+ return strv_uniq(controllers);
+}
+
+int cg_pid_get_path_shifted(pid_t pid, char **root, char **cgroup) {
+ _cleanup_free_ char *cg_root = NULL;
+ char *cg_process, *p;
+ int r;
+
+ r = cg_get_root_path(&cg_root);
+ if (r < 0)
+ return r;
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &cg_process);
+ if (r < 0)
+ return r;
+
+ p = path_startswith(cg_process, cg_root);
+ if (p)
+ p--;
+ else
+ p = cg_process;
+
+ if (cgroup) {
+ char* c;
+
+ c = strdup(p);
+ if (!c) {
+ free(cg_process);
+ return -ENOMEM;
+ }
+
+ *cgroup = c;
+ }
+
+ if (root) {
+ cg_process[p-cg_process] = 0;
+ *root = cg_process;
+ } else
+ free(cg_process);
+
+ return 0;
+}
+
+int cg_path_decode_unit(const char *cgroup, char **unit){
+ char *p, *e, *c, *s, *k;
+
+ assert(cgroup);
+ assert(unit);
+
+ e = strchrnul(cgroup, '/');
+ c = strndupa(cgroup, e - cgroup);
+ c = cg_unescape(c);
+
+ /* Could this be a valid unit name? */
+ if (!unit_name_is_valid(c, true))
+ return -EINVAL;
+
+ if (!unit_name_is_template(c))
+ s = strdup(c);
+ else {
+ if (*e != '/')
+ return -EINVAL;
+
+ e += strspn(e, "/");
+
+ p = strchrnul(e, '/');
+ k = strndupa(e, p - e);
+ k = cg_unescape(k);
+
+ if (!unit_name_is_valid(k, false))
+ return -EINVAL;
+
+ s = strdup(k);
+ }
+
+ if (!s)
+ return -ENOMEM;
+
+ *unit = s;
+ return 0;
+}
+
+int cg_path_get_unit(const char *path, char **unit) {
+ const char *e;
+
+ assert(path);
+ assert(unit);
+
+ e = path_startswith(path, "/system/");
+ if (!e)
+ return -ENOENT;
+
+ return cg_path_decode_unit(e, unit);
+}
+
+int cg_pid_get_unit(pid_t pid, char **unit) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(unit);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_unit(cgroup, unit);
+}
+
+static const char *skip_label(const char *e) {
+ assert(e);
+
+ e = strchr(e, '/');
+ if (!e)
+ return NULL;
+
+ e += strspn(e, "/");
+ return e;
+}
+
+int cg_path_get_user_unit(const char *path, char **unit) {
+ const char *e;
+
+ assert(path);
+ assert(unit);
+
+ /* We always have to parse the path from the beginning as unit
+ * cgroups might have arbitrary child cgroups and we shouldn't get
+ * confused by those */
+
+ e = path_startswith(path, "/user/");
+ if (!e)
+ return -ENOENT;
+
+ /* Skip the user name */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ /* Skip the session ID */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ /* Skip the systemd cgroup */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ return cg_path_decode_unit(e, unit);
+}
+
+int cg_pid_get_user_unit(pid_t pid, char **unit) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(unit);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_user_unit(cgroup, unit);
+}
+
+int cg_path_get_machine_name(const char *path, char **machine) {
+ const char *e, *n;
+ char *s, *r;
+
+ assert(path);
+ assert(machine);
+
+ e = path_startswith(path, "/machine/");
+ if (!e)
+ return -ENOENT;
+
+ n = strchrnul(e, '/');
+ if (e == n)
+ return -ENOENT;
+
+ s = strndupa(e, n - e);
+
+ r = strdup(cg_unescape(s));
+ if (!r)
+ return -ENOMEM;
+
+ *machine = r;
+ return 0;
+}
+
+int cg_pid_get_machine_name(pid_t pid, char **machine) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(machine);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_machine_name(cgroup, machine);
+}
+
+int cg_path_get_session(const char *path, char **session) {
