fix(pkg/driverbuilder): properly export KERNELDIR in kernel-download scripts

pkg/driverbuilder/builder/templates/alinux_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/almalinux_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/amazonlinux_kernel.sh

@@ -35,4 +35,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/archlinux_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/lib/modules/*/build/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/centos_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/debian_kernel.sh

@@ -38,4 +38,4 @@ sourcedir=$(find . -type d -name "{{ .KernelHeadersPattern }}" | head -n 1 | xar
 sed -i 's/\/usr\/src/../g' $sourcedir/Makefile
 
 # exit value
-echo $sourcedir
+export KERNELDIR=$sourcedir

pkg/driverbuilder/builder/templates/fedora_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/flatcar_kernel.sh

@@ -39,4 +39,4 @@ make KCONFIG_CONFIG=/tmp/kernel.config oldconfig
 make KCONFIG_CONFIG=/tmp/kernel.config modules_prepare
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/opensuse_kernel.sh

@@ -34,4 +34,4 @@ cd /tmp/kernel-download/usr/src
 sourcedir="$(find . -type d -name "linux-*-obj" | head -n 1 | xargs readlink -f)/*/default"
 
 # exit value
-echo $sourcedir
+export KERNELDIR=$sourcedir

pkg/driverbuilder/builder/templates/oracle_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/photonos_kernel.sh

@@ -35,4 +35,4 @@ mkdir -p /tmp/kernel
 mv usr/src/linux-*headers-*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/redhat_kernel.sh

@@ -34,4 +34,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/rocky_kernel.sh

@@ -32,4 +32,4 @@ mkdir -p /tmp/kernel
 mv usr/src/kernels/*/* /tmp/kernel
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/builder/templates/sles_kernel.sh

@@ -35,4 +35,4 @@ done
 sourcedir="$(find . -type d -name "linux-*-obj" | head -n 1 | xargs readlink -f)/*/default"
 
 # exit value
-echo $sourcedir
+export KERNELDIR=$sourcedir

pkg/driverbuilder/builder/templates/ubuntu_kernel.sh

@@ -34,4 +34,4 @@ cd /tmp/kernel-download/usr/src/
 sourcedir=$(find . -type d -name "{{ .KernelHeadersPattern }}" | head -n 1 | xargs readlink -f)
 
 # exit value
-echo $sourcedir
+export KERNELDIR=$sourcedir

pkg/driverbuilder/builder/templates/vanilla_kernel.sh

@@ -47,4 +47,4 @@ make KCONFIG_CONFIG=/tmp/kernel.config prepare
 make KCONFIG_CONFIG=/tmp/kernel.config modules_prepare
 
 # exit value
-echo /tmp/kernel
+export KERNELDIR=/tmp/kernel

pkg/driverbuilder/docker.go

@@ -233,6 +233,13 @@ func (bp *DockerBuildProcessor) Start(b *builder.Build) error {
 		return err
 	}
 
+	// We make all 3 scripts executables,
+	// then:
+	// * download libs at required version
+	// * download and extract headers
+	//   * each download-headers script will export KERNELDIR variable internally
+	//   * we source download-headers.sh so that KERNELDIR is then visible to driverkit.sh
+	// * we finally make the actual build of the drivers
 	runCmd :=
 		`
 #!/bin/bash
@@ -242,7 +249,8 @@ chmod +x /driverkit/download-headers.sh
 chmod +x /driverkit/driverkit.sh
 
 /driverkit/download-libs.sh
-KERNELDIR=$(/driverkit/download-headers.sh) /driverkit/driverkit.sh
+. /driverkit/download-headers.sh
+/driverkit/driverkit.sh
 `
 
 	files := []dockerCopyFile{

pkg/driverbuilder/kubernetes.go

@@ -113,9 +113,9 @@ func (bp *KubernetesBuildProcessor) buildModule(b *builder.Build) error {
 	}
 
