feat: generate kernel module dependency tree

Run `depmod` during install/upgrades when extensions provide kernel
modules and `modules.dep` needs to be re-generated. This also allows
modules of same name from kernel to co-exist. Modules in `extras`
folder takes precedence over `in-built` ones.

Signed-off-by: Noel Georgi <git@frezbo.dev>

Dockerfile

@@ -652,6 +652,7 @@ RUN apk add --no-cache --update --no-scripts \
     bash \
     cpio \
     efibootmgr \
+    kmod \
     mtools \
     qemu-img \
     squashfs-tools \
@@ -663,6 +664,7 @@ ARG TARGETARCH
 ENV TARGETARCH ${TARGETARCH}
 COPY --from=install-artifacts / /
 COPY --from=installer-build /installer /bin/installer
+COPY --chmod=0644 hack/extra-modules.conf /etc/modules.d/10-extra-modules.conf
 RUN ln -s /bin/installer /bin/talosctl
 ARG TAG
 ENV VERSION ${TAG}

cmd/installer/pkg/install/extensions.go

@@ -20,24 +20,36 @@ import (
 	extinterface "github.com/siderolabs/talos/pkg/machinery/extensions"
 )
 
+// nolint:gocyclo
 func (i *Installer) installExtensions() error {
-	extensions, err := extensions.List(constants.SystemExtensionsPath)
+	extensionsList, err := extensions.List(constants.SystemExtensionsPath)
 	if err != nil {
 		return fmt.Errorf("error listing extensions: %w", err)
 	}
 
-	if len(extensions) == 0 {
+	if len(extensionsList) == 0 {
 		return nil
 	}
 
-	if err = printExtensions(extensions); err != nil {
+	if err = printExtensions(extensionsList); err != nil {
 		return err
 	}
 
-	if err = validateExtensions(extensions); err != nil {
+	if err = validateExtensions(extensionsList); err != nil {
 		return err
 	}
 
+	extensionsPathWithKernelModules := findExtensionsWithKernelModules(extensionsList)
+
+	if len(extensionsPathWithKernelModules) > 0 {
+		kernelModuleDepExtension, genErr := extensions.GenerateKernelModuleDependencyTreeExtension(extensionsPathWithKernelModules, i.options.Arch)
+		if genErr != nil {
+			return genErr
+		}
+
+		extensionsList = append(extensionsList, kernelModuleDepExtension)
+	}
+
 	tempDir, err := os.MkdirTemp("", "ext")
 	if err != nil {
 		return err
@@ -47,7 +59,7 @@ func (i *Installer) installExtensions() error {
 
 	var cfg *extinterface.Config
 
-	if cfg, err = compressExtensions(extensions, tempDir); err != nil {
+	if cfg, err = compressExtensions(extensionsList, tempDir); err != nil {
 		return err
 	}
 
@@ -123,6 +135,18 @@ func compressExtensions(extensions []*extensions.Extension, tempDir string) (*ex
 	return cfg, nil
 }
 
+func findExtensionsWithKernelModules(extensions []*extensions.Extension) []string {
+	var modulesPath []string
+
+	for _, ext := range extensions {
+		if ext.ProvidesKernelModules() {
+			modulesPath = append(modulesPath, ext.KernelModuleDirectory())
+		}
+	}
+
+	return modulesPath
+}
+
 func buildContents(path string) (io.Reader, error) {
 	var listing bytes.Buffer
 

