systemd: show status when run with plymouth, and don't start plymouth a second time when it is already running

src/main.c

@@ -985,6 +985,11 @@ int main(int argc, char *argv[]) {
         if (parse_argv(argc, argv) < 0)
                 goto finish;
 
+        /* If Plymouth is being run make sure we show the status, so
+         * that there's something nice to see when people press Esc */
+        if (access("/dev/.systemd/plymouth", F_OK) >= 0)
+                arg_show_status = true;
+
         if (arg_action == ACTION_HELP) {
                 retval = help();
                 goto finish;

units/plymouth-start.service

@@ -12,7 +12,13 @@ Wants=systemd-ask-password-plymouth.path
 After=systemd-vconsole-setup.service udev-settle.service
 Before=systemd-ask-password-plymouth.service
 
+# Dracut informs us with this flag file if plymouth is already running
+ConditionPathExists=!/dev/.systemd/plymouth
+
 [Service]
 ExecStart=/sbin/plymouthd --mode=boot
 ExecStartPost=-/bin/plymouth --show-splash
 Type=forking
+
+# Send SIGRTMIN+20 to systemd, i.e. enable status messages
+ExecStartPost=-/usr/bin/kill -54 1