+static void spawn_ask_password_agent(void) {
+ pid_t parent, child;
+
+ /* We check STDIN here, not STDOUT, since this is about input,
+ * not output */
+ if (!isatty(STDIN_FILENO))
+ return;
+
+ if (!arg_ask_password)
+ return;
+
+ parent = getpid();
+
+ /* Spawns a temporary TTY agent, making sure it goes away when
+ * we go away */
+
+ if ((child = fork()) < 0)
+ return;
+
+ if (child == 0) {
+ /* In the child */
+
+ const char * const args[] = {
+ SYSTEMD_TTY_ASK_PASSWORD_AGENT_BINARY_PATH,
+ "--watch",
+ NULL
+ };
+
+ if (prctl(PR_SET_PDEATHSIG, SIGTERM) < 0)
+ _exit(EXIT_FAILURE);
+
+ /* Check whether our parent died before we were able
+ * to set the death signal */
+ if (getppid() != parent)
+ _exit(EXIT_SUCCESS);
+
+ execv(args[0], (char **) args);
+ _exit(EXIT_FAILURE);
+ }
+}
+