From f878c9ddbdb8bade9822b8b578f6641c054a9bc9 Mon Sep 17 00:00:00 2001
From: Colin Walters <walters@verbum.org>
Date: Wed, 11 Oct 2023 20:28:10 -0400
Subject: [PATCH] Add optionally-installed grub2 code

This pairs with https://github.com/coreos/bootupd/pull/543
Basically we want bootupd to take care of installing this.  Add
the config here (where it more closely arguably belongs) so
that it can be optionally installed.

My proposal for at least the Fedora packaging of Ignition
is that we unconditionally depend on bootupd and install this,
because there's no one there using Ignition who doesn't want bootupd.
---
 Makefile              |  3 +++
 docs/release-notes.md |  2 ++
 grub2/ignition.cfg    | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+)
 create mode 100644 grub2/ignition.cfg

diff --git a/Makefile b/Makefile
index 3fe8bbb27..546586247 100644
--- a/Makefile
+++ b/Makefile
@@ -30,6 +30,9 @@ install: all
 	ln -sf ../lib/dracut/modules.d/30ignition/ignition $(DESTDIR)/usr/libexec/ignition-apply
 	ln -sf ../lib/dracut/modules.d/30ignition/ignition $(DESTDIR)/usr/libexec/ignition-rmcfg
 
+install-grub-for-bootupd:
+	install -m 0644 -D -t $(DESTDIR)/usr/lib/bootupd/grub2-static/configs.d grub2/ignition.cfg
+
 .PHONY: vendor
 vendor:
 	@go mod vendor
diff --git a/docs/release-notes.md b/docs/release-notes.md
index 6cf20fa57..3411ac062 100644
--- a/docs/release-notes.md
+++ b/docs/release-notes.md
@@ -12,6 +12,8 @@ nav_order: 9
 ### Features
 
 - Support Hetzner Cloud
+- A GRUB configuration suitable for use with https://github.com/coreos/bootupd
+  can now be installed; use `make install-grub-for-bootupd` to install it
 
 ### Changes
 
diff --git a/grub2/ignition.cfg b/grub2/ignition.cfg
new file mode 100644
index 000000000..8334b5c26
--- /dev/null
+++ b/grub2/ignition.cfg
@@ -0,0 +1,19 @@
+# This GRUB config snippet implements the `ignition.firstboot` semantic using a
+# stamp file in the bootfs. This is used at least on CoreOS-based systems where
+# it's injected by https://github.com/coreos/bootupd.
+
+# Determine if this is a first boot and set the ${ignition_firstboot} variable
+# which is used in the kernel command line.
+set ignition_firstboot=""
+if [ -f "/ignition.firstboot" ]; then
+    # Default networking parameters to be used with Ignition.
+    set ignition_network_kcmdline=''
+
+    # Source in the `ignition.firstboot` file which could override the
+    # above $ignition_network_kcmdline with static networking config.
+    # This override feature is also used by coreos-installer to persist static
+    # networking config provided during install to the first boot of the machine.
+    source "/ignition.firstboot"
+
+    set ignition_firstboot="ignition.firstboot ${ignition_network_kcmdline}"
+fi