From 9d12709626bccc0cae677a7035f62efe6aabb4ab Mon Sep 17 00:00:00 2001
From: Lennart Poettering <lennart@poettering.net>
Date: Thu, 11 Jul 2013 19:14:38 +0200
Subject: [PATCH 1/1] loginctl: suppress cgroup tree output if cgroup is empty

same for machinectl
---
 src/login/loginctl.c     | 17 ++++++++++++-----
 src/machine/machinectl.c | 13 ++++++++++---
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/src/login/loginctl.c b/src/login/loginctl.c
index 93f4beed3..736db6a11 100644
--- a/src/login/loginctl.c
+++ b/src/login/loginctl.c
@@ -35,8 +35,9 @@
 #include "build.h"
 #include "strv.h"
 #include "unit-name.h"
-#include "cgroup-show.h"
 #include "sysfs-show.h"
+#include "cgroup-show.h"
+#include "cgroup-util.h"
 #include "spawn-polkit-agent.h"
 
 static char **arg_property = NULL;
@@ -262,7 +263,7 @@ static int list_seats(DBusConnection *bus, char **args, unsigned n) {
         return 0;
 }
 
-static int show_unit_cgroup(DBusConnection *bus, const char *interface, const char *unit) {
+static int show_unit_cgroup(DBusConnection *bus, const char *interface, const char *unit, pid_t leader) {
         const char *property = "ControlGroup";
         _cleanup_dbus_message_unref_ DBusMessage *reply = NULL;
         _cleanup_free_ char *path = NULL;
@@ -313,6 +314,12 @@ static int show_unit_cgroup(DBusConnection *bus, const char *interface, const ch
 
         dbus_message_iter_get_basic(&sub, &cgroup);
 
+        if (isempty(cgroup))
+                return 0;
+
+        if (cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, cgroup, false) != 0 && leader <= 0)
+                return 0;
+
         output_flags =
                 arg_all * OUTPUT_SHOW_ALL |
                 arg_full * OUTPUT_FULL_WIDTH;
@@ -323,7 +330,7 @@ static int show_unit_cgroup(DBusConnection *bus, const char *interface, const ch
         else
                 c = 0;
 
-        show_cgroup_by_path(cgroup, "\t\t  ", c, false, output_flags);
+        show_cgroup_and_extra(SYSTEMD_CGROUP_CONTROLLER, cgroup, "\t\t  ", c, false, &leader, leader > 0, output_flags);
         return 0;
 }
 
@@ -441,7 +448,7 @@ static void print_session_status_info(DBusConnection *bus, SessionStatusInfo *i)
 
         if (i->scope) {
                 printf("\t    Unit: %s\n", i->scope);
-                show_unit_cgroup(bus, "org.freedesktop.systemd1.Scope", i->scope);
+                show_unit_cgroup(bus, "org.freedesktop.systemd1.Scope", i->scope, i->leader);
         }
 }
 
@@ -483,7 +490,7 @@ static void print_user_status_info(DBusConnection *bus, UserStatusInfo *i) {
 
         if (i->slice) {
                 printf("\t    Unit: %s\n", i->slice);
-                show_unit_cgroup(bus, "org.freedesktop.systemd1.Slice", i->slice);
+                show_unit_cgroup(bus, "org.freedesktop.systemd1.Slice", i->slice, 0);
         }
 }
 
diff --git a/src/machine/machinectl.c b/src/machine/machinectl.c
index cd640e76a..97c219355 100644
--- a/src/machine/machinectl.c
+++ b/src/machine/machinectl.c
@@ -36,6 +36,7 @@
 #include "strv.h"
 #include "unit-name.h"
 #include "cgroup-show.h"
+#include "cgroup-util.h"
 #include "spawn-polkit-agent.h"
 
 static char **arg_property = NULL;
@@ -125,7 +126,7 @@ static int list_machines(DBusConnection *bus, char **args, unsigned n) {
         return 0;
 }
 
-static int show_scope_cgroup(DBusConnection *bus, const char *unit) {
+static int show_scope_cgroup(DBusConnection *bus, const char *unit, pid_t leader) {
         const char *interface = "org.freedesktop.systemd1.Scope";
         const char *property = "ControlGroup";
         _cleanup_dbus_message_unref_ DBusMessage *reply = NULL;
@@ -177,6 +178,12 @@ static int show_scope_cgroup(DBusConnection *bus, const char *unit) {
 
         dbus_message_iter_get_basic(&sub, &cgroup);
 
+        if (isempty(cgroup))
+                return 0;
+
+        if (cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, cgroup, false) != 0 && leader <= 0)
+                return 0;
+
         output_flags =
                 arg_all * OUTPUT_SHOW_ALL |
                 arg_full * OUTPUT_FULL_WIDTH;
@@ -187,7 +194,7 @@ static int show_scope_cgroup(DBusConnection *bus, const char *unit) {
         else
                 c = 0;
 
-        show_cgroup_by_path(cgroup, "\t\t  ", c, false, output_flags);
+        show_cgroup_and_extra(SYSTEMD_CGROUP_CONTROLLER, cgroup, "\t\t  ", c, false, &leader, leader > 0, output_flags);
         return 0;
 }
 
@@ -249,7 +256,7 @@ static void print_machine_status_info(DBusConnection *bus, MachineStatusInfo *i)
 
         if (i->scope) {
                 printf("\t    Unit: %s\n", i->scope);
-                show_scope_cgroup(bus, i->scope);
+                show_scope_cgroup(bus, i->scope, i->leader);
         }
 }
 
-- 
2.30.2