+ const char *e, *n;
+ char *s;
+
+ assert(path);
+ assert(session);
+
+ e = path_startswith(path, "/user/");
+ if (!e)
+ return -ENOENT;
+
+ /* Skip the user name */
+ e = skip_label(e);
+ if (!e)
+ return -ENOENT;
+
+ n = strchrnul(e, '/');
+ if (n - e < 8)
+ return -ENOENT;
+ if (memcmp(n - 8, ".session", 8) != 0)
+ return -ENOENT;
+
+ s = strndup(e, n - e - 8);
+ if (!s)
+ return -ENOMEM;
+
+ *session = s;
+ return 0;
+}
+
+int cg_pid_get_session(pid_t pid, char **session) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(session);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_session(cgroup, session);
+}
+
+int cg_path_get_owner_uid(const char *path, uid_t *uid) {
+ const char *e, *n;
+ char *s;
+
+ assert(path);
+ assert(uid);
+
+ e = path_startswith(path, "/user/");
+ if (!e)
+ return -ENOENT;
+
+ n = strchrnul(e, '/');
+ if (n - e < 5)
+ return -ENOENT;
+ if (memcmp(n - 5, ".user", 5) != 0)
+ return -ENOENT;
+
+ s = strndupa(e, n - e - 5);
+ if (!s)
+ return -ENOMEM;
+
+ return parse_uid(s, uid);
+}
+
+int cg_pid_get_owner_uid(pid_t pid, uid_t *uid) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ assert(uid);
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_owner_uid(cgroup, uid);
+}
+
+int cg_controller_from_attr(const char *attr, char **controller) {
+ const char *dot;
+ char *c;
+
+ assert(attr);
+ assert(controller);
+
+ if (!filename_is_safe(attr))
+ return -EINVAL;
+
+ dot = strchr(attr, '.');
+ if (!dot) {
+ *controller = NULL;
+ return 0;
+ }
+
+ c = strndup(attr, dot - attr);
+ if (!c)
+ return -ENOMEM;
+
+ if (!cg_controller_is_valid(c, false)) {
+ free(c);
+ return -EINVAL;
+ }
+
+ *controller = c;
+ return 1;
+}
+
+char *cg_escape(const char *p) {
+ bool need_prefix = false;
+
+ /* This implements very minimal escaping for names to be used
+ * as file names in the cgroup tree: any name which might
+ * conflict with a kernel name or is prefixed with '_' is
+ * prefixed with a '_'. That way, when reading cgroup names it
+ * is sufficient to remove a single prefixing underscore if
+ * there is one. */
+
+ /* The return value of this function (unlike cg_unescape())
+ * needs free()! */
+
+ if (p[0] == '_' || streq(p, "notify_on_release") || streq(p, "release_agent") || streq(p, "tasks"))
+ need_prefix = true;
+ else {
+ const char *dot;
+
+ dot = strrchr(p, '.');
+ if (dot) {
+
+ if (dot - p == 6 && memcmp(p, "cgroup", 6) == 0)
+ need_prefix = true;
+ else {
+ char *n;
+
+ n = strndupa(p, dot - p);
+
+ if (check_hierarchy(n) >= 0)
+ need_prefix = true;
+ }
+ }
+ }
+
+ if (need_prefix)
+ return strappend("_", p);
+ else
+ return strdup(p);
+}
+
+char *cg_unescape(const char *p) {
+ assert(p);
+
+ /* The return value of this function (unlike cg_escape())
+ * doesn't need free()! */
+
+ if (p[0] == '_')
+ return (char*) p+1;
+
+ return (char*) p;
+}
+
+#define CONTROLLER_VALID \
+ "0123456789" \
+ "abcdefghijklmnopqrstuvwxyz" \
+ "ABCDEFGHIJKLMNOPQRSTUVWXYZ" \
+ "_"
+
+bool cg_controller_is_valid(const char *p, bool allow_named) {
+ const char *t, *s;
+
+ if (!p)
+ return false;
+
+ if (allow_named) {
+ s = startswith(p, "name=");
+ if (s)
+ p = s;
+ }
+
+ if (*p == 0 || *p == '_')
+ return false;
+
+ for (t = p; *t; t++)
+ if (!strchr(CONTROLLER_VALID, *t))
+ return false;
+
+ if (t - p > FILENAME_MAX)
+ return false;
+
+ return true;