new(cmd,pkg): added new local command to build local kernel using l…

…ocal kernel sources / gccs / clang.

Signed-off-by: Federico Di Pierro <[email protected]>

cmd/config_options.go

@@ -24,7 +24,7 @@ import (
 	"github.com/go-playground/validator/v10"
 )
 
-var validProcessors = []string{"docker", "kubernetes", "kubernetes-in-cluster"}
+var validProcessors = []string{"docker", "kubernetes", "kubernetes-in-cluster", "local"}
 var aliasProcessors = []string{"docker", "k8s", "k8s-ic"}
 var configOptions *ConfigOptions
 

cmd/local.go

@@ -0,0 +1,84 @@
+package cmd
+
+import (
+	"bytes"
+	"github.com/falcosecurity/driverkit/pkg/driverbuilder"
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"github.com/spf13/viper"
+	"golang.org/x/sys/unix"
+	"log/slog"
+	"os"
+	"runtime"
+	"strings"
+)
+
+// NewLocalCmd creates the `driverkit local` command.
+func NewLocalCmd(rootCommand *RootCmd, rootOpts *RootOptions, rootFlags *pflag.FlagSet) *cobra.Command {
+	localCmd := &cobra.Command{
+		Use:               "local",
+		Short:             "Build Falco kernel modules and eBPF probes in local env with local kernel sources and gcc/clang.",
+		PersistentPreRunE: persistentPreRunFunc(rootCommand, rootOpts),
+		Run: func(c *cobra.Command, args []string) {
+			slog.With("processor", c.Name()).Info("driver building, it will take a few seconds")
+			if !configOptions.DryRun {
+				b := rootOpts.ToBuild()
+				if !b.HasOutputs() {
+					return
+				}
+				if err := driverbuilder.NewLocalBuildProcessor(viper.GetInt("timeout")).Start(b); err != nil {
+					slog.With("err", err.Error()).Error("exiting")
+					os.Exit(1)
+				}
+			}
+		},
+	}
+	// Add root flags, but not the ones unneeded
+	unusedFlagsSet := map[string]struct{}{
+		"architecture":        {},
+		"kernelrelease":       {},
+		"kernelversion":       {},
+		"target":              {},
+		"kernelurls":          {},
+		"builderrepo":         {},
+		"builderimage":        {},
+		"gccversion":          {},
+		"kernelconfigdata":    {},
+		"proxy":               {},
+		"registry-name":       {},
+		"registry-password":   {},
+		"registry-plain-http": {},
+		"registry-user":       {},
+	}
+	flagSet := pflag.NewFlagSet("local", pflag.ExitOnError)
+	rootFlags.VisitAll(func(flag *pflag.Flag) {
+		if _, ok := unusedFlagsSet[flag.Name]; !ok {
+			flagSet.AddFlag(flag)
+		}
+	})
+	localCmd.PersistentFlags().AddFlagSet(flagSet)
+	return localCmd
+}
+
+// Partially overrides rootCmd.persistentPreRunFunc setting some defaults before config init/validation stage.
+func persistentPreRunFunc(rootCommand *RootCmd, rootOpts *RootOptions) func(c *cobra.Command, args []string) error {
+	return func(c *cobra.Command, args []string) error {
+		// Default values
+		rootOpts.Target = "local"
+		u := unix.Utsname{}
+		if err := unix.Uname(&u); err != nil {
+			slog.Error("failed to retrieve default uname values", "err", err)
+			// this only affects logs!
+			rootOpts.KernelRelease = "1.0.0"
+			rootOpts.KernelVersion = "1"
+		} else {
+			rootOpts.KernelRelease = string(bytes.Trim(u.Release[:], "\x00"))
+			kv := string(bytes.Trim(u.Version[:], "\x00"))
+			kv = strings.Trim(kv, "#")
+			kv = strings.Split(kv, " ")[0]
+			rootOpts.KernelVersion = kv
+		}
+		rootOpts.Architecture = runtime.GOARCH
+		return rootCommand.c.PersistentPreRunE(c, args)
+	}
+}

cmd/root.go

@@ -184,6 +184,7 @@ func NewRootCmd() *RootCmd {
 	rootCmd.AddCommand(NewKubernetesCmd(rootOpts, flags))
 	rootCmd.AddCommand(NewKubernetesInClusterCmd(rootOpts, flags))
 	rootCmd.AddCommand(NewDockerCmd(rootOpts, flags))
+	rootCmd.AddCommand(NewLocalCmd(ret, rootOpts, flags))
 	rootCmd.AddCommand(NewImagesCmd(rootOpts, flags))
 	rootCmd.AddCommand(NewCompletionCmd())
 

cmd/testdata/autohelp.txt

@@ -1,4 +1,4 @@
-level=INFO msg="specify a valid processor" processors="[docker kubernetes kubernetes-in-cluster]"
+level=INFO msg="specify a valid processor" processors="[docker kubernetes kubernetes-in-cluster local]"
 {{ .Desc }}
 
