cmd/mbf: expose some artifacts for curing

This will remain until dist is successfully bootstrapped.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -136,6 +136,37 @@ func main() {
 		},
 	)
 
+	c.NewCommand(
+		"cure",
+		"Cure the named artifact and show its path",
+		func(args []string) error {
+			if len(args) != 1 {
+				return errors.New("cure requires 1 argument")
+			}
+			var a pkg.Artifact
+			switch args[0] {
+			case "busybox":
+				a = rosa.Std.NewBusybox()
+			case "musl":
+				a = rosa.Std.NewMusl(nil)
+			case "go":
+				a = rosa.Std.NewGo()
+			case "rsync":
+				a = rosa.Std.NewRsync()
+
+			default:
+				return fmt.Errorf("unsupported artifact %q", args[0])
+			}
+
+			pathname, _, err := cache.Cure(a)
+			if err == nil {
+				log.Println(pathname)
+			}
+			return err
+
+		},
+	)
+
 	c.MustParse(os.Args[1:], func(err error) {
 		if cache != nil {
 			cache.Close()