From aa8839d0728a7d2936a13041c7fb13eca09e2788 Mon Sep 17 00:00:00 2001
From: Stephen Lowrie <slowrie@redhat.com>
Date: Mon, 15 Mar 2021 23:23:13 -0500
Subject: [PATCH] examples: add ignition-kargs binary example

---
 examples/ignition-kargs-helper  | 45 +++++++++++++++++++++++++++++++++
 examples/ignition-kargs.service | 22 ++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100755 examples/ignition-kargs-helper
 create mode 100644 examples/ignition-kargs.service

diff --git a/examples/ignition-kargs-helper b/examples/ignition-kargs-helper
new file mode 100755
index 0000000000..460e8f2b91
--- /dev/null
+++ b/examples/ignition-kargs-helper
@@ -0,0 +1,45 @@
+#!/bin/bash
+
+set -euxo pipefail
+
+# Mount /boot. Note that we mount /boot but we don't unmount it because we
+# are run in a systemd unit with MountFlags=slave so it is unmounted for us.
+bootmnt=/mnt/boot_partition
+mkdir -p ${bootmnt}
+bootdev=/dev/disk/by-label/boot
+mount -o rw ${bootdev} ${bootmnt}
+grubcfg="${bootmnt}/grub/grub.cfg"
+
+kernelopts="$(grep kernelopts= <$grubcfg)"
+
+while [[ $# -gt 0 ]]
+do
+key="$1"
+
+case $key in
+--should-exist)
+    arg="$2"
+    # don't repeat the arg
+    if [[ ! " ${kernelopts[*]} " =~ " ${arg} " ]]; then
+        kernelopts="$kernelopts $arg "
+    fi
+    shift 2
+    ;;
+--should-not-exist)
+    arg="$2"
+    kernelopts="$(echo "$kernelopts" | sed "s|$2||g")"
+    shift 2
+    ;;
+    *)
+    echo "Unknown option"
+    exit 1
+    ;;
+esac
+done
+
+# only apply the changes & reboot if changes have been made
+if [[ ! "$kernelopts" == "$(grep kernelopts= <$grubcfg)" ]]; then
+    awk "{sub(/kernelopts=.*/,\"$kernelopts\"); print}" $grubcfg > tmp && mv tmp $grubcfg
+
+    systemctl reboot
+fi
diff --git a/examples/ignition-kargs.service b/examples/ignition-kargs.service
new file mode 100644
index 0000000000..75cbb39a10
--- /dev/null
+++ b/examples/ignition-kargs.service
@@ -0,0 +1,22 @@
+[Unit]
+Description=Ignition (kargs)
+Documentation=https://github.com/coreos/ignition
+ConditionPathExists=/etc/initrd-release
+DefaultDependencies=false
+Before=ignition-complete.target
+
+# Stage order: setup -> fetch-offline [-> fetch] [-> kargs] -> disks -> mount -> files.
+After=ignition-fetch.service
+Before=ignition-disks.service
+
+OnFailure=emergency.target
+OnFailureJobMode=isolate
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+EnvironmentFile=/run/ignition.env
+ExecStart=/usr/bin/ignition --root=/sysroot --platform=${PLATFORM_ID} --stage=kargs
+# MountFlags=slave is so the umount of /boot is guaranteed to happen.
+# /boot will only be mounted for the lifetime of the unit.
+MountFlags=slave