h
@@ -108,6 +108,10 @@ struct Unit {
         /* The slot used for watching NameOwnerChanged signals */
         sd_bus_slot *match_bus_slot;
 
+        /* References to this unit from clients */
+        sd_bus_track *bus_track;
+        char **deserialized_refs;
+
         /* Job timeout and action to take */
         usec_t job_timeout;
         FailureAction job_timeout_action;
@@ -190,6 +194,7 @@ struct Unit {
 
         /* Where the cpu.stat or cpuacct.usage was at the time the unit was started */
         nsec_t cpu_usage_base;
+        nsec_t cpu_usage_last; /* the most recently read value */
 
         /* Counterparts in the cgroup filesystem */
         char *cgroup_path;
@@ -247,6 +252,9 @@ struct Unit {
 
         /* Did we already invoke unit_coldplug() for this unit? */
         bool coldplugged:1;
+
+        /* For transient units: whether to add a bus track reference after creating the unit */
+        bool bus_track_add:1;
 };
 
 struct UnitStatusMessageFormats {
diff --git a/src/libsystemd/libsystemd.sym b/src/libsystemd/libsystemd.sym
index 542254295c..70ea347361 100644
--- a/src/libsystemd/libsystemd.sym
+++ b/src/libsystemd/libsystemd.sym
@@ -500,3 +500,13 @@ LIBSYSTEMD_231 {
 global:
         sd_event_get_iteration;
 } LIBSYSTEMD_230;
+
+LIBSYSTEMD_232 {
+global:
+        sd_bus_track_set_recursive;
+        sd_bus_track_get_recursive;
+        sd_bus_track_count_name;
+        sd_bus_track_count_sender;
+        sd_bus_set_exit_on_disconnect;
+        sd_bus_get_exit_on_disconnect;
+} LIBSYSTEMD_231;
diff --git a/src/libsystemd/sd-bus/bus-common-errors.c b/src/libsystemd/sd-bus/bus-common-errors.c
index 32be3cdc38..a69193aa32 100644
--- a/src/libsystemd/sd-bus/bus-common-errors.c
+++ b/src/libsystemd/sd-bus/bus-common-errors.c
@@ -45,6 +45,7 @@ BUS_ERROR_MAP_ELF_REGISTER const sd_bus_error_map bus_common_errors[] = {
         SD_BUS_ERROR_MAP(BUS_ERROR_SHUTTING_DOWN,                ECANCELED),
         SD_BUS_ERROR_MAP(BUS_ERROR_SCOPE_NOT_RUNNING,            EHOSTDOWN),
         SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_DYNAMIC_USER,         ESRCH),
+        SD_BUS_ERROR_MAP(BUS_ERROR_NOT_REFERENCED,               EUNATCH),
 
         SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_MACHINE,              ENXIO),
         SD_BUS_ERROR_MAP(BUS_ERROR_NO_SUCH_IMAGE,                ENOENT),
diff --git a/src/libsystemd/sd-bus/bus-common-errors.h b/src/libsystemd/sd-bus/bus-common-errors.h
index befb6fbfe0..5df21c8926 100644
--- a/src/libsystemd/sd-bus/bus-common-errors.h
+++ b/src/libsystemd/sd-bus/bus-common-errors.h
@@ -41,6 +41,7 @@
 #define BUS_ERROR_SHUTTING_DOWN "org.freedesktop.systemd1.ShuttingDown"
 #define BUS_ERROR_SCOPE_NOT_RUNNING "org.freedesktop.systemd1.ScopeNotRunning"
 #define BUS_ERROR_NO_SUCH_DYNAMIC_USER "org.freedesktop.systemd1.NoSuchDynamicUser"
+#define BUS_ERROR_NOT_REFERENCED "org.freedesktop.systemd1.NotReferenced"
 
 #define BUS_ERROR_NO_SUCH_MACHINE "org.freedesktop.machine1.NoSuchMachine"
 #define BUS_ERROR_NO_SUCH_IMAGE "org.freedesktop.machine1.NoSuchImage"
diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index 216d9f62bc..2608f5469c 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -209,6 +209,9 @@ struct sd_bus {
         bool is_system:1;
         bool is_user:1;
         bool allow_interactive_authorization:1;
+        bool exit_on_disconnect:1;
+        bool exited:1;
+        bool exit_triggered:1;
 
         int use_memfd;
 
@@ -320,6 +323,7 @@ struct sd_bus {
         sd_bus_track *track_queue;
 
         LIST_HEAD(sd_bus_slot, slots);
+        LIST_HEAD(sd_bus_track, tracks);
 };
 
 #define BUS_DEFAULT_TIMEOUT ((usec_t) (25 * USEC_PER_SEC))
diff --git a/src/libsystemd/sd-bus/bus-track.c b/src/libsystemd/sd-bus/bus-track.c
index 1f436fe560..00e93a215f 100644
--- a/src/libsystemd/sd-bus/bus-track.c
+++ b/src/libsystemd/sd-bus/bus-track.c
@@ -24,16 +24,27 @@
 #include "bus-track.h"
 #include "bus-util.h"
 
+struct track_item {
+        unsigned n_ref;
+        char *name;
+        sd_bus_slot *slot;
+};
+
 struct sd_bus_track {
         unsigned n_ref;
+        unsigned n_adding; /* are we in the process of adding a new name? */
         sd_bus *bus;
         sd_bus_track_handler_t handler;
         void *userdata;
         Hashmap *names;
         LIST_FIELDS(sd_bus_track, queue);
         Iterator iterator;
-        bool in_queue;
-        bool modified;
+        bool in_list:1;    /* In bus->tracks? */
+        bool in_queue:1;   /* In bus->track_queue? */
+        bool modified:1;
+        bool recursive:1;
+
+        LIST_FIELDS(sd_bus_track, tracks);
 };
 
 #define MATCH_PREFIX                                        \
@@ -56,15 +67,47 @@ struct sd_bus_track {
                 _x;                                                     \
         })
 
+static struct track_item* track_item_free(struct track_item *i) {
+
+        if (!i)
+                return NULL;
+
+        sd_bus_slot_unref(i->slot);
+        free(i->name);
+        free(i);
+
+        return NULL;
+}
+
+DEFINE_TRIVIAL_CLEANUP_FUNC(struct track_item*, track_item_free);
+
 static void bus_track_add_to_queue(sd_bus_track *track) {
         assert(track);
 
+        /* Adds the bus track object to the queue of objects we should dispatch next, subject to a number of
+         * conditions. */
+
+        /* Already in the queue? */
         if (track->in_queue)
                 return;
 
+        /* if we are currently in the process of adding a new name, then let's not enqueue this just yet, let's wait
+         * until the addition is complete. */
+        if (track->n_adding > 0)
+                return;
+
+        /* still referenced? */
+        if (hashmap_size(track->names) > 0)
+                return;
+
+        /* Nothing to call? */
         if (!track->handler)
                 return;
 
+        /* Already closed? */
+        if (!track->in_list)
+                return;
+
         LIST_PREPEND(queue, track->bus->track_queue, track);
         track->in_queue = true;
 }
@@ -79,6 +122,24 @@ static void bus_track_remove_from_queue(sd_bus_track *track) {
         track->in_queue = false;
 }
 