go.mod

@@ -112,6 +112,7 @@ require (
 	github.com/spf13/pflag v1.0.5
 	github.com/stretchr/testify v1.8.1
 	github.com/u-root/u-root v0.10.0
+	github.com/ulikunitz/xz v0.5.8
 	github.com/vishvananda/netlink v1.2.1-beta.2
 	github.com/vmware-tanzu/sonobuoy v0.56.14
 	github.com/vmware/govmomi v0.30.0
@@ -243,6 +244,7 @@ require (
 	github.com/opencontainers/selinux v1.10.1 // indirect
 	github.com/pelletier/go-toml/v2 v2.0.6 // indirect
 	github.com/peterbourgon/diskv v2.0.1+incompatible // indirect
+	github.com/pierrec/lz4/v4 v4.1.14 // indirect
 	github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 // indirect
 	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
@@ -263,7 +265,6 @@ require (
 	github.com/spf13/viper v1.14.0 // indirect
 	github.com/subosito/gotenv v1.4.1 // indirect
 	github.com/u-root/uio v0.0.0-20221213070652-c3537552635f // indirect
-	github.com/ulikunitz/xz v0.5.8 // indirect
 	github.com/vishvananda/netns v0.0.0-20210104183010-2eb08e3e575f // indirect
 	github.com/xiang90/probing v0.0.0-20190116061207-43a291ad63a2 // indirect
 	github.com/xlab/treeprint v1.1.0 // indirect

go.sum

@@ -927,6 +927,8 @@ github.com/pelletier/go-toml/v2 v2.0.6 h1:nrzqCb7j9cDFj2coyLNLaZuJTLjWjlaz6nvTvI
 github.com/pelletier/go-toml/v2 v2.0.6/go.mod h1:eumQOmlWiOPt5WriQQqoM5y18pDHwha2N+QD+EUNTek=
 github.com/peterbourgon/diskv v2.0.1+incompatible h1:UBdAOUP5p4RWqPBg048CAvpKN+vxiaj6gdUUzhl4XmI=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
+github.com/pierrec/lz4/v4 v4.1.14 h1:+fL8AQEZtz/ijeNnpduH0bROTu0O3NZAlPjQxGn8LwE=
+github.com/pierrec/lz4/v4 v4.1.14/go.mod h1:gZWDp/Ze/IJXGXf23ltt2EXimqmTUXEy0GFuRQyBid4=
 github.com/pin/tftp v2.1.0+incompatible h1:Yng4J7jv6lOc6IF4XoB5mnd3P7ZrF60XQq+my3FAMus=
 github.com/pin/tftp v2.1.0+incompatible/go.mod h1:xVpZOMCXTy+A5QMjEVN0Glwa1sUvaJhFXbr/aAxuxGY=
 github.com/pkg/browser v0.0.0-20210911075715-681adbf594b8 h1:KoWmjvw+nsYOo29YJK9vDA65RGE3NrOnUtO7a+RF9HU=

hack/extra-modules.conf

@@ -0,0 +1 @@
+search extras built-in

internal/pkg/extensions/extensions.go

@@ -6,6 +6,8 @@
 package extensions
 
 import (
+	"path/filepath"
+
 	"github.com/siderolabs/talos/pkg/machinery/extensions"
 )
 
@@ -16,3 +18,16 @@ type Extension struct {
 	directory  string
 	rootfsPath string
 }
+
+func newExtension(rootfsPath, directory string) *Extension {
+	extension := &Extension{
+		rootfsPath: rootfsPath,
+		directory:  directory,
+	}
+
+	if extension.directory == "" {
+		extension.directory = filepath.Base(rootfsPath)
+	}
+
+	return extension
+}

