busname: introduce Activating directive

Add a new config 'Activating' directive which denotes whether a busname
is actually registered on the bus. It defaults to 'yes'.

If set to 'no', the .busname unit only uploads policy, which will remain
active as long as the unit is running.

3 files changed, 39 insertions, 21 deletions

diff --git a/src/core/busname.c b/src/core/busname.c
index ccef32e9e7..0cae20d2d1 100644
--- a/src/core/busname.c
+++ b/src/core/busname.c
@@ -29,6 +29,7 @@
 
 static const UnitActiveState state_translation_table[_BUSNAME_STATE_MAX] = {
         [BUSNAME_DEAD] = UNIT_INACTIVE,
+        [BUSNAME_REGISTERED] = UNIT_ACTIVE,
         [BUSNAME_LISTENING] = UNIT_ACTIVE,
         [BUSNAME_RUNNING] = UNIT_ACTIVE,
         [BUSNAME_FAILED] = UNIT_FAILED
@@ -96,20 +97,22 @@ static int busname_add_extras(BusName *n) {
                         return r;
         }
 
-        if (!UNIT_DEREF(n->service)) {
-                Unit *x;
+        if (n->activating) {
+                if (!UNIT_DEREF(n->service)) {
+                        Unit *x;
 
-                r = unit_load_related_unit(u, ".service", &x);
+                        r = unit_load_related_unit(u, ".service", &x);
+                        if (r < 0)
+                                return r;
+
+                        unit_ref_set(&n->service, x);
+                }
+
+                r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, UNIT_DEREF(n->service), true);
                 if (r < 0)
                         return r;
-
-                unit_ref_set(&n->service, x);
         }
 
-        r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, UNIT_DEREF(n->service), true);
-        if (r < 0)
-                return r;
-
         if (u->default_dependencies) {
                 r = busname_add_default_default_dependencies(n);
                 if (r < 0)
@@ -172,10 +175,12 @@ static void busname_dump(Unit *u, FILE *f, const char *prefix) {
                 "%sBus Name State: %s\n"
                 "%sResult: %s\n"
                 "%sName: %s\n"
+                "%sActivating: %s\n"
                 "%sAccept FD: %s\n",
                 prefix, busname_state_to_string(n->state),
                 prefix, busname_result_to_string(n->result),
                 prefix, n->name,
+                prefix, yes_no(n->activating),
                 prefix, yes_no(n->accept_fd));
 }
 
@@ -231,7 +236,7 @@ static int busname_open_fd(BusName *n) {
 
         n->starter_fd = bus_kernel_create_starter(
                         UNIT(n)->manager->running_as == SYSTEMD_SYSTEM ? "system" : "user",
-                        n->name, n->accept_fd, n->policy);
+                        n->name, n->activating, n->accept_fd, n->policy);
 
         if (n->starter_fd < 0) {
                 log_warning_unit(UNIT(n)->id, "Failed to create starter fd: %s", strerror(-n->starter_fd));
@@ -251,7 +256,7 @@ static void busname_set_state(BusName *n, BusNameState state) {
         if (state != BUSNAME_LISTENING)
                 busname_unwatch_fd(n);
 
-        if (!IN_SET(state, BUSNAME_LISTENING, BUSNAME_RUNNING))
+        if (!IN_SET(state, BUSNAME_LISTENING, BUSNAME_REGISTERED, BUSNAME_RUNNING))
                 busname_close_fd(n);
 
         if (state != old_state)
@@ -271,7 +276,7 @@ static int busname_coldplug(Unit *u) {
         if (n->deserialized_state == n->state)
                 return 0;
 
-        if (IN_SET(n->deserialized_state, BUSNAME_LISTENING, BUSNAME_RUNNING)) {
+        if (IN_SET(n->deserialized_state, BUSNAME_LISTENING, BUSNAME_REGISTERED, BUSNAME_RUNNING)) {
                 r = busname_open_fd(n);
                 if (r < 0)
                         return r;
@@ -303,17 +308,23 @@ static void busname_enter_listening(BusName *n) {
 
         r = busname_open_fd(n);
         if (r < 0) {
-                log_warning_unit(UNIT(n)->id, "%s failed to listen on bus names: %s", UNIT(n)->id, strerror(-r));
+                log_warning_unit(UNIT(n)->id, "%s failed to %s: %s", UNIT(n)->id,
+                                 n->activating ? "listen on bus name" : "register policy for name",
+                                 strerror(-r));
                 goto fail;
         }
 
