+ assert(path);
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, 1, &p);
+ if (r < 0)
+ return r;
+
+ e = endswith(p, "/" SPECIAL_SYSTEM_SLICE);
+ if (e)
+ *e = 0;
+
+ *path = p;
+ return 0;
+}
+
+int cg_shift_path(const char *cgroup, const char *root, const char **shifted) {
+ _cleanup_free_ char *rt = NULL;
+ char *p;
+ int r;
+
+ assert(cgroup);
+ assert(shifted);
+
+ if (!root) {
+ /* If the root was specified let's use that, otherwise
+ * let's determine it from PID 1 */
+
+ r = cg_get_root_path(&rt);
+ if (r < 0)
+ return r;
+
+ root = rt;
+ }
+
+ p = path_startswith(cgroup, root);
+ if (p)
+ *shifted = p - 1;
+ else
+ *shifted = cgroup;
+
+ return 0;
+}
+
+int cg_pid_get_path_shifted(pid_t pid, const char *root, char **cgroup) {
+ _cleanup_free_ char *raw = NULL;
+ const char *c;
+ int r;
+
+ assert(pid >= 0);
+ assert(cgroup);
+
+ r = cg_pid_get_path(SYSTEMD_CGROUP_CONTROLLER, pid, &raw);
+ if (r < 0)
+ return r;
+
+ r = cg_shift_path(raw, root, &c);
+ if (r < 0)
+ return r;
+
+ if (c == raw) {
+ *cgroup = raw;
+ raw = NULL;
+ } else {
+ char *n;
+
+ n = strdup(c);
+ if (!n)
+ return -ENOMEM;
+
+ *cgroup = n;
+ }
+
+ return 0;
+}
+
+int cg_path_decode_unit(const char *cgroup, char **unit){
+ char *e, *c, *s;
+
+ assert(cgroup);
+ assert(unit);
+
+ e = strchrnul(cgroup, '/');
+ c = strndupa(cgroup, e - cgroup);
+ c = cg_unescape(c);
+
+ if (!unit_name_is_valid(c, TEMPLATE_INVALID))
+ return -EINVAL;
+
+ s = strdup(c);
+ if (!s)
+ return -ENOMEM;
+
+ *unit = s;
+ return 0;
+}
+
+static const char *skip_slices(const char *p) {
+ /* Skips over all slice assignments */
+
+ for (;;) {
+ size_t n;
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (n <= 6 || memcmp(p + n - 6, ".slice", 6) != 0)
+ return p;
+
+ p += n;
+ }
+}
+
+int cg_path_get_unit(const char *path, char **unit) {
+ const char *e;
+
+ assert(path);
+ assert(unit);
+
+ e = skip_slices(path);
+
+ 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);
+}
+
+/**
+ * Skip session-*.scope, but require it to be there.
+ */
+static const char *skip_session(const char *p) {
+ size_t n;
+
+ assert(p);
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (n < strlen("session-x.scope") || memcmp(p, "session-", 8) != 0 || memcmp(p + n - 6, ".scope", 6) != 0)
+ return NULL;
+
+ p += n;
+ p += strspn(p, "/");
+
+ return p;
+}
+
+/**
+ * Skip user@*.service, but require it to be there.
+ */
+static const char *skip_user_manager(const char *p) {
+ size_t n;
+
+ assert(p);
+
+ p += strspn(p, "/");
+
+ n = strcspn(p, "/");
+ if (n < strlen("user@x.service") || memcmp(p, "user@", 5) != 0 || memcmp(p + n - 8, ".service", 8) != 0)
+ return NULL;
+
+ p += n;
+ p += strspn(p, "/");
+
+ return p;
+}
+
+int cg_path_get_user_unit(const char *path, char **unit) {
+ const char *e, *t;
+
+ 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 */
+
+ /* Skip slices, if there are any */
+ e = skip_slices(path);
+
+ /* Skip the session scope... */
+ t = skip_session(e);
+ if (t)
+ /* ... and skip more slices if there's one */
+ e = skip_slices(t);
+ else {
+ /* ... or require a user manager unit to be there */
+ e = skip_user_manager(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) {
+ _cleanup_free_ char *u = NULL, *sl = NULL;
+ int r;
+
+ r = cg_path_get_unit(path, &u);
+ if (r < 0)
+ return r;
+
+ sl = strjoin("/run/systemd/machines/unit:", u, NULL);
+ if (!sl)
+ return -ENOMEM;
+
+ return readlink_malloc(sl, machine);
+}
+
+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);