+static int bus_track_remove_name_fully(sd_bus_track *track, const char *name) {
+        struct track_item *i;
+
+        assert(track);
+        assert(name);
+
+        i = hashmap_remove(track->names, name);
+        if (!i)
+                return 0;
+
+        track_item_free(i);
+
+        bus_track_add_to_queue(track);
+
+        track->modified = true;
+        return 1;
+}
+
 _public_ int sd_bus_track_new(
                 sd_bus *bus,
                 sd_bus_track **track,
@@ -102,6 +163,9 @@ _public_ int sd_bus_track_new(
         t->userdata = userdata;
         t->bus = sd_bus_ref(bus);
 
+        LIST_PREPEND(tracks, bus->tracks, t);
+        t->in_list = true;
+
         bus_track_add_to_queue(t);
 
         *track = t;
@@ -121,7 +185,7 @@ _public_ sd_bus_track* sd_bus_track_ref(sd_bus_track *track) {
 }
 
 _public_ sd_bus_track* sd_bus_track_unref(sd_bus_track *track) {
-        const char *n;
+        struct track_item *i;
 
         if (!track)
                 return NULL;
@@ -133,8 +197,11 @@ _public_ sd_bus_track* sd_bus_track_unref(sd_bus_track *track) {
                 return NULL;
         }
 
-        while ((n = hashmap_first_key(track->names)))
-                sd_bus_track_remove_name(track, n);
+        while ((i = hashmap_steal_first(track->names)))
+                track_item_free(i);
+
+        if (track->in_list)
+                LIST_REMOVE(tracks, track->bus->tracks, track);
 
         bus_track_remove_from_queue(track);
         hashmap_free(track->names);
@@ -156,49 +223,76 @@ static int on_name_owner_changed(sd_bus_message *message, void *userdata, sd_bus
         if (r < 0)
                 return 0;
 
-        sd_bus_track_remove_name(track, name);
+        bus_track_remove_name_fully(track, name);
         return 0;
 }
 
 _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
-        _cleanup_(sd_bus_slot_unrefp) sd_bus_slot *slot = NULL;
-        _cleanup_free_ char *n = NULL;
+        _cleanup_(track_item_freep) struct track_item *n = NULL;
+        struct track_item *i;
         const char *match;
         int r;
 
         assert_return(track, -EINVAL);
         assert_return(service_name_is_valid(name), -EINVAL);
 
+        i = hashmap_get(track->names, name);
+        if (i) {
+                if (track->recursive) {
+                        unsigned k = track->n_ref + 1;
+
+                        if (k < track->n_ref) /* Check for overflow */
+                                return -EOVERFLOW;
+
+                        track->n_ref = k;
+                }
+
+                bus_track_remove_from_queue(track);
+                return 0;
+        }
+
         r = hashmap_ensure_allocated(&track->names, &string_hash_ops);
         if (r < 0)
                 return r;
 
-        n = strdup(name);
+        n = new0(struct track_item, 1);
         if (!n)
                 return -ENOMEM;
+        n->name = strdup(name);
+        if (!n->name)
+                return -ENOMEM;
 
         /* First, subscribe to this name */
-        match = MATCH_FOR_NAME(n);
-        r = sd_bus_add_match(track->bus, &slot, match, on_name_owner_changed, track);
-        if (r < 0)
+        match = MATCH_FOR_NAME(name);
+
+        bus_track_remove_from_queue(track); /* don't dispatch this while we work in it */
+
+        track->n_adding++; /* make sure we aren't dispatched while we synchronously add this match */
+        r = sd_bus_add_match(track->bus, &n->slot, match, on_name_owner_changed, track);
+        track->n_adding--;
+        if (r < 0) {
+                bus_track_add_to_queue(track);
                 return r;
+        }
 
-        r = hashmap_put(track->names, n, slot);
-        if (r == -EEXIST)
-                return 0;
-        if (r < 0)
+        r = hashmap_put(track->names, n->name, n);
+        if (r < 0) {
+                bus_track_add_to_queue(track);
                 return r;
+        }
 
-        /* Second, check if it is currently existing, or maybe
-         * doesn't, or maybe disappeared already. */
-        r = sd_bus_get_name_creds(track->bus, n, 0, NULL);
+        /* Second, check if it is currently existing, or maybe doesn't, or maybe disappeared already. */
+        track->n_adding++; /* again, make sure this isn't dispatch while we are working in it */
+        r = sd_bus_get_name_creds(track->bus, name, 0, NULL);
+        track->n_adding--;
         if (r < 0) {
-                hashmap_remove(track->names, n);
+                hashmap_remove(track->names, name);
+                bus_track_add_to_queue(track);
                 return r;
         }
 
+        n->n_ref = 1;
         n = NULL;
-        slot = NULL;
 
         bus_track_remove_from_queue(track);
         track->modified = true;
@@ -207,37 +301,48 @@ _public_ int sd_bus_track_add_name(sd_bus_track *track, const char *name) {
 }
 
 _public_ int sd_bus_track_remove_name(sd_bus_track *track, const char *name) {
-        _cleanup_(sd_bus_slot_unrefp) sd_bus_slot *slot = NULL;
-        _cleanup_free_ char *n = NULL;
+        struct track_item *i;
 
         assert_return(name, -EINVAL);
 
-        if (!track)
+        if (!track) /* Treat a NULL track object as an empty track object */
                 return 0;
 
-        slot = hashmap_remove2(track->names, (char*) name, (void**) &n);
-        if (!slot)
-                return 0;
+        if (!track->recursive)
+                return bus_track_remove_name_fully(track, name);
 
-        if (hashmap_isempty(track->names))
-                bus_track_add_to_queue(track);
+        i = hashmap_get(track->names, name);
+        if (!i)
+                return -EUNATCH;
+        if (i->n_ref <= 0)
+                return -EUNATCH;
 
-        track->modified = true;
+        i->n_ref--;
+
+        if (i->n_ref <= 0)
+                return bus_track_remove_name_fully(track, name);
 
         return 1;
 }
 
 _public_ unsigned sd_bus_track_count(sd_bus_track *track) {
-        if (!track)
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
                 return 0;
 
+        /* This signature really should have returned an int, so that we can propagate errors. But well, ... Also, note
+         * that this returns the number of names being watched, and multiple references to the same name are not
+         * counted. */
+
         return hashmap_size(track->names);
 }
 
 _public_ const char* sd_bus_track_contains(sd_bus_track *track, const char *name) {
-        assert_return(track, NULL);
         assert_return(name, NULL);
 
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return NULL;
+
         return hashmap_get(track->names, (void*) name) ? name : NULL;
 }
 
@@ -273,6 +378,9 @@ _public_ int sd_bus_track_add_sender(sd_bus_track *track, sd_bus_message *m) {
         assert_return(track, -EINVAL);
         assert_return(m, -EINVAL);
 
