From 20ca44dc7fcf2fc88eea35c551bebeaac1026cf2 Mon Sep 17 00:00:00 2001
From: Maximilian Luz <luzmaximilian@gmail.com>
Date: Fri, 2 Jun 2023 20:56:45 +0200
Subject: [PATCH] contrib/fedora-default-kernel: Make more robust and add
 rEFInd support

Add a script to explicitly handle multiple Surface kernel versions being
installed in parallel, sorting kernels by timestamp and choosing the
latest one.

Further, add support for rEFInd by updating the vmlinuz file timestamp
to ensure it's always seen as the last modified file (which will be
picked by rEFInd as the "default" kernel in that directory).

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---
 contrib/fedora-default-kernel/README.md       |  2 ++
 .../default-kernel.service                    |  2 +-
 .../fedora-default-kernel/default-kernel.sh   | 20 +++++++++++++++++++
 3 files changed, 23 insertions(+), 1 deletion(-)
 create mode 100755 contrib/fedora-default-kernel/default-kernel.sh

diff --git a/contrib/fedora-default-kernel/README.md b/contrib/fedora-default-kernel/README.md
index 68dfe71bf..d4736e045 100644
--- a/contrib/fedora-default-kernel/README.md
+++ b/contrib/fedora-default-kernel/README.md
@@ -12,6 +12,8 @@ selection every time.
 ```bash
 $ sudo dnf install /usr/sbin/grubby
 $ sudo cp default-kernel.{path,service} /etc/systemd/system/
+$ sudo cp default-kernel.sh /usr/local/bin/default-kernel
+$ sudo chmod 755 /usr/local/bin/default-kernel
 $ sudo systemctl daemon-reload
 $ sudo systemctl enable --now default-kernel.path
 ```
diff --git a/contrib/fedora-default-kernel/default-kernel.service b/contrib/fedora-default-kernel/default-kernel.service
index e809019f3..e19d65b61 100644
--- a/contrib/fedora-default-kernel/default-kernel.service
+++ b/contrib/fedora-default-kernel/default-kernel.service
@@ -3,4 +3,4 @@ Description=linux-surface default kernel watchdog
 
 [Service]
 Type=oneshot
-ExecStart=/bin/sh -c "grubby --set-default /boot/vmlinuz*surface*"
+ExecStart=/usr/local/bin/default-kernel
diff --git a/contrib/fedora-default-kernel/default-kernel.sh b/contrib/fedora-default-kernel/default-kernel.sh
new file mode 100755
index 000000000..818b3479c
--- /dev/null
+++ b/contrib/fedora-default-kernel/default-kernel.sh
@@ -0,0 +1,20 @@
+#!/bin/bash
+set -euo pipefail
+
+# get list of surface kernels with timestamp
+kernels=$(find /boot -maxdepth 1 -name "vmlinuz-*.surface.*" -printf '%T@\t%p\n')
+
+# sort by timestamp
+kernels=$(echo "${kernels}" | sort -n)
+
+# get latest kernel (last line) and extract path
+kernel=$(echo "${kernels}" | tail -n1 | cut -f2)
+
+echo $kernel
+
+# update GRUB config
+grubby --set-default "${kernel}"
+
+# update timestamp for rEFInd (ensure it's marked as latest across all kernels,
+# not just surface ones)
+touch "${kernel}"