logind: add infrastructure to keep track of machines, and move to slices

- This changes all logind cgroup objects to use slice objects rather
  than fixed croup locations.

- logind can now collect minimal information about running
  VMs/containers. As fixed cgroup locations can no longer be used we
  need an entity that keeps track of machine cgroups in whatever slice
  they might be located. Since logind already keeps track of users,
  sessions and seats this is a trivial addition.

- nspawn will now register with logind and pass various bits of metadata
  along. A new option "--slice=" has been added to place the container
  in a specific slice.

- loginctl gained commands to list, introspect and terminate machines.

- user.slice and machine.slice will now be pulled in by logind.service,
  since only logind.service requires this slice.

1 files changed, 4 insertions, 4 deletions

diff --git a/src/login/logind-session-dbus.c b/src/login/logind-session-dbus.c
index ec823af547..e306eabb32 100644
--- a/src/login/logind-session-dbus.c
+++ b/src/login/logind-session-dbus.c
@@ -56,6 +56,7 @@
         "  <property name=\"RemoteHost\" type=\"s\" access=\"read\"/>\n" \
         "  <property name=\"RemoteUser\" type=\"s\" access=\"read\"/>\n" \
         "  <property name=\"Service\" type=\"s\" access=\"read\"/>\n"   \
+        "  <property name=\"Slice\" type=\"s\" access=\"read\"/>\n"     \
         "  <property name=\"Leader\" type=\"u\" access=\"read\"/>\n"    \
         "  <property name=\"Audit\" type=\"u\" access=\"read\"/>\n"     \
         "  <property name=\"Type\" type=\"s\" access=\"read\"/>\n"      \
@@ -233,8 +234,8 @@ static int bus_session_append_state(DBusMessageIter *i, const char *property, vo
 }
 
 static int get_session_for_path(Manager *m, const char *path, Session **_s) {
+        _cleanup_free_ char *id = NULL;
         Session *s;
-        char *id;
 
         assert(m);
         assert(path);
@@ -248,8 +249,6 @@ static int get_session_for_path(Manager *m, const char *path, Session **_s) {
                 return -ENOMEM;
 
         s = hashmap_get(m->sessions, id);
-        free(id);
-
         if (!s)
                 return -ENOENT;
 
@@ -270,6 +269,7 @@ static const BusProperty bus_login_session_properties[] = {
         { "RemoteUser",             bus_property_append_string,         "s", offsetof(Session, remote_user),        true },
         { "RemoteHost",             bus_property_append_string,         "s", offsetof(Session, remote_host),        true },
         { "Service",                bus_property_append_string,         "s", offsetof(Session, service),            true },
+        { "Slice",                  bus_property_append_string,         "s", offsetof(Session, slice),              true },
         { "Leader",                 bus_property_append_pid,            "u", offsetof(Session, leader)              },
         { "Audit",                  bus_property_append_uint32,         "u", offsetof(Session, audit_id)            },
         { "Type",                   bus_session_append_type,            "s", offsetof(Session, type)                },
@@ -448,7 +448,7 @@ const DBusObjectPathVTable bus_session_vtable = {
 };
 
 char *session_bus_path(Session *s) {
-        _cleanup_free_ char *t;
+        _cleanup_free_ char *t = NULL;
 
         assert(s);