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
         sender = sd_bus_message_get_sender(m);
         if (!sender)
                 return -EINVAL;
@@ -283,9 +391,14 @@ _public_ int sd_bus_track_add_sender(sd_bus_track *track, sd_bus_message *m) {
 _public_ int sd_bus_track_remove_sender(sd_bus_track *track, sd_bus_message *m) {
         const char *sender;
 
-        assert_return(track, -EINVAL);
         assert_return(m, -EINVAL);
 
+        if (!track) /* Treat a NULL track object as an empty track object */
+                return 0;
+
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
         sender = sd_bus_message_get_sender(m);
         if (!sender)
                 return -EINVAL;
@@ -303,7 +416,6 @@ void bus_track_dispatch(sd_bus_track *track) {
         int r;
 
         assert(track);
-        assert(track->in_queue);
         assert(track->handler);
 
         bus_track_remove_from_queue(track);
@@ -319,6 +431,34 @@ void bus_track_dispatch(sd_bus_track *track) {
         sd_bus_track_unref(track);
 }
 
+void bus_track_close(sd_bus_track *track) {
+        struct track_item *i;
+
+        assert(track);
+
+        /* Called whenever our bus connected is closed. If so, and our track object is non-empty, dispatch it
+         * immediately, as we are closing now, but first flush out all names. */
+
+        if (!track->in_list)
+                return; /* We already closed this one, don't close it again. */
+
+        /* Remember that this one is closed now */
+        LIST_REMOVE(tracks, track->bus->tracks, track);
+        track->in_list = false;
+
+        /* If there's no name in this one anyway, we don't have to dispatch */
+        if (hashmap_isempty(track->names))
+                return;
+
+        /* Let's flush out all names */
+        while ((i = hashmap_steal_first(track->names)))
+                track_item_free(i);
+
+        /* Invoke handler */
+        if (track->handler)
+                bus_track_dispatch(track);
+}
+
 _public_ void *sd_bus_track_get_userdata(sd_bus_track *track) {
         assert_return(track, NULL);
 
@@ -335,3 +475,55 @@ _public_ void *sd_bus_track_set_userdata(sd_bus_track *track, void *userdata) {
 
         return ret;
 }
+
+_public_ int sd_bus_track_set_recursive(sd_bus_track *track, int b) {
+        assert_return(track, -EINVAL);
+
+        if (track->recursive == !!b)
+                return 0;
+
+        if (!hashmap_isempty(track->names))
+                return -EBUSY;
+
+        track->recursive = b;
+        return 0;
+}
+
+_public_ int sd_bus_track_get_recursive(sd_bus_track *track) {
+        assert_return(track, -EINVAL);
+
+        return track->recursive;
+}
+
+_public_ int sd_bus_track_count_sender(sd_bus_track *track, sd_bus_message *m) {
+        const char *sender;
+
+        assert_return(m, -EINVAL);
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return 0;
+
+        if (sd_bus_message_get_bus(m) != track->bus)
+                return -EINVAL;
+
+        sender = sd_bus_message_get_sender(m);
+        if (!sender)
+                return -EINVAL;
+
+        return sd_bus_track_count_name(track, sender);
+}
+
+_public_ int sd_bus_track_count_name(sd_bus_track *track, const char *name) {
+        struct track_item *i;
+
+        assert_return(service_name_is_valid(name), -EINVAL);
+
+        if (!track) /* Let's consider a NULL object equivalent to an empty object */
+                return 0;
+
+        i = hashmap_get(track->names, name);
+        if (!i)
+                return 0;
+
+        return i->n_ref;
+}
diff --git a/src/libsystemd/sd-bus/bus-track.h b/src/libsystemd/sd-bus/bus-track.h
index 7d93a727d6..26bd05f5c7 100644
--- a/src/libsystemd/sd-bus/bus-track.h
+++ b/src/libsystemd/sd-bus/bus-track.h
@@ -20,3 +20,4 @@
 ***/
 
 void bus_track_dispatch(sd_bus_track *track);
+void bus_track_close(sd_bus_track *track);
diff --git a/src/libsystemd/sd-bus/sd-bus.c b/src/libsystemd/sd-bus/sd-bus.c
index ed5f94e136..d746348544 100644
--- a/src/libsystemd/sd-bus/sd-bus.c
+++ b/src/libsystemd/sd-bus/sd-bus.c
@@ -107,6 +107,7 @@ static void bus_free(sd_bus *b) {
 
         assert(b);
         assert(!b->track_queue);
+        assert(!b->tracks);
 
         b->state = BUS_CLOSED;
 
@@ -2640,62 +2641,101 @@ null_message:
         return r;
 }
 
-static int process_closing(sd_bus *bus, sd_bus_message **ret) {
+static int bus_exit_now(sd_bus *bus) {
+        assert(bus);
+
+        /* Exit due to close, if this is requested. If this is bus object is attached to an event source, invokes
+         * sd_event_exit(), otherwise invokes libc exit(). */
+
+        if (bus->exited) /* did we already exit? */
+                return 0;
+        if (!bus->exit_triggered) /* was the exit condition triggered? */
+                return 0;
+        if (!bus->exit_on_disconnect) /* Shall we actually exit on disconnection? */
+                return 0;
+
+        bus->exited = true; /* never exit more than once */
+
+        log_debug("Bus connection disconnected, exiting.");
+
+        if (bus->event)
+                return sd_event_exit(bus->event, EXIT_FAILURE);
+        else
+                exit(EXIT_FAILURE);
+
+        assert_not_reached("exit() didn't exit?");
+}
+
+static int process_closing_reply_callback(sd_bus *bus, struct reply_callback *c) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
-        struct reply_callback *c;
+        sd_bus_slot *slot;
         int r;
 
         assert(bus);
-        assert(bus->state == BUS_CLOSING);
+        assert(c);
 
-        c = ordered_hashmap_first(bus->reply_callbacks);
-        if (c) {
-                _cleanup_(sd_bus_error_free) sd_bus_error error_buffer = SD_BUS_ERROR_NULL;
-                sd_bus_slot *slot;
+        r = bus_message_new_synthetic_error(
+                        bus,
+                        c->cookie,
+                        &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Connection terminated"),
+                        &m);
+        if (r < 0)
+                return r;
 
-                /* First, fail all outstanding method calls */
-                r = bus_message_new_synthetic_error(
-                                bus,
-                                c->cookie,
-                                &SD_BUS_ERROR_MAKE_CONST(SD_BUS_ERROR_NO_REPLY, "Connection terminated"),
-                                &m);
-                if (r < 0)
-                        return r;
+        r = bus_seal_synthetic_message(bus, m);
+        if (r < 0)
+                return r;
 
-                r = bus_seal_synthetic_message(bus, m);
-                if (r < 0)
-                        return r;
+        if (c->timeout != 0) {
+                prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
+                c->timeout = 0;
+        }
 
-                if (c->timeout != 0) {
-                        prioq_remove(bus->reply_callbacks_prioq, c, &c->prioq_idx);
-                        c->timeout = 0;
-                }
+        ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
+        c->cookie = 0;
 
-                ordered_hashmap_remove(bus->reply_callbacks, &c->cookie);
-                c->cookie = 0;
+        slot = container_of(c, sd_bus_slot, reply_callback);
 
