+ if (ret >= 0)
+ ret = r;
+ } else {
+ char *fn;
+
+ while ((r = cg_read_subgroup(d, &fn)) > 0) {
+ _cleanup_free_ char *p = NULL;
+
+ p = strjoin(path, "/", fn, NULL);
+ free(fn);
+
+ if (!p)
+ return -ENOMEM;
+
+ r = unit_watch_pids_in_path(u, p);
+ if (r < 0 && ret >= 0)
+ ret = r;
+ }
+
+ if (r < 0 && ret >= 0)
+ ret = r;
+ }
+
+ return ret;
+}
+
+int unit_watch_all_pids(Unit *u) {
+ assert(u);
+
+ /* Adds all PIDs from our cgroup to the set of PIDs we
+ * watch. This is a fallback logic for cases where we do not
+ * get reliable cgroup empty notifications: we try to use
+ * SIGCHLD as replacement. */
+
+ if (!u->cgroup_path)
+ return -ENOENT;
+
+ if (cg_unified() > 0) /* On unified we can use proper notifications */
+ return 0;
+
+ return unit_watch_pids_in_path(u, u->cgroup_path);
+}
+
+int unit_notify_cgroup_empty(Unit *u) {
+ int r;
+
+ assert(u);
+
+ if (!u->cgroup_path)
+ return 0;
+
+ r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, u->cgroup_path);
+ if (r <= 0)
+ return r;
+
+ unit_add_to_gc_queue(u);
+
+ if (UNIT_VTABLE(u)->notify_cgroup_empty)
+ UNIT_VTABLE(u)->notify_cgroup_empty(u);
+
+ return 0;
+}
+
+static int on_cgroup_inotify_event(sd_event_source *s, int fd, uint32_t revents, void *userdata) {
+ Manager *m = userdata;
+
+ assert(s);
+ assert(fd >= 0);
+ assert(m);
+
+ for (;;) {
+ union inotify_event_buffer buffer;
+ struct inotify_event *e;
+ ssize_t l;
+
+ l = read(fd, &buffer, sizeof(buffer));
+ if (l < 0) {
+ if (errno == EINTR || errno == EAGAIN)
+ return 0;
+
+ return log_error_errno(errno, "Failed to read control group inotify events: %m");
+ }
+
+ FOREACH_INOTIFY_EVENT(e, buffer, l) {
+ Unit *u;
+
+ if (e->wd < 0)
+ /* Queue overflow has no watch descriptor */
+ continue;
+
+ if (e->mask & IN_IGNORED)
+ /* The watch was just removed */
+ continue;
+
+ u = hashmap_get(m->cgroup_inotify_wd_unit, INT_TO_PTR(e->wd));
+ if (!u) /* Not that inotify might deliver
+ * events for a watch even after it
+ * was removed, because it was queued
+ * before the removal. Let's ignore
+ * this here safely. */
+ continue;
+
+ (void) unit_notify_cgroup_empty(u);
+ }
+ }
+}
+#endif // 0
+
+int manager_setup_cgroup(Manager *m) {
+ _cleanup_free_ char *path = NULL;
+ CGroupController c;
+ int r, unified;
+ char *e;
+
+ assert(m);
+
+ /* 1. Determine hierarchy */
+ m->cgroup_root = mfree(m->cgroup_root);
+ 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");
+
+/// elogind does not support systemd scopes and slices
+#if 0
+ /* Chop off the init scope, if we are already located in it */
+ e = endswith(m->cgroup_root, "/" SPECIAL_INIT_SCOPE);
+
+ /* LEGACY: Also chop off the system slice if we are in
+ * it. This is to support live upgrades from older systemd
+ * versions where PID 1 was moved there. Also see
+ * cg_get_root_path(). */
+ if (!e && m->running_as == MANAGER_SYSTEM) {
+ e = endswith(m->cgroup_root, "/" SPECIAL_SYSTEM_SLICE);
+ if (!e)
+ e = endswith(m->cgroup_root, "/system"); /* even more legacy */
+ }
+ if (e)
+ *e = 0;
+#endif // 0
+
+ /* And make sure to store away the root value without trailing
+ * slash, even for the root dir, so that we can easily prepend
+ * it everywhere. */
+ while ((e = endswith(m->cgroup_root, "/")))
+ *e = 0;
+ log_debug_elogind("Cgroup Controller \"%s\" -> root \"%s\"",
+ SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root);
+
+ /* 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");
+
+ unified = cg_unified();
+ if (unified < 0)
+ return log_error_errno(r, "Couldn't determine if we are running in the unified hierarchy: %m");
+ if (unified > 0)
+ log_debug("Unified cgroup hierarchy is located at %s.", path);
+ else
+ log_debug("Using cgroup controller " SYSTEMD_CGROUP_CONTROLLER ". File system hierarchy is at %s.", path);
+
+ if (!m->test_run) {
+ const char *scope_path;
+
+ /* 3. Install agent */
+ if (unified) {
+
+ /* In the unified hierarchy we can can get
+ * cgroup empty notifications via inotify. */
+
+/// elogind does not support the unified hierarchy, yet.