internal/pkg/extensions/kernel_modules.go

@@ -0,0 +1,240 @@
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+// Package extensions provides function to manage system extensions.
+package extensions
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+
+	"github.com/u-root/u-root/pkg/cpio"
+	"github.com/ulikunitz/xz"
+	"golang.org/x/sys/unix"
+	"gopkg.in/freddierice/go-losetup.v1"
+
+	"github.com/siderolabs/talos/internal/pkg/mount"
+	"github.com/siderolabs/talos/pkg/machinery/constants"
+	"github.com/siderolabs/talos/pkg/machinery/extensions"
+)
+
+// ProvidesKernelModules returns true if the extension provides kernel modules.
+func (ext *Extension) ProvidesKernelModules() bool {
+	if _, err := os.Stat(filepath.Join(ext.rootfsPath, constants.DefaultKernelModulesPath)); os.IsNotExist(err) {
+		return false
+	}
+
+	return true
+}
+
+// KernelModuleDirectory returns the path to the kernel modules directory.
+func (ext *Extension) KernelModuleDirectory() string {
+	return filepath.Join(ext.rootfsPath, constants.DefaultKernelModulesPath)
+}
+
+// GenerateKernelModuleDependencyTreeExtension generates a kernel module dependency tree extension.
+// nolint:gocyclo
+func GenerateKernelModuleDependencyTreeExtension(extensionsPathWithKernelModules []string, arch string) (*Extension, error) {
+	log.Println("preparing to run depmod to generate kernel modules dependency tree")
+
+	tempDir, err := os.MkdirTemp("", "ext-modules")
+	if err != nil {
+		return nil, err
+	}
+
+	defer logErr(func() error {
+		return os.RemoveAll(tempDir)
+	})
+
+	initramfsxz, err := os.Open(fmt.Sprintf(constants.InitramfsAssetPath, arch))
+	if err != nil {
+		return nil, err
+	}
+
+	defer logErr(func() error {
+		return initramfsxz.Close()
+	})
+
+	r, err := xz.NewReader(initramfsxz)
+	if err != nil {
+		return nil, err
+	}
+
+	var buff bytes.Buffer
+
+	if _, err = io.Copy(&buff, r); err != nil {
+		return nil, err
+	}
+
+	tempRootfsFile := filepath.Join(tempDir, constants.RootfsAsset)
+
+	if err = extractRootfsFromInitramfs(buff, tempRootfsFile); err != nil {
+		return nil, err
+	}
+
+	// now we are ready to mount rootfs.sqsh
+	// create a mount point under tempDir
+	rootfsMountPath := filepath.Join(tempDir, "rootfs-mnt")
+
+	// create the loopback device from the squashfs file
+	dev, err := losetup.Attach(tempRootfsFile, 0, true)
+	if err != nil {
+		return nil, err
+	}
+
+	defer logErr(func() error {
+		if err = dev.Detach(); err != nil {
+			return err
+		}
+
+		return dev.Remove()
+	})
+
+	// setup a temporary mount point for the squashfs file and mount it
+	m := mount.NewMountPoint(dev.Path(), rootfsMountPath, "squashfs", unix.MS_RDONLY|unix.MS_I_VERSION, "", mount.WithFlags(mount.ReadOnly|mount.Shared))
+
+	if err = m.Mount(); err != nil {
+		return nil, err
+	}
+
+	defer logErr(func() error {
+		return m.Unmount()
+	})
+
+	// create an overlayfs which contains the rootfs squashfs mount as the base
+	// and the extension modules as subsequent lower directories
+	overlays := mount.NewMountPoints()
+	// writable overlayfs mount inside a container required a tmpfs mount
+	overlays.Set("overlays-tmpfs", mount.NewMountPoint("tmpfs", constants.VarSystemOverlaysPath, "tmpfs", unix.MS_I_VERSION, ""))
+
+	// append the rootfs mount point
+	extensionsPathWithKernelModules = append(extensionsPathWithKernelModules, filepath.Join(rootfsMountPath, constants.DefaultKernelModulesPath))
+
+	// create the overlayfs mount point as read write
+	mp := mount.NewMountPoint("", strings.Join(extensionsPathWithKernelModules, ":"), "", unix.MS_I_VERSION, "", mount.WithFlags(mount.Overlay|mount.Shared))
