fix(pkg,internal): multiple fixes related to cos and driver build.

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

internal/utils/extract.go

@@ -58,7 +58,7 @@ func ExtractTarGz(gzipStream io.Reader, destDir string, stripPathComponents int)
 		switch header.Typeflag {
 		case tar.TypeDir:
 			d := filepath.Join(destDir, strippedName)
-			if err = os.Mkdir(filepath.Clean(d), 0o750); err != nil {
+			if err = os.MkdirAll(filepath.Clean(d), 0o750); err != nil {
 				return nil, err
 			}
 			files = append(files, d)
@@ -76,8 +76,22 @@ func ExtractTarGz(gzipStream io.Reader, destDir string, stripPathComponents int)
 			if err = outFile.Close(); err != nil {
 				return nil, err
 			}
+			if err = os.Chmod(filepath.Clean(f), header.FileInfo().Mode()); err != nil {
+				return nil, err
+			}
 			files = append(files, f)
-
+		case tar.TypeLink, tar.TypeSymlink:
+			strippedSrcName := stripComponents(header.Linkname, stripPathComponents)
+			fDst := filepath.Join(destDir, strippedName)
+			if header.Typeflag == tar.TypeSymlink {
+				err = os.Symlink(filepath.Clean(strippedSrcName), filepath.Clean(fDst))
+			} else {
+				err = os.Link(filepath.Clean(strippedSrcName), filepath.Clean(fDst))
+			}
+			if err != nil {
+				return nil, err
+			}
+			files = append(files, fDst)
 		default:
 			return nil, fmt.Errorf("extractTarGz: uknown type: %b in %s", header.Typeflag, header.Name)
 		}
@@ -96,5 +110,5 @@ func stripComponents(headerName string, stripComponents int) string {
 	if len(names) < stripComponents {
 		return headerName
 	}
-	return filepath.Clean(strings.Join(names[stripComponents:], "/"))
+	return filepath.Clean(strings.Join(names[stripComponents:], string(os.PathSeparator)))
 }

pkg/driver/distro/cos.go

@@ -18,6 +18,7 @@ package driverdistro
 import (
 	"fmt"
 	"os"
+	"path/filepath"
 
 	"github.com/blang/semver"
 	"github.com/falcosecurity/driverkit/pkg/kernelrelease"
@@ -76,15 +77,15 @@ func (c *cos) customizeBuild(ctx context.Context,
 
 	currKernelDir := env[kernelDirEnv]
 
-	cosKernelDir := currKernelDir + "usr/src/"
+	cosKernelDir := filepath.Join(currKernelDir, "usr", "src")
 	entries, err := os.ReadDir(cosKernelDir)
 	if err != nil {
 		return nil, err
 	}
 	if len(entries) == 0 {
 		return nil, fmt.Errorf("no COS kernel src found")
 	}
-	cosKernelDir = entries[0].Name()
+	cosKernelDir = filepath.Join(cosKernelDir, entries[0].Name())
 	// Override env key
 	env[kernelDirEnv] = cosKernelDir
 

pkg/driver/distro/distro.go

@@ -17,7 +17,7 @@
 package driverdistro
 
 import (
-	"archive/tar"
+	"compress/gzip"
 	"errors"
 	"fmt"
 	"io"
@@ -336,12 +336,17 @@ func downloadKernelSrc(ctx context.Context,
 	if err != nil {
 		return nil, err
 	}
-	var src io.Reader
+	var src io.ReadCloser
 	if strings.HasSuffix(kernelConfigPath, ".gz") {
-		src = tar.NewReader(f)
+		src, err = gzip.NewReader(f)
+		if err != nil {
+			return env, err
+		}
 	} else {
 		src = f
 	}
+	defer src.Close()
+
 	fStat, err := f.Stat()
 	if err != nil {
 		return nil, err

pkg/driver/type/bpf.go

@@ -87,6 +87,7 @@ func (b *bpf) Build(ctx context.Context,
 	makeCmdArgs := fmt.Sprintf(`make -C %q`, filepath.Clean(srcPath))
 	makeCmd := exec.CommandContext(ctx, "bash", "-c", makeCmdArgs) //nolint:gosec // false positive
 	// Append requested env variables to the command env
+	makeCmd.Env = os.Environ()
 	for key, val := range env {
 		makeCmd.Env = append(makeCmd.Env, fmt.Sprintf("%s=%s", key, val))
 	}