+#if 0
+ m->cgroup_inotify_event_source = sd_event_source_unref(m->cgroup_inotify_event_source);
+ safe_close(m->cgroup_inotify_fd);
+
+ m->cgroup_inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+ if (m->cgroup_inotify_fd < 0)
+ return log_error_errno(errno, "Failed to create control group inotify object: %m");
+
+ r = sd_event_add_io(m->event, &m->cgroup_inotify_event_source, m->cgroup_inotify_fd, EPOLLIN, on_cgroup_inotify_event, m);
+ if (r < 0)
+ return log_error_errno(r, "Failed to watch control group inotify object: %m");
+
+ r = sd_event_source_set_priority(m->cgroup_inotify_event_source, SD_EVENT_PRIORITY_IDLE - 5);
+ if (r < 0)
+ return log_error_errno(r, "Failed to set priority of inotify event source: %m");
+
+ (void) sd_event_source_set_description(m->cgroup_inotify_event_source, "cgroup-inotify");
+
+#else
+ return log_error_errno(EOPNOTSUPP, "Unified cgroup hierarchy not supported: %m");
+#endif // 0
+ } else if (m->running_as == MANAGER_SYSTEM) {
+
+ /* On the legacy hierarchy we only get
+ * notifications via cgroup agents. (Which
+ * isn't really reliable, since it does not
+ * generate events when control groups with
+ * children run empty. */
+
+ r = cg_install_release_agent(SYSTEMD_CGROUP_CONTROLLER, ELOGIND_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 if (r == 0)
+ log_debug("Release agent already installed.");
+ }
+
+/// elogind is not meant to run in systemd init scope
+#if 0
+ /* 4. Make sure we are in the special "init.scope" unit in the root slice. */
+ scope_path = strjoina(m->cgroup_root, "/" SPECIAL_INIT_SCOPE);
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, scope_path, 0);
+#else
+ if (streq(SYSTEMD_CGROUP_CONTROLLER, "name=elogind"))
+ // we are our own cgroup controller
+ scope_path = strjoina("");
+ else if (streq(m->cgroup_root, "/elogind"))
+ // root already is our cgroup
+ scope_path = strjoina(m->cgroup_root);
+ else
+ // we have to create our own group
+ scope_path = strjoina(m->cgroup_root, "/elogind");
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, scope_path, 0);
+#endif // 0
+ if (r < 0)
+ return log_error_errno(r, "Failed to create %s control group: %m", scope_path);
+ log_debug_elogind("Created control group \"%s\"", scope_path);
+
+ /* also, move all other userspace processes remaining
+ * in the root cgroup into that scope. */
+ if (!streq(m->cgroup_root, scope_path)) {
+ r = cg_migrate(SYSTEMD_CGROUP_CONTROLLER, m->cgroup_root, SYSTEMD_CGROUP_CONTROLLER, scope_path, false);
+ if (r < 0)
+ log_warning_errno(r, "Couldn't move remaining userspace processes, ignoring: %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");
+
+ /* 6. Always enable hierarchical support if it exists... */
+ if (!unified)
+ (void) cg_set_attribute("memory", "/", "memory.use_hierarchy", "1");