+int session_create_fifo(Session *s) {
+ int r;
+
+ assert(s);
+
+ /* Create FIFO */
+ if (!s->fifo_path) {
+ r = safe_mkdir("/run/systemd/sessions", 0755, 0, 0);
+ if (r < 0)
+ return r;
+
+ if (asprintf(&s->fifo_path, "/run/systemd/sessions/%s.ref", s->id) < 0)
+ return -ENOMEM;
+
+ if (mkfifo(s->fifo_path, 0600) < 0 && errno != EEXIST)
+ return -errno;
+ }
+
+ /* Open reading side */
+ if (s->fifo_fd < 0) {
+ struct epoll_event ev;
+
+ s->fifo_fd = open(s->fifo_path, O_RDONLY|O_CLOEXEC|O_NDELAY);
+ if (s->fifo_fd < 0)
+ return -errno;
+
+ r = hashmap_put(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1), s);
+ if (r < 0)
+ return r;
+
+ zero(ev);
+ ev.events = 0;
+ ev.data.u32 = FD_FIFO_BASE + s->fifo_fd;
+
+ if (epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_ADD, s->fifo_fd, &ev) < 0)
+ return -errno;
+ }
+
+ /* Open writing side */
+ r = open(s->fifo_path, O_WRONLY|O_CLOEXEC|O_NDELAY);
+ if (r < 0)
+ return -errno;
+
+ return r;
+}
+
+void session_remove_fifo(Session *s) {
+ assert(s);
+
+ if (s->fifo_fd >= 0) {
+ assert_se(hashmap_remove(s->manager->fifo_fds, INT_TO_PTR(s->fifo_fd + 1)) == s);
+ assert_se(epoll_ctl(s->manager->epoll_fd, EPOLL_CTL_DEL, s->fifo_fd, NULL) == 0);
+ close_nointr_nofail(s->fifo_fd);
+ s->fifo_fd = -1;
+ }
+
+ if (s->fifo_path) {
+ unlink(s->fifo_path);
+ free(s->fifo_path);
+ s->fifo_path = NULL;
+ }
+}
+
+int session_check_gc(Session *s, bool drop_not_started) {