Add "rd.cmdline=ask" kernel command line parameter

prompts the user for additional kernel command line parameters

dracut.cmdline.7.asc

@@ -86,6 +86,9 @@ rootfstype=ext3
     was built on. This helps booting, if any disk layout changed, especially in
     combination with rd.auto or other parameters specifying the layout.
 
+**rd.cmdline=ask**::
+    prompts the user for additional kernel command line parameters
+
 **rd.fstab=0**::
     do not honor special mount options for the root filesystem found in
     _/etc/fstab_ of the real root.

modules.d/98systemd/dracut-cmdline-ask.service

@@ -0,0 +1,33 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+
+# See systemd.special(7) for details
+
+[Unit]
+Description=dracut ask for additional cmdline parameters
+DefaultDependencies=no
+Before=dracut-cmdline.service
+After=systemd-journald.socket
+Wants=systemd-journald.socket
+ConditionPathExists=/etc/initrd-release
+ConditionKernelCommandLine=rd.cmdline=ask
+
+[Service]
+Environment=DRACUT_SYSTEMD=1
+Environment=NEWROOT=/sysroot
+Type=oneshot
+ExecStart=-/bin/dracut-cmdline-ask
+StandardInput=tty
+StandardOutput=inherit
+StandardError=inherit
+RemainAfterExit=yes
+KillMode=process
+IgnoreSIGPIPE=no
+
+# Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash
+# terminates cleanly.
+KillSignal=SIGHUP

modules.d/98systemd/dracut-cmdline-ask.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+# -*- mode: shell-script; indent-tabs-mode: nil; sh-basic-offset: 4; -*-
+# ex: ts=8 sw=4 sts=4 et filetype=sh
+
+sleep 0.5
+echo
+sleep 0.5
+echo
+sleep 0.5
+echo
+echo
+echo
+echo
+echo "Enter additional kernel command line parameter (end with ctrl-d or .)"
+while read -e -p "> " line; do
+    [[ "$line" == "." ]] && break
+    [[ "$line" ]] && printf -- "%s\n" "$line" >> /etc/cmdline.d/99-cmdline-ask.conf
+done
+
+exit 0

modules.d/98systemd/dracut-cmdline.sh

@@ -11,7 +11,9 @@ type getarg >/dev/null 2>&1 || . /lib/dracut-lib.sh
 [ -n "$VERSION" ] && info "dracut-$VERSION"
 
 if ! getargbool 1 'rd.hostonly'; then
+    [ -f /etc/cmdline.d/99-cmdline-ask.conf ] && mv /etc/cmdline.d/99-cmdline-ask.conf /tmp/99-cmdline-ask.conf
     remove_hostonly_files
+    [ -f /tmp/99-cmdline-ask.conf ] && mv /tmp/99-cmdline-ask.conf /etc/cmdline.d/99-cmdline-ask.conf
 fi
 
 info "Using kernel command line parameters:"

modules.d/98systemd/module-setup.sh

@@ -187,6 +187,7 @@ install() {
     ln_r "${systemdsystemunitdir}/initrd.target" "${systemdsystemunitdir}/default.target"
 
     inst_script "$moddir/dracut-cmdline.sh" /bin/dracut-cmdline
+    inst_script "$moddir/dracut-cmdline-ask.sh" /bin/dracut-cmdline-ask
     inst_script "$moddir/dracut-pre-udev.sh" /bin/dracut-pre-udev
     inst_script "$moddir/dracut-pre-trigger.sh" /bin/dracut-pre-trigger
     inst_script "$moddir/dracut-initqueue.sh" /bin/dracut-initqueue
@@ -216,6 +217,7 @@ install() {
     mkdir -p "${initdir}/$systemdsystemunitdir/initrd.target.wants"
     for i in \
         dracut-cmdline.service \
+        dracut-cmdline-ask.service \
         dracut-initqueue.service \
         dracut-mount.service \
         dracut-pre-mount.service \

modules.d/99base/init.sh

@@ -112,6 +112,14 @@ fi
 
 source_conf /etc/conf.d
 
+if getarg "rd.cmdline=ask"; then
+    echo "Enter additional kernel command line parameter (end with ctrl-d or .)"
+    while read -p "> " line; do
+        [ "$line" = "." ] && break
+        echo "$line" >> /etc/cmdline.d/99-cmdline-ask.conf
+    done
+fi
+
 if ! getargbool 1 'rd.hostonly'; then
     remove_hostonly_files
 fi