+	overlays.Set("overlays-mnt", mp)
+
+	if err = mount.Mount(overlays); err != nil {
+		return nil, err
+	}
+
+	defer logErr(func() error {
+		return mount.Unmount(overlays)
+	})
+
+	log.Println("running depmod to generate kernel modules dependency tree")
+
+	if err = depmod(mp.Target()); err != nil {
+		return nil, err
+	}
+
+	// we want this temp directory to be present until the extension is compressed later on, so not removing it here
+	kernelModulesDependencyTreeStagingDir, err := os.MkdirTemp("", "module-deps")
+	if err != nil {
+		return nil, err
+	}
+
+	kernelModulesDepenencyTreeDirectory := filepath.Join(kernelModulesDependencyTreeStagingDir, constants.DefaultKernelModulesPath)
+
+	if err := os.MkdirAll(kernelModulesDepenencyTreeDirectory, 0o755); err != nil {
+		return nil, err
+	}
+
+	if err := findAndMoveKernelModulesDepFiles(kernelModulesDepenencyTreeDirectory, mp.Target()); err != nil {
+		return nil, err
+	}
+
+	kernelModulesDepTreeExtension := newExtension(kernelModulesDependencyTreeStagingDir, "modules.dep")
+	kernelModulesDepTreeExtension.Manifest = extensions.Manifest{
+		Version: constants.DefaultKernelVersion,
+		Metadata: extensions.Metadata{
+			Name:        "modules.dep",
+			Version:     constants.DefaultKernelVersion,
+			Author:      "Talos Machinery",
+			Description: "Combined modules.dep for all extensions",
+		},
+	}
+
+	return kernelModulesDepTreeExtension, nil
+}
+
+func logErr(f func() error) {
+	// if file is already closed, ignore the error
+	if err := f(); !errors.Is(err, os.ErrClosed) {
+		log.Println(err)
+	}
+}
+
+func extractRootfsFromInitramfs(input bytes.Buffer, rootfsFilePath string) error {
+	recReader := cpio.Newc.Reader(bytes.NewReader(input.Bytes()))
+
+	if err := cpio.ForEachRecord(recReader, func(r cpio.Record) error {
+		if r.Name != constants.RootfsAsset {
+			return nil
+		}
+
+		reader := io.NewSectionReader(r.ReaderAt, 0, int64(r.FileSize))
+		f, err := os.Create(rootfsFilePath)
+		if err != nil {
+			return err
+		}
+
+		defer logErr(func() error {
+			return f.Close()
+		})
+
+		_, err = io.Copy(f, reader)
+		if err != nil {
+			return err
+		}
+
+		return f.Close()
+	}); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func depmod(kernelModulesPath string) error {
+	baseDir := strings.TrimSuffix(kernelModulesPath, constants.DefaultKernelModulesPath)
+
+	cmd := exec.Command("depmod", "--all", "--basedir", baseDir, "--config", "/etc/modules.d/10-extra-modules.conf", constants.DefaultKernelVersion)
+	cmd.Stderr = os.Stderr
+
+	return cmd.Run()
+}
+
+func findAndMoveKernelModulesDepFiles(dest, kernelModulesPath string) error {
+	fs, err := os.ReadDir(kernelModulesPath)
+	if err != nil {
+		return err
+	}
+
+	for _, f := range fs {
+		if f.IsDir() {
+			continue
+		}
+
+		if strings.HasPrefix(f.Name(), "modules.") {
+			fs, err := f.Info()
+			if err != nil {
+				return err
+			}
+
+			if err := moveFile(fs, filepath.Join(kernelModulesPath, f.Name()), filepath.Join(dest, f.Name())); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}

pkg/machinery/constants/constants.go

@@ -15,6 +15,9 @@ const (
 	// DefaultKernelVersion is the default Linux kernel version.
 	DefaultKernelVersion = "6.1.4-talos"
 
+	// DefaultKernelModulesPath is the default path to the kernel modules.
+	DefaultKernelModulesPath = "/lib/modules" + "/" + DefaultKernelVersion
+
 	// KernelParamConfig is the kernel parameter name for specifying the URL.
 	// to the config.
 	KernelParamConfig = "talos.config"