diff --git a/include/getopt.h b/include/getopt.h
index f23175fb8..4f48ba8fd 100644
--- a/include/getopt.h
+++ b/include/getopt.h
@@ -35,7 +35,7 @@ extern char *optarg;
  * - options can be mixed with nonoptions (like ls /bin -R)
  */
 
-int getopt(int argc, char *argv[], char *optstring);
+int getopt(int argc, char *argv[], const char *optstring);
 
 struct getopt_context {
 	int opterr;
diff --git a/lib/getopt.c b/lib/getopt.c
index ead915099..fd12a886e 100644
--- a/lib/getopt.c
+++ b/lib/getopt.c
@@ -56,10 +56,10 @@ void getopt_context_restore(struct getopt_context *gc)
 }
 EXPORT_SYMBOL(getopt_context_restore);
 
-int getopt(int argc, char *argv[], char *optstring)
+int getopt(int argc, char *argv[], const char *optstring)
 {
 	char curopt;   /* current option character */
-	char *curoptp; /* pointer to the current option in optstring */
+	const char *curoptp; /* pointer to the current option in optstring */
 
 	while(1) {
 		debug("optindex: %d nonopts: %d optind: %d\n", optindex, nonopts, optind);