-                slot = container_of(c, sd_bus_slot, reply_callback);
+        bus->iteration_counter++;
 
-                bus->iteration_counter++;
+        bus->current_message = m;
+        bus->current_slot = sd_bus_slot_ref(slot);
+        bus->current_handler = c->callback;
+        bus->current_userdata = slot->userdata;
+        r = c->callback(m, slot->userdata, &error_buffer);
+        bus->current_userdata = NULL;
+        bus->current_handler = NULL;
+        bus->current_slot = NULL;
+        bus->current_message = NULL;
 
-                bus->current_message = m;
-                bus->current_slot = sd_bus_slot_ref(slot);
-                bus->current_handler = c->callback;
-                bus->current_userdata = slot->userdata;
-                r = c->callback(m, slot->userdata, &error_buffer);
-                bus->current_userdata = NULL;
-                bus->current_handler = NULL;
-                bus->current_slot = NULL;
-                bus->current_message = NULL;
+        if (slot->floating) {
+                bus_slot_disconnect(slot);
+                sd_bus_slot_unref(slot);
+        }
 
-                if (slot->floating) {
-                        bus_slot_disconnect(slot);
-                        sd_bus_slot_unref(slot);
-                }
+        sd_bus_slot_unref(slot);
 
-                sd_bus_slot_unref(slot);
+        return bus_maybe_reply_error(m, r, &error_buffer);
+}
 
-                return bus_maybe_reply_error(m, r, &error_buffer);
+static int process_closing(sd_bus *bus, sd_bus_message **ret) {
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL;
+        struct reply_callback *c;
+        int r;
+
+        assert(bus);
+        assert(bus->state == BUS_CLOSING);
+
+        /* First, fail all outstanding method calls */
+        c = ordered_hashmap_first(bus->reply_callbacks);
+        if (c)
+                return process_closing_reply_callback(bus, c);
+
+        /* Then, fake-drop all remaining bus tracking references */
+        if (bus->tracks) {
+                bus_track_close(bus->tracks);
+                return 1;
         }
 
         /* Then, synthesize a Disconnected message */
@@ -2727,6 +2767,10 @@ static int process_closing(sd_bus *bus, sd_bus_message **ret) {
         if (r != 0)
                 goto finish;
 
+        /* Nothing else to do, exit now, if the condition holds */
+        bus->exit_triggered = true;
+        (void) bus_exit_now(bus);
+
         if (ret) {
                 *ret = m;
                 m = NULL;
@@ -3789,3 +3833,21 @@ _public_ void sd_bus_default_flush_close(void) {
         flush_close(default_user_bus);
         flush_close(default_system_bus);
 }
+
+_public_ int sd_bus_set_exit_on_disconnect(sd_bus *bus, int b) {
+        assert_return(bus, -EINVAL);
+
+        /* Turns on exit-on-disconnect, and triggers it immediately if the bus connection was already
+         * disconnected. Note that this is triggered exclusively on disconnections triggered by the server side, never
+         * from the client side. */
+        bus->exit_on_disconnect = b;
+
+        /* If the exit condition was triggered already, exit immediately. */
+        return bus_exit_now(bus);
+}
+
+_public_ int sd_bus_get_exit_on_disconnect(sd_bus *bus) {
+        assert_return(bus, -EINVAL);
+
+        return bus->exit_on_disconnect;
+}
diff --git a/src/libsystemd/sd-bus/test-bus-track.c b/src/libsystemd/sd-bus/test-bus-track.c
new file mode 100644
index 0000000000..4beb61f05a
--- /dev/null
+++ b/src/libsystemd/sd-bus/test-bus-track.c
@@ -0,0 +1,113 @@
+/***
+  This file is part of systemd.
+
+  Copyright 2016 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as published by
+  the Free Software Foundation; either version 2.1 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sd-bus.h>
+
+#include "macro.h"
+
+static bool track_cb_called_x = false;
+static bool track_cb_called_y = false;
+
+static int track_cb_x(sd_bus_track *t, void *userdata) {
+
+        log_error("TRACK CB X");
+
+        assert_se(!track_cb_called_x);
+        track_cb_called_x = true;
+
+        /* This means b's name disappeared. Let's now disconnect, to make sure the track handling on disconnect works
+         * as it should. */
+
+        assert_se(shutdown(sd_bus_get_fd(sd_bus_track_get_bus(t)), SHUT_RDWR) >= 0);
+        return 1;
+}
+
+static int track_cb_y(sd_bus_track *t, void *userdata) {
+        int r;
+
+        log_error("TRACK CB Y");
+
+        assert_se(!track_cb_called_y);
+        track_cb_called_y = true;
+
+        /* We got disconnected, let's close everything */
+
+        r = sd_event_exit(sd_bus_get_event(sd_bus_track_get_bus(t)), EXIT_SUCCESS);
+        assert_se(r >= 0);
+
+        return 0;
+}
+
+int main(int argc, char *argv[]) {
+        _cleanup_(sd_event_unrefp) sd_event *event = NULL;
+        _cleanup_(sd_bus_track_unrefp) sd_bus_track *x = NULL, *y = NULL;
+        _cleanup_(sd_bus_unrefp) sd_bus *a = NULL, *b = NULL;
+        const char *unique;
+        int r;
+
+        r = sd_event_default(&event);
+        assert_se(r >= 0);
+
+        r = sd_bus_open_system(&a);
+        if (IN_SET(r, -ECONNREFUSED, -ENOENT)) {
+                log_info("Failed to connect to bus, skipping tests.");
+                return EXIT_TEST_SKIP;
+        }
+        assert_se(r >= 0);
+
+        r = sd_bus_attach_event(a, event, SD_EVENT_PRIORITY_NORMAL);
+        assert_se(r >= 0);
+
+        r = sd_bus_open_system(&b);
+        assert_se(r >= 0);
+
+        r = sd_bus_attach_event(b, event, SD_EVENT_PRIORITY_NORMAL);
+        assert_se(r >= 0);
+
+        /* Watch b's name from a */
+        r = sd_bus_track_new(a, &x, track_cb_x, NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_get_unique_name(b, &unique);
+        assert_se(r >= 0);
+
+        r = sd_bus_track_add_name(x, unique);
+        assert_se(r >= 0);
+
+        /* Watch's a's own name from a */
+        r = sd_bus_track_new(a, &y, track_cb_y, NULL);
+        assert_se(r >= 0);
+
+        r = sd_bus_get_unique_name(a, &unique);
+        assert_se(r >= 0);
+
+        r = sd_bus_track_add_name(y, unique);
+        assert_se(r >= 0);
+
+        /* Now make b's name disappear */
+        sd_bus_close(b);
+
+        r = sd_event_loop(event);
+        assert_se(r >= 0);
+
+        assert_se(track_cb_called_x);
+        assert_se(track_cb_called_y);
+
+        return 0;
+}
diff --git a/src/run/run.c b/src/run/run.c
index e8586ef61a..2dd229868c 100644
--- a/src/run/run.c
+++ b/src/run/run.c
@@ -33,6 +33,7 @@
 #include "formats-util.h"
 #include "parse-util.h"
 #include "path-util.h"
+#include "process-util.h"
 #include "ptyfwd.h"
 #include "signal-util.h"
 #include "spawn-polkit-agent.h"
@@ -45,6 +46,7 @@ static bool arg_ask_password = true;
 static bool arg_scope = false;
 static bool arg_remain_after_exit = false;
 static bool arg_no_block = false;
+static bool arg_wait = false;
 static const char *arg_unit = NULL;
 static const char *arg_description = NULL;
 static const char *arg_slice = NULL;
@@ -97,6 +99,7 @@ static void help(void) {
                "     --slice=SLICE                Run in the specified slice\n"
                "     --no-block                   Do not wait until operation finished\n"
                "  -r --remain-after-exit          Leave service around until explicitly stopped\n"
+               "     --wait                       Wait until service stopped again\n"
                "     --send-sighup                Send SIGHUP when terminating\n"
                "     --service-type=TYPE          Service type\n"
                "     --uid=USER                   Run as system user\n"
@@ -144,6 +147,7 @@ static int parse_argv(int argc, char *argv[]) {
                 ARG_TIMER_PROPERTY,
                 ARG_NO_BLOCK,
                 ARG_NO_ASK_PASSWORD,
+                ARG_WAIT,
         };
 
