presence: Fix database purge of activewatchers (clustering, no fallback2db)

When clustering sharing_tags were added to presence, they were added to
the fallback2db "on" case only:

There are a couple of dimensions with differing behaviours:

                +------------+------------+
                | fallback2- | fallback2- |
                | -db = on   | -db = off  |
  +-clustering:-+------------+------------+
  | - no        | OK         | OK         |
  | - tagless   | PR-2519    | PR-2519    |
  | - active    | OK         | this       |
  +-------------+------------+------------+

The non-OK behaviour above refers to the activewatcher table getting
filled up with stale/expired items.

fallback2db on or off:
  ```
  modparam("presence", "fallback2db", 0)  # or 1=on
  ```

The no-clustering case:
  ```
  handle_subscribe();
  ```

The tagless case:
  ```
  modparam("presence", "cluster_id", 1)
  modparam("clusterer", "my_node_id", 2)

  handle_subscribe();
  ```

The active case:
  ```
  modparam("presence", "cluster_id", 1)
  modparam("clusterer", "my_node_id", 2)
  modparam("clusterer", "sharing_tag", "node2/1=active")

  handle_subscribe("0", "node2");
  ```

Where PR OpenSIPS#2519 fixes the tagless case, this PR fixes the fallback2db=0
case by writing the sharing_tag to the database so the records can get
found and cleaned up.

(Sidenote: subscriptions which ended with a timeout or 481 *would* get
cleaned up. This makes sense in all cases: if they have an error before
their expiry, it makes sense to purge them from the DB immediately. And
it's not a problem if the perioding cleanup had cleaned those records
already.)

Author: wdoekes

modules/presence/subscribe.c

@@ -1364,9 +1364,10 @@ void update_db_subs(db_con_t *db,db_func_t *dbf, shtable_t hash_table,
 	db_op_t update_ops[2];
 	subs_t* del_s;
 	int pres_uri_col, to_user_col, to_domain_col, from_user_col, from_domain_col,
-		callid_col, totag_col, fromtag_col, event_col,status_col, event_id_col,
+		callid_col, totag_col, fromtag_col, event_col, status_col, event_id_col,
 		local_cseq_col, remote_cseq_col, expires_col, record_route_col,
-		contact_col, local_contact_col, version_col,socket_info_col,reason_col;
+		contact_col, local_contact_col, version_col, socket_info_col,
+		sharing_tag_col, reason_col;
 	int u_expires_col, u_local_cseq_col, u_remote_cseq_col, u_version_col,
 		u_reason_col, u_status_col, u_contact_col;
 	int i;
@@ -1472,14 +1473,19 @@ void update_db_subs(db_con_t *db,db_func_t *dbf, shtable_t hash_table,
 		query_vals[local_contact_col].nul = 0;
 		n_query_cols++;
 
+		query_cols[version_col= n_query_cols]=&str_version_col;
+		query_vals[version_col].type = DB_INT;
+		query_vals[version_col].nul = 0;
+		n_query_cols++;
+
 		query_cols[socket_info_col= n_query_cols] =&str_socket_info_col;
 		query_vals[socket_info_col].type = DB_STR;
 		query_vals[socket_info_col].nul = 0;
 		n_query_cols++;
 
-		query_cols[version_col= n_query_cols]=&str_version_col;
-		query_vals[version_col].type = DB_INT;
-		query_vals[version_col].nul = 0;
+		query_cols[sharing_tag_col= n_query_cols] =&str_sharing_tag_col;
+		query_vals[sharing_tag_col].type = DB_STR;
+		query_vals[sharing_tag_col].nul = 0;
 		n_query_cols++;
 
 		/* cols and values used for update */
@@ -1639,10 +1645,16 @@ void update_db_subs(db_con_t *db,db_func_t *dbf, shtable_t hash_table,
 							query_vals[socket_info_col].val.str_val.s = 0;
 							query_vals[socket_info_col].val.str_val.len = 0;
 						}
+						if (s->sh_tag.len == 0) {
+							query_vals[sharing_tag_col].nul = 1;
+						} else {
+							query_vals[sharing_tag_col].nul = 0;
+							query_vals[sharing_tag_col].val.str_val = s->sh_tag;
+						}
 
 						CON_SET_CURR_PS(db, &my_ps_insert);
 						if (dbf->insert( db, query_cols, query_vals,
-						n_query_cols) < 0)
+								n_query_cols) < 0)
 						{
 							LM_ERR("unsuccessful sql insert\n");
 						}