 {{ .Usage }}

cmd/testdata/templates/commands.txt

@@ -4,4 +4,5 @@ Available Commands:
   help                  Help about any command
   images                List builder images
   kubernetes            Build Falco kernel modules and eBPF probes against a Kubernetes cluster.
-  kubernetes-in-cluster Build Falco kernel modules and eBPF probes against a Kubernetes cluster inside a Kubernetes cluster.
+  kubernetes-in-cluster Build Falco kernel modules and eBPF probes against a Kubernetes cluster inside a Kubernetes cluster.
+  local                 Build Falco kernel modules and eBPF probes in local env with local kernel sources and gcc/clang.

pkg/driverbuilder/builder/builders.go

@@ -86,12 +86,12 @@ func Script(b Builder, c Config, kr kernelrelease.KernelRelease) (string, error)
 		return "", err
 	}
 
+	var urls []string
 	minimumURLs := 1
 	if bb, ok := b.(MinimumURLsBuilder); ok {
 		minimumURLs = bb.MinimumURLs()
 	}
 
-	var urls []string
 	if c.KernelUrls == nil {
 		urls, err = b.URLs(kr)
 		if err != nil {
@@ -250,10 +250,17 @@ func (b *Build) GetBuilderImage() string {
 
 // Factory returns a builder for the given target.
 func Factory(target Type) (Builder, error) {
+	// Workaround for "local" target (that is not exposed to users,
+	// nor registered in byTarget map)".
+	if target.String() == "local" {
+		return &LocalBuilder{}, nil
+	}
+
 	// Driverkit builder is named "ubuntu"; there is no ubuntu-foo
 	if strings.HasPrefix(target.String(), "ubuntu") {
 		target = Type("ubuntu")
 	}
+
 	b, ok := byTarget[target]
 	if !ok {
 		return nil, fmt.Errorf("no builder found for target: %s", target)

pkg/driverbuilder/builder/local.go

@@ -0,0 +1,53 @@
+package builder
+
+import (
+	_ "embed"
+	"fmt"
+	"github.com/falcosecurity/driverkit/pkg/kernelrelease"
+)
+
+// NOTE: since this is only used by local build,
+// it is not exposed in `target` array,
+// so no init() function to register it is present.
+
+//go:embed templates/local.sh
+var localTemplate string
+
+type LocalBuilder struct {
+	GccPath string
+}
+
+func (l *LocalBuilder) Name() string {
+	return "local"
+}
+
+func (l *LocalBuilder) TemplateScript() string {
+	return localTemplate
+}
+
+func (l *LocalBuilder) URLs(kr kernelrelease.KernelRelease) ([]string, error) {
+	return nil, nil
+}
+
+func (l *LocalBuilder) MinimumURLs() int {
+	// We don't need any url
+	return 0
+}
+
+type localTemplateData struct {
+	commonTemplateData
+}
+
+func (l *LocalBuilder) TemplateData(c Config, _ kernelrelease.KernelRelease, _ []string) interface{} {
+	return localTemplateData{
+		commonTemplateData: commonTemplateData{
+			DriverBuildDir:    DriverDirectory,
+			ModuleDownloadURL: fmt.Sprintf("%s/%s.tar.gz", c.DownloadBaseURL, c.DriverVersion),
+			ModuleDriverName:  c.DriverName,
+			ModuleFullPath:    ModuleFullPath,
+			BuildModule:       len(c.ModuleFilePath) > 0,
+			BuildProbe:        len(c.ProbeFilePath) > 0,
+			GCCVersion:        l.GccPath,
+		},
+	}
+}

pkg/driverbuilder/builder/templates/local.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+# SPDX-License-Identifier: Apache-2.0
+#
+# Copyright (C) 2023 The Falco Authors.
+#
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# Simple script that desperately tries to load the kernel instrumentation by
+# looking for it in a bunch of ways. Convenient when running Falco inside
+# a container or in other weird environments.
+#
+set -xeuo pipefail
+
+rm -Rf {{ .DriverBuildDir }}
+mkdir {{ .DriverBuildDir }}
+rm -Rf /tmp/module-download
+mkdir -p /tmp/module-download
+
+curl --silent -SL {{ .ModuleDownloadURL }} | tar -xzf - -C /tmp/module-download
+mv /tmp/module-download/*/driver/* {{ .DriverBuildDir }}
+
+cp /tmp/module-Makefile {{ .DriverBuildDir }}/Makefile
+bash /tmp/fill-driver-config.sh {{ .DriverBuildDir }}
+
+{{ if .BuildModule }}
+# Build the module
+cd {{ .DriverBuildDir }}
+make CC={{ .GCCVersion }}
+mv {{ .ModuleDriverName }}.ko {{ .ModuleFullPath }}
+strip -g {{ .ModuleFullPath }}
+# Print results
+modinfo {{ .ModuleFullPath }}
+{{ end }}
+
+{{ if .BuildProbe }}
+# Build the eBPF probe
+cd {{ .DriverBuildDir }}/bpf
+make
+ls -l probe.o
+{{ end }}
+
+rm -Rf /tmp/module-download