systemctl: don't show cgroup field for a unit if cgroup is empty

[elogind.git] / src / systemctl / systemctl.c

diff --git a/src/systemctl/systemctl.c b/src/systemctl/systemctl.c
index 6d01756ffb3b3c9ceaa0d0d62f9338e6c27ea300..876e782e7dc83b886df0ebde27a8b26633f73d5c 100644 (file)
--- a/src/systemctl/systemctl.c
+++ b/src/systemctl/systemctl.c
@@ -2265,7 +2265,8 @@ static void print_status_info(UnitStatusInfo *i) {
         if (i->status_text)
                 printf("\t  Status: \"%s\"\n", i->status_text);
 
-        if (i->default_control_group) {
+        if (i->default_control_group &&
+            (i->main_pid > 0 || i->control_pid > 0 || cg_is_empty_by_spec(i->default_control_group, false) == 0)) {
                 unsigned c;
 
                 printf("\t  CGroup: %s\n", i->default_control_group);
@@ -3782,7 +3783,16 @@ static int enable_unit(DBusConnection *bus, char **args) {
         }
 
         if (carries_install_info == 0)
-                log_warning("The unit files have no [Install] section. They are not meant to be enabled using systemctl.");
+                log_warning(
+"The unit files have no [Install] section. They are not meant to be enabled\n"
+"using systemctl.\n"
+"Possible reasons for having this kind of units are:\n"
+"1) A unit may be statically enabled by being symlinked from another unit's\n"
+"   .wants/ or .requires/ directory.\n"
+"2) A unit's purpose may be to act as a helper for some other unit which has\n"
+"   a requirement dependency on it.\n"
+"3) A unit may be started when needed via activation (socket, path, timer,\n"
+"   D-Bus, udev, scripted systemctl call, ...).\n");
 
 finish:
         if (m)