add identifier sanitation for setting FSM instance ids

We often compose FSM instance IDs from context information, for example placing
an MSISDN string or IP:port information in the FSM instance id, using
osmo_fsm_inst_update_id_f(). This fails if any characters are contained that
don't pass osmo_identifier_valid(). Hence it is the task of the caller to make
sure only characters allowed in an FSM id are applied.

Provide API to trivially allow this by replacing illegal chars:
- osmo_identifier_sanitize_buf(), with access to the same set of illegal
  characters defined in utils.c,
- osmo_fsm_inst_update_id_f_sanitize() implicitly replaces non-identifier
  chars.

This makes it easy to add strings like '192.168.0.1:2342' or '+4987654321' to
an FSM instance id, without adding string mangling to each place that sets an
id; e.g. replacing with '-' to yield '192-168-0-1:2342' or '-4987654321'.

Change-Id: Ia40a6f3b2243c95fe428a080b938e11d8ab771a7

2 files changed, 2 insertions, 0 deletions

diff --git a/include/osmocom/core/fsm.h b/include/osmocom/core/fsm.h
index c9e1e0cf..41d01a58 100644
--- a/include/osmocom/core/fsm.h
+++ b/include/osmocom/core/fsm.h
@@ -220,6 +220,7 @@ void osmo_fsm_inst_free(struct osmo_fsm_inst *fi);
 
 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 08735fdb..f27359cb 100644
--- a/include/osmocom/core/utils.h
+++ b/include/osmocom/core/utils.h
@@ -140,6 +140,7 @@ bool osmo_is_hexstr(const char *str, int min_digits, int max_digits,
 
 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);