         static const struct option options[] = {
@@ -160,6 +164,7 @@ static int parse_argv(int argc, char *argv[]) {
                 { "host",              required_argument, NULL, 'H'                  },
                 { "machine",           required_argument, NULL, 'M'                  },
                 { "service-type",      required_argument, NULL, ARG_SERVICE_TYPE     },
+                { "wait",              no_argument,       NULL, ARG_WAIT             },
                 { "uid",               required_argument, NULL, ARG_EXEC_USER        },
                 { "gid",               required_argument, NULL, ARG_EXEC_GROUP       },
                 { "nice",              required_argument, NULL, ARG_NICE             },
@@ -357,6 +362,10 @@ static int parse_argv(int argc, char *argv[]) {
                         arg_no_block = true;
                         break;
 
+                case ARG_WAIT:
+                        arg_wait = true;
+                        break;
+
                 case '?':
                         return -EINVAL;
 
@@ -404,6 +413,23 @@ static int parse_argv(int argc, char *argv[]) {
                 return -EINVAL;
         }
 
+        if (arg_wait) {
+                if (arg_no_block) {
+                        log_error("--wait may not be combined with --no-block.");
+                        return -EINVAL;
+                }
+
+                if (with_timer()) {
+                        log_error("--wait may not be combined with timer operations.");
+                        return -EINVAL;
+                }
+
+                if (arg_scope) {
+                        log_error("--wait may not be combined with --scope.");
+                        return -EINVAL;
+                }
+        }
+
         return 1;
 }
 
@@ -466,6 +492,12 @@ static int transient_service_set_properties(sd_bus_message *m, char **argv, cons
         if (r < 0)
                 return r;
 
+        if (arg_wait) {
+                r = sd_bus_message_append(m, "(sv)", "AddRef", "b", 1);
+                if (r < 0)
+                        return r;
+        }
+
         if (arg_remain_after_exit) {
                 r = sd_bus_message_append(m, "(sv)", "RemainAfterExit", "b", arg_remain_after_exit);
                 if (r < 0)
@@ -723,9 +755,97 @@ static int make_unit_name(sd_bus *bus, UnitType t, char **ret) {
         return 0;
 }
 
+typedef struct RunContext {
+        sd_bus *bus;
+        sd_event *event;
+        PTYForward *forward;
+        sd_bus_slot *match;
+
+        /* The exit data of the unit */
+        char *active_state;
+        uint64_t inactive_exit_usec;
+        uint64_t inactive_enter_usec;
+        char *result;
+        uint64_t cpu_usage_nsec;
+        uint32_t exit_code;
+        uint32_t exit_status;
+} RunContext;
+
+static void run_context_free(RunContext *c) {
+        assert(c);
+
+        c->forward = pty_forward_free(c->forward);
+        c->match = sd_bus_slot_unref(c->match);
+        c->bus = sd_bus_unref(c->bus);
+        c->event = sd_event_unref(c->event);
+
+        free(c->active_state);
+        free(c->result);
+}
+
+static void run_context_check_done(RunContext *c) {
+        bool done = true;
+
+        assert(c);
+
+        if (c->match)
+                done = done && (c->active_state && STR_IN_SET(c->active_state, "inactive", "failed"));
+
+        if (c->forward)
+                done = done && pty_forward_is_done(c->forward);
+
+        if (done)
+                sd_event_exit(c->event, EXIT_SUCCESS);
+}
+
+static int on_properties_changed(sd_bus_message *m, void *userdata, sd_bus_error *error) {
+
+        static const struct bus_properties_map map[] = {
+                { "ActiveState",                      "s", NULL, offsetof(RunContext, active_state)        },
+                { "InactiveExitTimestampMonotonic",   "t", NULL, offsetof(RunContext, inactive_exit_usec)  },
+                { "InactiveEnterTimestampMonotonic",  "t", NULL, offsetof(RunContext, inactive_enter_usec) },
+                { "Result",                           "s", NULL, offsetof(RunContext, result)              },
+                { "ExecMainCode",                     "i", NULL, offsetof(RunContext, exit_code)           },
+                { "ExecMainStatus",                   "i", NULL, offsetof(RunContext, exit_status)         },
+                { "CPUUsageNSec",                     "t", NULL, offsetof(RunContext, cpu_usage_nsec)      },
+                {}
+        };
+
+        RunContext *c = userdata;
+        int r;
+
+        r = bus_map_all_properties(c->bus,
+                                   "org.freedesktop.systemd1",
+                                   sd_bus_message_get_path(m),
+                                   map,
+                                   c);
+        if (r < 0) {
+                sd_event_exit(c->event, EXIT_FAILURE);
+                return log_error_errno(r, "Failed to query unit state: %m");
+        }
+
+        run_context_check_done(c);
+        return 0;
+}
+
+static int pty_forward_handler(PTYForward *f, int rcode, void *userdata) {
+        RunContext *c = userdata;
+
+        assert(f);
+
+        if (rcode < 0) {
+                sd_event_exit(c->event, EXIT_FAILURE);
+                return log_error_errno(rcode, "Error on PTY forwarding logic: %m");
+        }
+
+        run_context_check_done(c);
+        return 0;
+}
+
 static int start_transient_service(
                 sd_bus *bus,
-                char **argv) {
+                char **argv,
+                int *retval) {
 
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
@@ -736,6 +856,7 @@ static int start_transient_service(
 
         assert(bus);
         assert(argv);
+        assert(retval);
 
         if (arg_pty) {
 
@@ -859,40 +980,95 @@ static int start_transient_service(
                         return r;
         }
 
-        if (master >= 0) {
-                _cleanup_(pty_forward_freep) PTYForward *forward = NULL;
-                _cleanup_(sd_event_unrefp) sd_event *event = NULL;
-                char last_char = 0;
+        if (!arg_quiet)
+                log_info("Running as unit: %s", service);
+
+        if (arg_wait || master >= 0) {
+                _cleanup_(run_context_free) RunContext c = {};
 
