From f037f6d1bdb893ab94a5fcfffdcb158720fbf138 Mon Sep 17 00:00:00 2001
From: Peter Georg <peter.georg@physik.uni-regensburg.de>
Date: Jul 22 2021 11:21:31 +0000
Subject: Improve handling kernel versions


* Add auto-detection for latest (installed) kernel version
* Allow setting minimum kernel version supported
* Allow setting a particular kernel version

---

diff --git a/SPECS/kmod-wireguard.spec b/SPECS/kmod-wireguard.spec
index 662a5b2..6083728 100644
--- a/SPECS/kmod-wireguard.spec
+++ b/SPECS/kmod-wireguard.spec
@@ -1,6 +1,16 @@
 %global pkg wireguard
 
-%global kernel_version 4.18.0-315.el8
+%global kernel_version_min 4.18.0-315.el8
+
+# To pick a specific kernel use `--define "kernel_version 4.18.0-315.el8"`
+# Otherwise the later version of %%{kernel_version_min} and the 'latest'
+# installed version of kernel-devel will be used.
+
+%global kernel_version_latest %({ echo %{kernel_version_min}; rpm --query kernel-devel --queryformat '%%{VERSION}-%%{RELEASE}\\\n' | grep -v kernel-devel; } | sort -V | sed -e '0,/^%{kernel_version_min}$/d' | tail -n 1)
+
+%if "%{kernel_version_latest}" != ""
+%{!?kernel_version:%{expand:%%global kernel_version %{kernel_version_latest}}}
+%endif
 
 %global _use_internal_dependency_generator 0
 
@@ -32,20 +42,29 @@ ExclusiveArch:    x86_64 aarch64
 BuildRequires:    elfutils-libelf-devel
 BuildRequires:    gcc
 BuildRequires:    kernel-abi-whitelists
-BuildRequires:    kernel-devel = %{kernel_version}
 BuildRequires:    kernel-rpm-macros
 BuildRequires:    kmod
 BuildRequires:    make
 BuildRequires:    redhat-rpm-config
 BuildRequires:    xz
 
+%{!?kernel_version:
+BuildRequires:    kernel-devel >= %{kernel_version_min}
+}
+
+%{?kernel_version:
+BuildRequires:    kernel-devel = %{kernel_version}
+
 Supplements:      kernel = %{kernel_version}
 
 Requires:         (kernel = %{kernel_version} if kernel)
+
+Provides:         kernel-modules = %{kernel_version}.%{_arch}
+}
+
 Requires(post):   /usr/sbin/depmod
 Requires(postun): /usr/sbin/depmod
 
-Provides:         kernel-modules = %{kernel_version}.%{_arch}
 Provides:         %{name} = %{?epoch:%{epoch}:}%{version}-%{release}
 
 Supplements:      wireguard-tools