-        r = busname_watch_fd(n);
-        if (r < 0) {
-                log_warning_unit(UNIT(n)->id, "%s failed to watch names: %s", UNIT(n)->id, strerror(-r));
-                goto fail;
-        }
+        if (n->activating) {
+                r = busname_watch_fd(n);
+                if (r < 0) {
+                        log_warning_unit(UNIT(n)->id, "%s failed to watch names: %s", UNIT(n)->id, strerror(-r));
+                        goto fail;
+                }
+
+                busname_set_state(n, BUSNAME_LISTENING);
+        } else
+                busname_set_state(n, BUSNAME_REGISTERED);
 
-        busname_set_state(n, BUSNAME_LISTENING);
         return;
 
 fail:
@@ -329,6 +340,9 @@ static void busname_enter_running(BusName *n) {
 
         assert(n);
 
+        if (!n->activating)
+                return;
+
         /* We don't take conenctions anymore if we are supposed to
          * shut down anyway */
 
@@ -369,7 +383,7 @@ static int busname_start(Unit *u) {
 
         assert(n);
 
-        if (UNIT_ISSET(n->service)) {
+        if (n->activating && UNIT_ISSET(n->service)) {
                 Service *service;
 
                 service = SERVICE(UNIT_DEREF(n->service));
@@ -392,7 +406,7 @@ static int busname_stop(Unit *u) {
         BusName *n = BUSNAME(u);
 
         assert(n);
-        assert(n->state == BUSNAME_LISTENING || n->state == BUSNAME_RUNNING);
+        assert(IN_SET(n->state, BUSNAME_REGISTERED, BUSNAME_LISTENING, BUSNAME_RUNNING));
 
         busname_enter_dead(n, BUSNAME_SUCCESS);
         return 0;
@@ -536,6 +550,7 @@ static void busname_trigger_notify(Unit *u, Unit *other) {
 
 static const char* const busname_state_table[_BUSNAME_STATE_MAX] = {
         [BUSNAME_DEAD] = "dead",
+        [BUSNAME_REGISTERED] = "registered",
         [BUSNAME_LISTENING] = "listening",
         [BUSNAME_RUNNING] = "running",
         [BUSNAME_FAILED] = "failed"
diff --git a/src/core/busname.h b/src/core/busname.h
index 7f591974de..0009c6a65e 100644
--- a/src/core/busname.h
+++ b/src/core/busname.h
@@ -28,6 +28,7 @@ typedef struct BusNamePolicy BusNamePolicy;
 
 typedef enum BusNameState {
         BUSNAME_DEAD,
+        BUSNAME_REGISTERED,
         BUSNAME_LISTENING,
         BUSNAME_RUNNING,
         BUSNAME_FAILED,
@@ -48,6 +49,7 @@ struct BusName {
 
         char *name;
         int starter_fd;
+        bool activating;
 
         UnitRef service;
 
diff --git a/src/core/load-fragment-gperf.gperf.m4 b/src/core/load-fragment-gperf.gperf.m4
index c793a1e25f..1dd9f2b909 100644
--- a/src/core/load-fragment-gperf.gperf.m4
+++ b/src/core/load-fragment-gperf.gperf.m4
@@ -251,6 +251,7 @@ CGROUP_CONTEXT_CONFIG_ITEMS(Socket)m4_dnl
 KILL_CONTEXT_CONFIG_ITEMS(Socket)m4_dnl
 m4_dnl
 BusName.Name,                    config_parse_string,                0,                             offsetof(BusName, name)
+BusName.Activating,              config_parse_bool,                  0,                             offsetof(BusName, activating)
 BusName.Service,                 config_parse_busname_service,       0,                             0
 BusName.AllowUser,               config_parse_bus_policy,            0,                             0
 BusName.AllowGroup,              config_parse_bus_policy,            0,                             0