-                r = sd_event_default(&event);
+                c.bus = sd_bus_ref(bus);
+
+                r = sd_event_default(&c.event);
                 if (r < 0)
                         return log_error_errno(r, "Failed to get event loop: %m");
 
-                assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGWINCH, SIGTERM, SIGINT, -1) >= 0);
+                if (master >= 0) {
+                        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGWINCH, SIGTERM, SIGINT, -1) >= 0);
+                        (void) sd_event_add_signal(c.event, NULL, SIGINT, NULL, NULL);
+                        (void) sd_event_add_signal(c.event, NULL, SIGTERM, NULL, NULL);
+
+                        if (!arg_quiet)
+                                log_info("Press ^] three times within 1s to disconnect TTY.");
 
-                (void) sd_event_add_signal(event, NULL, SIGINT, NULL, NULL);
-                (void) sd_event_add_signal(event, NULL, SIGTERM, NULL, NULL);
+                        r = pty_forward_new(c.event, master, PTY_FORWARD_IGNORE_INITIAL_VHANGUP, &c.forward);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to create PTY forwarder: %m");
+
+                        pty_forward_set_handler(c.forward, pty_forward_handler, &c);
+                }
 
-                if (!arg_quiet)
-                        log_info("Running as unit: %s\nPress ^] three times within 1s to disconnect TTY.", service);
+                if (arg_wait) {
+                        _cleanup_free_ char *path = NULL;
+                        const char *mt;
 
-                r = pty_forward_new(event, master, PTY_FORWARD_IGNORE_INITIAL_VHANGUP, &forward);
-                if (r < 0)
-                        return log_error_errno(r, "Failed to create PTY forwarder: %m");
+                        path = unit_dbus_path_from_name(service);
+                        if (!path)
+                                return log_oom();
+
+                        mt = strjoina("type='signal',"
+                                      "sender='org.freedesktop.systemd1',"
+                                      "path='", path, "',"
+                                      "interface='org.freedesktop.DBus.Properties',"
+                                      "member='PropertiesChanged'");
+                        r = sd_bus_add_match(bus, &c.match, mt, on_properties_changed, &c);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to add properties changed signal.");
 
-                r = sd_event_loop(event);
+                        r = sd_bus_attach_event(bus, c.event, 0);
+                        if (r < 0)
+                                return log_error_errno(r, "Failed to attach bus to event loop.");
+                }
+
+                r = sd_event_loop(c.event);
                 if (r < 0)
                         return log_error_errno(r, "Failed to run event loop: %m");
 
-                pty_forward_get_last_char(forward, &last_char);
+                if (c.forward) {
+                        char last_char = 0;
 
-                forward = pty_forward_free(forward);
+                        r = pty_forward_get_last_char(c.forward, &last_char);
+                        if (r >= 0 && !arg_quiet && last_char != '\n')
+                                fputc('\n', stdout);
+                }
 
-                if (!arg_quiet && last_char != '\n')
-                        fputc('\n', stdout);
+                if (!arg_quiet) {
+                        if (!isempty(c.result))
+                                log_info("Finished with result: %s", strna(c.result));
 
-        } else if (!arg_quiet)
-                log_info("Running as unit: %s", service);
+                        if (c.exit_code == CLD_EXITED)
+                                log_info("Main processes terminated with: code=%s/status=%i", sigchld_code_to_string(c.exit_code), c.exit_status);
+                        else if (c.exit_code > 0)
+                                log_info("Main processes terminated with: code=%s/status=%s", sigchld_code_to_string(c.exit_code), signal_to_string(c.exit_status));
+
+                        if (c.inactive_enter_usec > 0 && c.inactive_enter_usec != USEC_INFINITY &&
+                            c.inactive_exit_usec > 0 && c.inactive_exit_usec != USEC_INFINITY &&
+                            c.inactive_enter_usec > c.inactive_exit_usec) {
+                                char ts[FORMAT_TIMESPAN_MAX];
+                                log_info("Service runtime: %s", format_timespan(ts, sizeof(ts), c.inactive_enter_usec - c.inactive_exit_usec, USEC_PER_MSEC));
+                        }
+
+                        if (c.cpu_usage_nsec > 0 && c.cpu_usage_nsec != NSEC_INFINITY) {
+                                char ts[FORMAT_TIMESPAN_MAX];
+                                log_info("CPU time consumed: %s", format_timespan(ts, sizeof(ts), (c.cpu_usage_nsec + NSEC_PER_USEC - 1) / NSEC_PER_USEC, USEC_PER_MSEC));
+                        }
+                }
+
+                /* Try to propagate the service's return value */
+                if (c.result && STR_IN_SET(c.result, "success", "exit-code") && c.exit_code == CLD_EXITED)
+                        *retval = c.exit_status;
+                else
+                        *retval = EXIT_FAILURE;
+        }
 
         return 0;
 }
@@ -1197,7 +1373,7 @@ static int start_transient_timer(
 int main(int argc, char* argv[]) {
         _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
         _cleanup_free_ char *description = NULL, *command = NULL;
-        int r;
+        int r, retval = EXIT_SUCCESS;
 
         log_parse_environment();
         log_open();
@@ -1234,7 +1410,12 @@ int main(int argc, char* argv[]) {
                 arg_description = description;
         }
 
-        r = bus_connect_transport_systemd(arg_transport, arg_host, arg_user, &bus);
+        /* If --wait is used connect via the bus, unconditionally, as ref/unref is not supported via the limited direct
+         * connection */
+        if (arg_wait)
+                r = bus_connect_transport(arg_transport, arg_host, arg_user, &bus);
+        else
+                r = bus_connect_transport_systemd(arg_transport, arg_host, arg_user, &bus);
         if (r < 0) {
                 log_error_errno(r, "Failed to create bus connection: %m");
                 goto finish;
@@ -1245,12 +1426,12 @@ int main(int argc, char* argv[]) {
         else if (with_timer())
                 r = start_transient_timer(bus, argv + optind);
         else
-                r = start_transient_service(bus, argv + optind);
+                r = start_transient_service(bus, argv + optind, &retval);
 
 finish:
         strv_free(arg_environment);
         strv_free(arg_property);
         strv_free(arg_timer_property);
 
-        return r < 0 ? EXIT_FAILURE : EXIT_SUCCESS;
+        return r < 0 ? EXIT_FAILURE : retval;
 }
diff --git a/src/shared/bus-util.c b/src/shared/bus-util.c
index 52410999cf..e2a216a5cc 100644
--- a/src/shared/bus-util.c
+++ b/src/shared/bus-util.c
@@ -1016,19 +1016,19 @@ static int map_basic(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_
                 return r;
 
         switch (type) {
+
         case SD_BUS_TYPE_STRING: {
-                const char *s;
                 char **p = userdata;
+                const char *s;
 
                 r = sd_bus_message_read_basic(m, type, &s);
                 if (r < 0)
-                        break;
+                        return r;
 
                 if (isempty(s))
-                        break;
+                        s = NULL;
 
