+static int manager_setup_cgroup(Manager *m) {
+ _cleanup_free_ char *path = NULL;
+ int r;
+
+ assert(m);
+
+ /* 1. Determine hierarchy */
+ free(m->cgroup_root);
+ m->cgroup_root = NULL;
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 0, &m->cgroup_root);
+ if (r < 0)
+ return log_error_errno(r, "Cannot determine cgroup we are running in: %m");
+
+ /* Make sure to store away the root value without trailing
+ * slash, even for the root dir, so that we can easily prepend
+ * it everywhere. */
+ if (streq(m->cgroup_root, "/"))
+ m->cgroup_root[0] = 0;
+
+ /* 2. Show data */
+ r = cg_get_path(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, NULL, &path);
+ if (r < 0)
+ return log_error_errno(r, "Cannot find cgroup mount point: %m");
+
+ log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
+
+ /* 3. Install agent */
+ r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, SYSTEMD_CGROUP_AGENT_PATH);
+ if (r < 0)
+ log_warning_errno(r, "Failed to install release agent, ignoring: %m");
+ else if (r > 0)
+ log_debug("Installed release agent.");
+ else
+ log_debug("Release agent already installed.");
+
+ /* 4. Make sure we are in the root cgroup */
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, 0);
+ if (r < 0)
+ return log_error_errno(r, "Failed to create root cgroup hierarchy: %m");
+
+ /* 5. And pin it, so that it cannot be unmounted */
+ safe_close(m->pin_cgroupfs_fd);
+
+ m->pin_cgroupfs_fd = open(path, O_RDONLY|O_CLOEXEC|O_DIRECTORY|O_NOCTTY|O_NONBLOCK);
+ if (m->pin_cgroupfs_fd < 0)
+ return log_error_errno(errno, "Failed to open pin file: %m");
+
+ return 0;
+}
+