From 18d5de0d0ceb5db146c7a868b4b06afd4ca637c9 Mon Sep 17 00:00:00 2001
From: Daniel Zatovic <daniel.zatovic@gmail.com>
Date: Thu, 29 May 2025 15:57:12 +0200
Subject: [PATCH] build_library: Fix depmod issues with sysext kmods

OS-dependent sysexts that ship kernel modules, usually also ship the
files in /usr/lib/modules/*-flatcar/modules.XXX When multiple such
sysexts get activated, depmod files from just one sysext win and other
kernel modules cannot be loaded using modprobe. We get around this by
removing the depmod files from every sysext with kernel modules.
Instead, we set up modprobe hook, which dynamically runs depmod in a
temporary directory on every sysext kernel module activation.

Signed-off-by: Daniel Zatovic <daniel.zatovic@gmail.com>
---
 .../sysext_mangle_flatcar-nvidia-drivers-535  | 14 ++++++
 ...ext_mangle_flatcar-nvidia-drivers-535-open |  1 +
 .../sysext_mangle_flatcar-nvidia-drivers-550  |  1 +
 ...ext_mangle_flatcar-nvidia-drivers-550-open |  1 +
 .../sysext_mangle_flatcar-nvidia-drivers-570  |  1 +
 ...ext_mangle_flatcar-nvidia-drivers-570-open |  1 +
 build_library/sysext_mangle_flatcar-zfs       |  4 ++
 build_library/sysext_mangle_kmod              | 48 +++++++++++++++++++
 8 files changed, 71 insertions(+)
 create mode 100755 build_library/sysext_mangle_flatcar-nvidia-drivers-535
 create mode 120000 build_library/sysext_mangle_flatcar-nvidia-drivers-535-open
 create mode 120000 build_library/sysext_mangle_flatcar-nvidia-drivers-550
 create mode 120000 build_library/sysext_mangle_flatcar-nvidia-drivers-550-open
 create mode 120000 build_library/sysext_mangle_flatcar-nvidia-drivers-570
 create mode 120000 build_library/sysext_mangle_flatcar-nvidia-drivers-570-open
 create mode 100644 build_library/sysext_mangle_kmod

diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-535 b/build_library/sysext_mangle_flatcar-nvidia-drivers-535
new file mode 100755
index 00000000000..40cb56d05c6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-535
@@ -0,0 +1,14 @@
+#!/bin/bash
+
+set -euo pipefail
+
+SCRIPT_NAME=$(basename "$(realpath "${BASH_SOURCE[0]}")")
+SYSEXT_NAME=${SCRIPT_NAME#sysext_mangle_}
+SYSEXT_NAME=${SYSEXT_NAME%.sh}
+DIR=$(dirname "$(realpath "${BASH_SOURCE[0]}")")
+. "$DIR/sysext_mangle_kmod"
+
+rootfs="${1}"
+
+cd "${rootfs}"
+configure_modprobe "$SYSEXT_NAME"
diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-535-open b/build_library/sysext_mangle_flatcar-nvidia-drivers-535-open
new file mode 120000
index 00000000000..25e899f70a6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-535-open
@@ -0,0 +1 @@
+sysext_mangle_flatcar-nvidia-drivers-535
\ No newline at end of file
diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-550 b/build_library/sysext_mangle_flatcar-nvidia-drivers-550
new file mode 120000
index 00000000000..25e899f70a6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-550
@@ -0,0 +1 @@
+sysext_mangle_flatcar-nvidia-drivers-535
\ No newline at end of file
diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-550-open b/build_library/sysext_mangle_flatcar-nvidia-drivers-550-open
new file mode 120000
index 00000000000..25e899f70a6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-550-open
@@ -0,0 +1 @@
+sysext_mangle_flatcar-nvidia-drivers-535
\ No newline at end of file
diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-570 b/build_library/sysext_mangle_flatcar-nvidia-drivers-570
new file mode 120000
index 00000000000..25e899f70a6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-570
@@ -0,0 +1 @@
+sysext_mangle_flatcar-nvidia-drivers-535
\ No newline at end of file
diff --git a/build_library/sysext_mangle_flatcar-nvidia-drivers-570-open b/build_library/sysext_mangle_flatcar-nvidia-drivers-570-open
new file mode 120000
index 00000000000..25e899f70a6
--- /dev/null
+++ b/build_library/sysext_mangle_flatcar-nvidia-drivers-570-open
@@ -0,0 +1 @@
+sysext_mangle_flatcar-nvidia-drivers-535
\ No newline at end of file
diff --git a/build_library/sysext_mangle_flatcar-zfs b/build_library/sysext_mangle_flatcar-zfs
index 13e9135b3c7..e9ffdb11861 100755
--- a/build_library/sysext_mangle_flatcar-zfs
+++ b/build_library/sysext_mangle_flatcar-zfs
@@ -3,6 +3,9 @@
 set -euo pipefail
 rootfs="${1}"
 