-                r = free_and_strdup(p, s);
-                break;
+                return free_and_strdup(p, s);
         }
 
         case SD_BUS_TYPE_ARRAY: {
@@ -1037,13 +1037,12 @@ static int map_basic(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_
 
                 r = bus_message_read_strv_extend(m, &l);
                 if (r < 0)
-                        break;
+                        return r;
 
                 strv_free(*p);
                 *p = l;
                 l = NULL;
-
-                break;
+                return 0;
         }
 
         case SD_BUS_TYPE_BOOLEAN: {
@@ -1052,57 +1051,48 @@ static int map_basic(sd_bus *bus, const char *member, sd_bus_message *m, sd_bus_
 
                 r = sd_bus_message_read_basic(m, type, &b);
                 if (r < 0)
-                        break;
+                        return r;
 
                 *p = b;
-
-                break;
+                return 0;
         }
 
+        case SD_BUS_TYPE_INT32:
         case SD_BUS_TYPE_UINT32: {
-                uint32_t u;
-                uint32_t *p = userdata;
+                uint32_t u, *p = userdata;
 
                 r = sd_bus_message_read_basic(m, type, &u);
                 if (r < 0)
-                        break;
+                        return r;
 
                 *p = u;
-
-                break;
+                return 0;
         }
 
+        case SD_BUS_TYPE_INT64:
         case SD_BUS_TYPE_UINT64: {
-                uint64_t t;
-                uint64_t *p = userdata;
+                uint64_t t, *p = userdata;
 
                 r = sd_bus_message_read_basic(m, type, &t);
                 if (r < 0)
-                        break;
+                        return r;
 
                 *p = t;
-
-                break;
+                return 0;
         }
 
         case SD_BUS_TYPE_DOUBLE: {
-                double d;
-                double *p = userdata;
+                double d, *p = userdata;
 
                 r = sd_bus_message_read_basic(m, type, &d);
                 if (r < 0)
-                        break;
+                        return r;
 
                 *p = d;
+                return 0;
+        }}
 
-                break;
-        }
-
-        default:
-                break;
-        }
-
-        return r;
+        return -EOPNOTSUPP;
 }
 
 int bus_message_map_all_properties(
@@ -1240,12 +1230,13 @@ int bus_map_all_properties(
         return bus_message_map_all_properties(m, map, userdata);
 }
 
-int bus_connect_transport(BusTransport transport, const char *host, bool user, sd_bus **bus) {
+int bus_connect_transport(BusTransport transport, const char *host, bool user, sd_bus **ret) {
+        _cleanup_(sd_bus_unrefp) sd_bus *bus = NULL;
         int r;
 
         assert(transport >= 0);
         assert(transport < _BUS_TRANSPORT_MAX);
-        assert(bus);
+        assert(ret);
 
         assert_return((transport == BUS_TRANSPORT_LOCAL) == !host, -EINVAL);
         assert_return(transport == BUS_TRANSPORT_LOCAL || !user, -EOPNOTSUPP);
@@ -1254,25 +1245,34 @@ int bus_connect_transport(BusTransport transport, const char *host, bool user, s
 
         case BUS_TRANSPORT_LOCAL:
                 if (user)
-                        r = sd_bus_default_user(bus);
+                        r = sd_bus_default_user(&bus);
                 else
-                        r = sd_bus_default_system(bus);
+                        r = sd_bus_default_system(&bus);
 
                 break;
 
         case BUS_TRANSPORT_REMOTE:
-                r = sd_bus_open_system_remote(bus, host);
+                r = sd_bus_open_system_remote(&bus, host);
                 break;
 
         case BUS_TRANSPORT_MACHINE:
-                r = sd_bus_open_system_machine(bus, host);
+                r = sd_bus_open_system_machine(&bus, host);
                 break;
 
         default:
                 assert_not_reached("Hmm, unknown transport type.");
         }
+        if (r < 0)
+                return r;
 
-        return r;
+        r = sd_bus_set_exit_on_disconnect(bus, true);
+        if (r < 0)
+                return r;
+
+        *ret = bus;
+        bus = NULL;
+
+        return 0;
 }
 
 int bus_connect_transport_systemd(BusTransport transport, const char *host, bool user, sd_bus **bus) {
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index 02c03b98d8..24055e772b 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -68,6 +68,8 @@ struct PTYForward {
 
         bool read_from_master:1;
 
+        bool done:1;
+
         bool last_char_set:1;
         char last_char;
 
@@ -76,10 +78,54 @@ struct PTYForward {
 
         usec_t escape_timestamp;
         unsigned escape_counter;
+
+        PTYForwardHandler handler;
+        void *userdata;
 };
 
 #define ESCAPE_USEC (1*USEC_PER_SEC)
 
+static void pty_forward_disconnect(PTYForward *f) {
+
+        if (f) {
+                f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
+                f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
+
+                f->master_event_source = sd_event_source_unref(f->master_event_source);
+                f->sigwinch_event_source = sd_event_source_unref(f->sigwinch_event_source);
+                f->event = sd_event_unref(f->event);
+
+                if (f->saved_stdout)
+                        tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr);
+                if (f->saved_stdin)
+                        tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr);
+
+                f->saved_stdout = f->saved_stdin = false;
+        }
+
+        /* STDIN/STDOUT should not be nonblocking normally, so let's unconditionally reset it */
+        fd_nonblock(STDIN_FILENO, false);
+        fd_nonblock(STDOUT_FILENO, false);
+}
+
+static int pty_forward_done(PTYForward *f, int rcode) {
+        _cleanup_(sd_event_unrefp) sd_event *e = NULL;
+        assert(f);
+
+        if (f->done)
+                return 0;
+
+        e = sd_event_ref(f->event);
+
+        f->done = true;
+        pty_forward_disconnect(f);
+
+        if (f->handler)
+                return f->handler(f, rcode, f->userdata);
+        else
+                return sd_event_exit(e, rcode < 0 ? EXIT_FAILURE : rcode);
+}
+
 static bool look_for_escape(PTYForward *f, const char *buffer, size_t n) {
         const char *p;
 
@@ -147,7 +193,7 @@ static int shovel(PTYForward *f) {
                                         f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
                                 } else {
                                         log_error_errno(errno, "read(): %m");
-                                        return sd_event_exit(f->event, EXIT_FAILURE);
+                                        return pty_forward_done(f, -errno);
                                 }
                         } else if (k == 0) {
                                 /* EOF on stdin */
@@ -156,12 +202,10 @@ static int shovel(PTYForward *f) {
 
                                 f->stdin_event_source = sd_event_source_unref(f->stdin_event_source);
                         } else  {
-                                /* Check if ^] has been
-                                 * pressed three times within
-                                 * one second. If we get this
-                                 * we quite immediately. */
+                                /* Check if ^] has been pressed three times within one second. If we get this we quite
+                                 * immediately. */
                                 if (look_for_escape(f, f->in_buffer + f->in_buffer_full, k))
-                                        return sd_event_exit(f->event, EXIT_FAILURE);
+                                        return pty_forward_done(f, -ECANCELED);
 
