diff --git a/include/osmocom/core/fsm.h b/include/osmocom/core/fsm.h
index c9e1e0c..41d01a5 100644
--- a/include/osmocom/core/fsm.h
+++ b/include/osmocom/core/fsm.h
@@ -220,6 +220,7 @@
 
 int osmo_fsm_inst_update_id(struct osmo_fsm_inst *fi, const char *id);
 int osmo_fsm_inst_update_id_f(struct osmo_fsm_inst *fi, const char *fmt, ...);
+int osmo_fsm_inst_update_id_f_sanitize(struct osmo_fsm_inst *fi, char replace_with, const char *fmt, ...);
 
 const char *osmo_fsm_event_name(struct osmo_fsm *fsm, uint32_t event);
 const char *osmo_fsm_inst_name(struct osmo_fsm_inst *fi);
diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h
index 08735fd..f27359c 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -140,6 +140,7 @@
 
 bool osmo_identifier_valid(const char *str);
 bool osmo_separated_identifiers_valid(const char *str, const char *sep_chars);
+void osmo_identifier_sanitize_buf(char *str, const char *sep_chars, char replace_with);
 
 const char *osmo_escape_str(const char *str, int len);
 char *osmo_escape_str_buf2(char *buf, size_t bufsize, const char *str, int in_len);