 	// We run a script that downloads libs,
-	// download and extracts kernelURLs saving its output to KERNELDIR env variable,
+	// then downloads and extracts kernelURLs exporting KERNELDIR env variable,
 	// then finally runs the build script.
-	res = fmt.Sprintf("%s\nexport KERNELDIR=$(%s)\n%s", libsDownloadScript, kernelDownloadScript, res)
+	res = fmt.Sprintf("%s\n%s\n%s", libsDownloadScript, kernelDownloadScript, res)
 
 	if c.ModuleFilePath != "" {
 		res = fmt.Sprintf("%s\n%s", "touch "+moduleLockFile, res)

pkg/driverbuilder/local.go

@@ -2,6 +2,7 @@ package driverbuilder
 
 import (
 	"bufio"
+	"bytes"
 	"context"
 	_ "embed"
 	"errors"
@@ -13,7 +14,6 @@ import (
 	"os/exec"
 	"os/user"
 	"path/filepath"
-	"strings"
 	"time"
 )
 
@@ -67,24 +67,35 @@ func (lbp *LocalBuildProcessor) Start(b *builder.Build) error {
 		// if an unsupported target is passed.
 		// Go on skipping automatic kernel headers download.
 		if err == nil {
-			slog.Info("Trying automatic kernel headers download.")
+			slog.Info("Trying automatic kernel headers download")
 			kernelDownloadScript, err := builder.KernelDownloadScript(realBuilder, nil, kr)
+			// Patch kernel download script to echo KERNELDIR.
+			// We need to capture KERNELDIR to later pass it as env variable to the build.
+			kernelDownloadScript += "\necho $KERNELDIR"
 			if err == nil {
 				out, err := exec.Command("bash", "-c", kernelDownloadScript).Output()
 				if err == nil {
-					path := strings.TrimSuffix(string(out), "\n")
+					// Scan all stdout line by line and
+					// store last line as KERNELDIR path.
+					reader := bytes.NewReader(out)
+					scanner := bufio.NewScanner(reader)
+					var path string
+					for scanner.Scan() {
+						path = scanner.Text()
+					}
+					slog.Info("Setting KERNELDIR env var", "path", path)
 					// add the kerneldir path to env
 					lbp.envMap[kernelDirEnv] = path
 					defer func() {
 						_ = os.RemoveAll("/tmp/kernel-download")
 						_ = os.RemoveAll(path)
 					}()
 				} else {
-					slog.Warn("Failed to download headers.", "err", err)
+					slog.Warn("Failed to download headers", "err", err)
 				}
 			}
 		} else {
-			slog.Info("Skipping kernel headers automatic download.", "err", err)
+			slog.Info("Skipping kernel headers automatic download", "err", err)
 		}
 	}
 
@@ -137,7 +148,7 @@ func (lbp *LocalBuildProcessor) Start(b *builder.Build) error {
 	srcProbePath := vv.GetProbeFullPath(c)
 
 	if len(lbp.srcDir) == 0 {
-		slog.Info("Downloading driver sources.")
+		slog.Info("Downloading driver sources")
 		// Download src!
 		libsDownloadScript, err := builder.LibsDownloadScript(c)
 		if err != nil {
@@ -168,14 +179,14 @@ func (lbp *LocalBuildProcessor) Start(b *builder.Build) error {
 
 		stdout, err := cmd.StdoutPipe()
 		if err != nil {
-			slog.Warn("Failed to pipe stdout. Trying without piping.", "err", err)
+			slog.Warn("Failed to pipe stdout", "err", err)
 			_, err = cmd.CombinedOutput()
 		} else {
 			cmd.Stderr = cmd.Stdout // redirect stderr to stdout so that we catch it
 			defer stdout.Close()
 			err = cmd.Start()
 			if err != nil {
-				slog.Warn("Failed to execute command.", "err", err)
+				slog.Warn("Failed to execute command", "err", err)
 			} else {
 				// print the output of the subprocess line by line
 				scanner := bufio.NewScanner(stdout)