bake: handle root evaluation with available drives for windows entitlement

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

bake/entitlements_windows.go

@@ -0,0 +1,39 @@
+package bake
+
+import (
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+)
+
+func evaluatePaths(in []string) ([]string, error) {
+	out := make([]string, 0, len(in))
+	for _, p := range in {
+		if p == "/" {
+			out = append(out, getAllVolumes()...)
+			continue
+		}
+		v, err := filepath.Abs(p)
+		if err != nil {
+			return nil, err
+		}
+		v, err = filepath.EvalSymlinks(v)
+		if err != nil {
+			return nil, errors.Wrapf(err, "failed to evaluate path %q", p)
+		}
+		out = append(out, v)
+	}
+	return out, nil
+}
+
+func getAllVolumes() []string {
+	var volumes []string
+	for _, drive := range "ABCDEFGHIJKLMNOPQRSTUVWXYZ" {
+		p := string(drive) + ":" + string(filepath.Separator)
+		if _, err := os.Stat(p); !os.IsNotExist(err) {
+			volumes = append(volumes, p)
+		}
+	}
+	return volumes
+}