+ *session = r;
+ }
+
+ return 0;
+}
+
+int cg_pid_get_session(pid_t pid, char **session) {
+ _cleanup_free_ char *cgroup = NULL;
+ int r;
+
+ r = cg_pid_get_path_shifted(pid, NULL, &cgroup);
+ if (r < 0)
+ return r;
+
+ return cg_path_get_session(cgroup, session);
+}
+
+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] == 0 ||
+ p[0] == '_' ||
+ 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 \
+ DIGITS LETTERS \
+ "_"
+
+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;
+}
+
+int cg_set_attribute(const char *controller, const char *path, const char *attribute, const char *value) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, attribute, &p);
+ if (r < 0)
+ return r;
+
+ return write_string_file_no_create(p, value);
+}
+
+int cg_get_attribute(const char *controller, const char *path, const char *attribute, char **ret) {
+ _cleanup_free_ char *p = NULL;
+ int r;
+
+ r = cg_get_path(controller, path, attribute, &p);
+ if (r < 0)
+ return r;
+
+ return read_one_line_file(p, ret);
+}
+
+static const char mask_names[] =
+ "cpu\0"
+ "cpuacct\0"
+ "blkio\0"
+ "memory\0"
+ "devices\0";
+
+int cg_create_everywhere(CGroupControllerMask supported, CGroupControllerMask mask, const char *path) {
+ CGroupControllerMask bit = 1;
+ const char *n;
+ int r;
+
+ /* This one will create a cgroup in our private tree, but also
+ * duplicate it in the trees specified in mask, and remove it
+ * in all others */
+
+ /* First create the cgroup in our own hierarchy. */
+ r = cg_create(SYSTEMD_CGROUP_CONTROLLER, path);
+ if (r < 0)
+ return r;
+
+ /* Then, do the same in the other hierarchies */
+ NULSTR_FOREACH(n, mask_names) {
+ if (mask & bit)
+ cg_create(n, path);
+ else if (supported & bit)
+ cg_trim(n, path, true);
+
+ bit <<= 1;