bus-control: Fix cgroup handling

On systems without properly setup systemd, cg_get_root_path returns
-ENOENT.  This means that busctl doesn't display much information.

busctl monitor also fails whenever it intercepts messages.

This fix fakes creates a fake "/" root cgroup which lets busctl work
on such systems.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/libsystemd/sd-bus/bus-internal.h b/src/libsystemd/sd-bus/bus-internal.h
index f2ccdfd177..601ea5afb1 100644
--- a/src/libsystemd/sd-bus/bus-internal.h
+++ b/src/libsystemd/sd-bus/bus-internal.h
@@ -383,3 +383,5 @@ int bus_set_address_system_remote(sd_bus *b, const char *host);
 int bus_set_address_system_container(sd_bus *b, const char *machine);
 
 int bus_remove_match_by_string(sd_bus *bus, const char *match, sd_bus_message_handler_t callback, void *userdata);
+
+int bus_get_root_path(sd_bus *bus);