                                 f->in_buffer_full += (size_t) k;
                         }
@@ -181,7 +225,7 @@ static int shovel(PTYForward *f) {
                                         f->master_event_source = sd_event_source_unref(f->master_event_source);
                                 } else {
                                         log_error_errno(errno, "write(): %m");
-                                        return sd_event_exit(f->event, EXIT_FAILURE);
+                                        return pty_forward_done(f, -errno);
                                 }
                         } else {
                                 assert(f->in_buffer_full >= (size_t) k);
@@ -211,7 +255,7 @@ static int shovel(PTYForward *f) {
                                         f->master_event_source = sd_event_source_unref(f->master_event_source);
                                 } else {
                                         log_error_errno(errno, "read(): %m");
-                                        return sd_event_exit(f->event, EXIT_FAILURE);
+                                        return pty_forward_done(f, -errno);
                                 }
                         }  else {
                                 f->read_from_master = true;
@@ -232,7 +276,7 @@ static int shovel(PTYForward *f) {
                                         f->stdout_event_source = sd_event_source_unref(f->stdout_event_source);
                                 } else {
                                         log_error_errno(errno, "write(): %m");
-                                        return sd_event_exit(f->event, EXIT_FAILURE);
+                                        return pty_forward_done(f, -errno);
                                 }
 
                         } else {
@@ -255,7 +299,7 @@ static int shovel(PTYForward *f) {
 
                 if ((f->out_buffer_full <= 0 || f->stdout_hangup) &&
                     (f->in_buffer_full <= 0 || f->master_hangup))
-                        return sd_event_exit(f->event, EXIT_SUCCESS);
+                        return pty_forward_done(f, 0);
         }
 
         return 0;
@@ -418,27 +462,8 @@ int pty_forward_new(
 }
 
 PTYForward *pty_forward_free(PTYForward *f) {
-
-        if (f) {
-                sd_event_source_unref(f->stdin_event_source);
-                sd_event_source_unref(f->stdout_event_source);
-                sd_event_source_unref(f->master_event_source);
-                sd_event_source_unref(f->sigwinch_event_source);
-                sd_event_unref(f->event);
-
-                if (f->saved_stdout)
-                        tcsetattr(STDOUT_FILENO, TCSANOW, &f->saved_stdout_attr);
-                if (f->saved_stdin)
-                        tcsetattr(STDIN_FILENO, TCSANOW, &f->saved_stdin_attr);
-
-                free(f);
-        }
-
-        /* STDIN/STDOUT should not be nonblocking normally, so let's
-         * unconditionally reset it */
-        fd_nonblock(STDIN_FILENO, false);
-        fd_nonblock(STDOUT_FILENO, false);
-
+        pty_forward_disconnect(f);
+        free(f);
         return NULL;
 }
 
@@ -477,8 +502,21 @@ int pty_forward_set_ignore_vhangup(PTYForward *f, bool b) {
         return 0;
 }
 
-int pty_forward_get_ignore_vhangup(PTYForward *f) {
+bool pty_forward_get_ignore_vhangup(PTYForward *f) {
         assert(f);
 
         return !!(f->flags & PTY_FORWARD_IGNORE_VHANGUP);
 }
+
+bool pty_forward_is_done(PTYForward *f) {
+        assert(f);
+
+        return f->done;
+}
+
+void pty_forward_set_handler(PTYForward *f, PTYForwardHandler cb, void *userdata) {
+        assert(f);
+
+        f->handler = cb;
+        f->userdata = userdata;
+}
diff --git a/src/shared/ptyfwd.h b/src/shared/ptyfwd.h
index a046eb4e5e..bd5d5fec0d 100644
--- a/src/shared/ptyfwd.h
+++ b/src/shared/ptyfwd.h
@@ -37,12 +37,18 @@ typedef enum PTYForwardFlags {
         PTY_FORWARD_IGNORE_INITIAL_VHANGUP = 4,
 } PTYForwardFlags;
 
+typedef int (*PTYForwardHandler)(PTYForward *f, int rcode, void*userdata);
+
 int pty_forward_new(sd_event *event, int master, PTYForwardFlags flags, PTYForward **f);
 PTYForward *pty_forward_free(PTYForward *f);
 
 int pty_forward_get_last_char(PTYForward *f, char *ch);
 
 int pty_forward_set_ignore_vhangup(PTYForward *f, bool ignore_vhangup);
-int pty_forward_get_ignore_vhangup(PTYForward *f);
+bool pty_forward_get_ignore_vhangup(PTYForward *f);
+
+bool pty_forward_is_done(PTYForward *f);
+
+void pty_forward_set_handler(PTYForward *f, PTYForwardHandler handler, void *userdata);
 
 DEFINE_TRIVIAL_CLEANUP_FUNC(PTYForward*, pty_forward_free);
diff --git a/src/shared/seccomp-util.c b/src/shared/seccomp-util.c
index 4667f508c7..6c489284d1 100644
--- a/src/shared/seccomp-util.c
+++ b/src/shared/seccomp-util.c
@@ -137,6 +137,7 @@ const SystemCallFilterSet syscall_filter_sets[] = {
                 "execve\0"
                 "exit\0"
                 "exit_group\0"
+                "getrlimit\0"      /* make sure processes can query stack size and such */
                 "rt_sigreturn\0"
                 "sigreturn\0"
         }, {
diff --git a/src/systemd/sd-bus.h b/src/systemd/sd-bus.h
index 295989cd69..c47459c9ad 100644
--- a/src/systemd/sd-bus.h
+++ b/src/systemd/sd-bus.h
@@ -147,6 +147,8 @@ int sd_bus_can_send(sd_bus *bus, char type);
 int sd_bus_get_creds_mask(sd_bus *bus, uint64_t *creds_mask);
 int sd_bus_set_allow_interactive_authorization(sd_bus *bus, int b);
 int sd_bus_get_allow_interactive_authorization(sd_bus *bus);
+int sd_bus_set_exit_on_disconnect(sd_bus *bus, int b);
+int sd_bus_get_exit_on_disconnect(sd_bus *bus);
 
 int sd_bus_start(sd_bus *ret);
 
@@ -438,8 +440,14 @@ int sd_bus_track_remove_sender(sd_bus_track *track, sd_bus_message *m);
 int sd_bus_track_add_name(sd_bus_track *track, const char *name);
 int sd_bus_track_remove_name(sd_bus_track *track, const char *name);
 
+int sd_bus_track_set_recursive(sd_bus_track *track, int b);
+int sd_bus_track_get_recursive(sd_bus_track *track);
+
 unsigned sd_bus_track_count(sd_bus_track *track);
-const char* sd_bus_track_contains(sd_bus_track *track, const char *names);
+int sd_bus_track_count_sender(sd_bus_track *track, sd_bus_message *m);
+int sd_bus_track_count_name(sd_bus_track *track, const char *name);
+
+const char* sd_bus_track_contains(sd_bus_track *track, const char *name);
 const char* sd_bus_track_first(sd_bus_track *track);
 const char* sd_bus_track_next(sd_bus_track *track);