cgls: make function to query cgroup root public

No functional change.

1 files changed, 55 insertions, 0 deletions

diff --git a/src/shared/cgroup-show.c b/src/shared/cgroup-show.c
index f5bb0603c3..105710436e 100644
--- a/src/shared/cgroup-show.c
+++ b/src/shared/cgroup-show.c
@@ -24,10 +24,15 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include <systemd/sd-bus.h>
+
 #include "alloc-util.h"
+#include "bus-error.h"
+#include "bus-util.h"
 #include "cgroup-show.h"
 #include "cgroup-util.h"
 #include "fd-util.h"
+#include "fileio.h"
 #include "format-util.h"
 #include "locale-util.h"
 #include "macro.h"
@@ -36,6 +41,7 @@
 #include "process-util.h"
 #include "string-util.h"
 #include "terminal-util.h"
+#include "unit-name.h"
 
 static void show_pid_array(
                 pid_t pids[],
@@ -310,3 +316,52 @@ int show_cgroup_and_extra_by_spec(
 
         return show_cgroup_and_extra(controller, path, prefix, n_columns, extra_pids, n_extra_pids, flags);
 }
+
+int show_cgroup_get_root_and_warn(
+                const char *machine,
+                char **ret) {
+
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+        _cleanup_free_ char *unit = NULL, *path = NULL;
+        const char *m;
+        int r;
+
+        if (!machine) {
+                r = cg_get_root_path(ret);
+                if (r == -ENOMEDIUM)
+                        return log_error_errno(r, "Failed to get root control group path.\n"
+                                                  "No cgroup filesystem mounted on /sys/fs/cgroup");
+                else if (r < 0)
+                        return log_error_errno(r, "Failed to get root control group path: %m");
+
+                return 0;
+        }
+
+        m = strjoina("/run/systemd/machines/", machine);
+        r = parse_env_file(m, NEWLINE, "SCOPE", &unit, NULL);
+        if (r < 0)
+                return log_error_errno(r, "Failed to load machine data: %m");
+
+        path = unit_dbus_path_from_name(unit);
+        if (!path)
+                return log_oom();
+
+        r = bus_connect_transport_systemd(BUS_TRANSPORT_LOCAL, NULL, false, &bus);
+        if (r < 0)
+                return log_error_errno(r, "Failed to create bus connection: %m");
+
+        r = sd_bus_get_property_string(
+                        bus,
+                        "org.freedesktop.systemd1",
+                        path,
+                        unit_dbus_interface_from_name(unit),
+                        "ControlGroup",
+                        &error,
+                        ret);
+        if (r < 0)
+                return log_error_errno(r, "Failed to query unit control group path: %s",
+                                       bus_error_message(&error, r));
+
+        return 0;
+}