chore(pkg/driver,cmd/driver): small updates.

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

cmd/driver/prepare/prepare.go

@@ -43,7 +43,7 @@ type driverPrepareOptions struct {
 	*options.Common
 	*options.Driver
 	Download            bool
-	Build               bool
+	Compile             bool
 	DriverVersion       string
 	DriverKernelRelease string
 	DriverKernelVersion string
@@ -57,7 +57,7 @@ func NewDriverPrepareCmd(ctx context.Context, opt *options.Common) *cobra.Comman
 		Driver: &options.Driver{},
 		// Defaults to downloading or building if needed
 		Download: true,
-		Build:    true,
+		Compile:  true,
 	}
 
 	cmd := &cobra.Command{
@@ -71,8 +71,8 @@ func NewDriverPrepareCmd(ctx context.Context, opt *options.Common) *cobra.Comman
 	}
 
 	output.ExitOnErr(o.Printer, o.Driver.AddFlags(cmd))
-	cmd.Flags().BoolVar(&o.Download, "download", true, "Whether to enable download of drivers")
-	cmd.Flags().BoolVar(&o.Build, "build", true, "Whether to enable build of drivers")
+	cmd.Flags().BoolVar(&o.Download, "download", true, "Whether to enable download of prebuilt drivers")
+	cmd.Flags().BoolVar(&o.Compile, "compile", true, "Whether to enable local compilation of drivers")
 	cmd.Flags().StringVar(&o.DriverVersion, "driver-version", "", "Driver version to be built")
 	//nolint:lll // no need to check for line length.
 	cmd.Flags().StringVar(&o.DriverKernelRelease, "driver-kernelrelease", "", "Specify the kernel release for which to download/build the driver in the same format used by 'uname -r' (e.g. '6.1.0-10-cloud-amd64')")
@@ -114,18 +114,25 @@ func (o *driverPrepareOptions) RunDriverPrepare(_ context.Context, _ []string) e
 		"driver version", o.DriverVersion,
 		"driver type", driver.Type,
 		"driver name", o.Name,
+		"compile", o.Compile,
+		"download", o.Download,
 		"arch", info.Architecture.ToNonDeb(),
 		"kernel release", info.String(),
 		"kernel version", info.KernelVersion))
 
 	if !driver.Type.HasArtifacts() {
-		o.Printer.Logger.Info("no artifacts needed")
+		o.Printer.Logger.Info("No artifacts needed for the selected driver.")
+		return nil
+	}
+
+	if !o.Download && !o.Compile {
+		o.Printer.Logger.Info("Nothing to do: download and compile disabled.")
 		return nil
 	}
 
 	d, err := driverdistro.DiscoverDistro(info, o.HostRoot)
 	if err != nil {
-		if errors.Is(err, driverdistro.ErrUnsupported) && o.Build {
+		if errors.Is(err, driverdistro.ErrUnsupported) && o.Compile {
 			o.Download = false
 			o.Printer.Logger.Info("Detected an unsupported target system, please get in touch with the Falco community. Trying to compile anyway.")
 		} else {
@@ -142,33 +149,33 @@ func (o *driverPrepareOptions) RunDriverPrepare(_ context.Context, _ []string) e
 	setDefaultHTTPClientOpts(o.driverDownloadOptions)
 
 	var dest string
+	defer func() {
+		// We don't care about errors at this stage
+		// Fallback: try to load any available driver if leaving with an error.
+		// It is only useful for kmod, as it will try to
+		// modprobe a pre-existent version of the driver,
+		// hoping it will be compatible.
+		_ = driver.Type.Load(o.Printer, dest, err != nil)
+	}()
+
 	if o.Download {
 		dest, err = driverdistro.Download(d, o.Printer, info, o.Name, driver.Type, o.DriverVersion, o.DriverRepos)
 		if err == nil {
-			// We don't care about errors at this stage
-			_ = driver.Type.Load(o.Printer, dest, false)
 			return nil
 		}
 		// Print the error but go on
 		// attempting a build if requested
 		o.Printer.Logger.Error(err.Error())
 	}
 
-	if o.Build {
+	if o.Compile {
 		dest, err = driverdistro.Build(d, o.Printer)
 		if err == nil {
-			// We don't care about errors
-			_ = driver.Type.Load(o.Printer, dest, false)
+			return nil
 		}
-	}
-
-	if err != nil {
 		o.Printer.Logger.Error(err.Error())
-		// Fallback: try to load any available driver.
-		// It is only useful for kmod, as it will try to
-		// modprobe a pre-existent version of the driver,
-		// hoping it will be compatible.
-		_ = driver.Type.Load(o.Printer, o.Name, true)
 	}
-	return fmt.Errorf("last error: %w", err)
+
+	dest = o.Name // used by deferred function above
+	return fmt.Errorf("failed: %w", err)
 }

pkg/driver/distro/distro.go

@@ -110,15 +110,15 @@ func getOSReleaseDistro(kr *kernelrelease.KernelRelease, hostRoot string) (Distr
 	return distro, nil
 }
 
