fix(mod): probe searches for features built-in the kernel

internal/mod/builtin_linux.go

@@ -0,0 +1,33 @@
+package mod
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+var errBuiltinModuleNotFound = errors.New("builtin module not found")
+
+func checkModulesBuiltin(modulesPath, moduleName string) error {
+	f, err := os.Open(filepath.Join(modulesPath, "modules.builtin"))
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	moduleName = strings.TrimSuffix(moduleName, ".ko")
+
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		line := scanner.Text()
+		line = strings.TrimSuffix(line, ".ko")
+		if strings.HasSuffix(line, "/"+moduleName) {
+			return nil
+		}
+	}
+
+	return fmt.Errorf("%w: %s", errBuiltinModuleNotFound, moduleName)
+}