+DIR="$(dirname "$(realpath "${BASH_SOURCE[0]}")")"
+. "$DIR/sysext_mangle_kmod"
+
 pushd "${rootfs}"
 
 rm -rf ./usr/{lib/debug/,lib64/cmake/,include/}
@@ -40,4 +43,5 @@ cat <<EOF >./usr/lib/systemd/system/systemd-udevd.service.d/10-zfs.conf
 [Unit]
 After=systemd-sysext.service
 EOF
+configure_modprobe flatcar-zfs
 popd
diff --git a/build_library/sysext_mangle_kmod b/build_library/sysext_mangle_kmod
new file mode 100644
index 00000000000..b00d48914a6
--- /dev/null
+++ b/build_library/sysext_mangle_kmod
@@ -0,0 +1,48 @@
+#!/bin/bash
+
+configure_modprobe() {
+  local sysext_name="${1}"
+  shift
+
+  local module_directories=(./usr/lib/modules/*-flatcar/)
+
+  mkdir -p ./usr/lib/modprobe.d/
+  for module_name in $(find "${module_directories[@]}" -type f \( -name "*.ko" -o -name "*.ko.*" \) -printf "%f\n" | sed -E 's/\.ko(\.\w+)?$//'); do
+    cat <<EOF >> "./usr/lib/modprobe.d/10-${sysext_name}-kmod-sysext.conf"
+install $module_name     /usr/local/bin/_${sysext_name}_modprobe_helper $module_name
+remove  $module_name     /usr/local/bin/_${sysext_name}_modprobe_helper -r $module_name
+EOF
+  done
+
+  mkdir -p ./usr/local/bin/
+  install -m0755 -D /dev/stdin "./usr/local/bin/_${sysext_name}_modprobe_helper" <<'EOF'
+#!/bin/bash
+
+set -euo pipefail
+
+action="Loading"
+for arg in "$@"; do
+    if [[ $arg == "-r" ]]; then
+        action="Unloading"
+    fi
+done
+echo "$action kernel module from a sysext..."
+
+KMOD_PATH=/usr/lib/modules/$(uname -r)
+TMP_DIR=$(mktemp -d)
+trap "rm -rf -- '${TMP_DIR}'" EXIT
+mkdir "${TMP_DIR}"/{upper,work}
+
+unshare -m bash -s -- "${@}" <<FOE
+set -euo pipefail
+if ! mountpoint -q "${KMOD_PATH}"; then
+    mount -t overlay overlay -o lowerdir="${KMOD_PATH}",upperdir="${TMP_DIR}"/upper,workdir="${TMP_DIR}"/work "${KMOD_PATH}"
+    depmod
+fi
+modprobe --ignore-install "\${@}"
+FOE
+EOF
+
+  # prevent the sysext from masking /usr/lib/modules/*-flatcar/modules.XXX
+  find "${module_directories[@]}" -maxdepth 1 -mindepth 1 -type f -delete
+}