-func toURL(repo, driverVer, fileName string, kr *kernelrelease.KernelRelease) string {
-	return fmt.Sprintf("%s/%s/%s/%s", repo, driverVer, kr.Architecture.ToNonDeb(), fileName)
+func toURL(repo, driverVer, fileName, arch string) string {
+	return fmt.Sprintf("%s/%s/%s/%s", repo, driverVer, arch, fileName)
 }
 
-func toLocalPath(driverVer, fileName string, kr *kernelrelease.KernelRelease) string {
-	return fmt.Sprintf("%s/.falco/%s/%s/%s", homedir.Get(), driverVer, kr.Architecture.ToNonDeb(), fileName)
+func toLocalPath(driverVer, fileName, arch string) string {
+	return fmt.Sprintf("%s/.falco/%s/%s/%s", homedir.Get(), driverVer, arch, fileName)
 }
 
-func driverToFilename(d Distro, kr *kernelrelease.KernelRelease, driverName string, driverType drivertype.DriverType) string {
+func toFilename(d Distro, kr *kernelrelease.KernelRelease, driverName string, driverType drivertype.DriverType) string {
 	// Fixup kernel information before attempting to download
 	fixedKR := d.fixupKernel(*kr)
 	return fmt.Sprintf("%s_%s_%s_%s%s", driverName, d, fixedKR.String(), fixedKR.KernelVersion, driverType.Extension())
@@ -143,9 +143,9 @@ func Download(d Distro,
 	driverType drivertype.DriverType,
 	driverVer string, repos []string,
 ) (string, error) {
-	driverFileName := driverToFilename(d, &kr, driverName, driverType)
+	driverFileName := toFilename(d, &kr, driverName, driverType)
 	// Skip if existent
-	destination := toLocalPath(driverVer, driverFileName, &kr)
+	destination := toLocalPath(driverVer, driverFileName, kr.Architecture.ToNonDeb())
 	f, err := os.Open(destination) //nolint:gosec // false positive
 	if err == nil {
 		_ = f.Close()
@@ -156,7 +156,7 @@ func Download(d Distro,
 	// Try to download from any specified repository,
 	// stopping at first successful http GET.
 	for _, repo := range repos {
-		url := toURL(repo, driverVer, driverFileName, &kr)
+		url := toURL(repo, driverVer, driverFileName, kr.Architecture.ToNonDeb())
 		printer.Logger.Info("Trying to download a driver", printer.Logger.Args("url", url))
 
 		resp, err := http.Get(url) //nolint:gosec,noctx // false positive

pkg/driver/kernel/kernel.go

@@ -37,9 +37,8 @@ func FetchInfo(enforcedKR, enforcedKV string) (kernelrelease.KernelRelease, erro
 			return kernelrelease.KernelRelease{}, err
 		}
 
-		// Take eg: "#1 SMP PREEMPT_DYNAMIC Tue, 10 Oct 2023 21:10:21 +0000" and return "1".
-		kv = string(bytes.Trim(u.Version[:], "\x00"))
 		kr = string(bytes.Trim(u.Release[:], "\x00"))
+		kv = string(bytes.Trim(u.Version[:], "\x00"))
 	} else {
 		kr = enforcedKR
 		kv = enforcedKV
@@ -52,6 +51,7 @@ func FetchInfo(enforcedKR, enforcedKV string) (kernelrelease.KernelRelease, erro
 
 // formatVersion takes a kernelversion string (as taken from `uname -v`
 // and extracts the first part of the string.
+// Eg: '#1 SMP PREEMPT_DYNAMIC Tue, 10 Oct 2023 21:10:21 +0000' -> '1'.
 // Eg: '#26~22.04.1-Ubuntu SMP Mon Apr 24 01:58:15 UTC 2023' -> '26~22.04.1-Ubuntu'.
 func formatVersion(kv string) string {
 	// Take eg: "#1 SMP PREEMPT_DYNAMIC Tue, 10 Oct 2023 21:10:21 +0000" and return "1".

pkg/driver/type/kmod.go

@@ -134,7 +134,7 @@ func (k *kmod) Load(printer *output.Printer, driverName string, fallback bool) e
 		if err == nil {
 			printer.Logger.Info("Success: module found and loaded with modprobe.")
 		} else {
-			printer.Logger.Error("Consider compiling your own driver and loading it or getting in touch with the Falco community.")
+			printer.Logger.Warn("Consider compiling your own driver and loading it or getting in touch with the Falco community.")
 		}
 		return err
 	}