getting client_addr not as a superuser

Hi all,
I have a PG 9.3 and a streaming replication and I need standby ip address in the monitoring. To get that i can run 

select client_addr from pg_stat_replication

but i have to connect as a superuser what's not desirable.

As i see in that view, it uses two functions: pg_stat_get_activity and pg_stat_get_wal_senders and one table pg_authid. As i don't need role information, i've cutted the table from the query and got the following query:
SELECT s.pid, s.client_addr
   FROM pg_stat_get_activity(NULL::integer) s(datid, pid, usesysid, application_name, state, query, waiting, xact_start, query_start, backend_start, state_change, client_addr, client_hostname, client_port)
               ,pg_stat_get_wal_senders() w(pid, state, sent_location, write_location, flush_location, replay_location, sync_priority, sync_state)
 WHERE s.pid = w.pid;
When i run it as a superuser, everything is ok, when i run it as an ordinary user, the client_addr is NULL. As the function pg_stat_get_wal_senders() returns the result, the problem is in receiving the address from pg_stat_get_activity.

Using/granting pg_stat_get_backend_client_addr() is not solving the problem.

Is there any way to get client_addr value running not as a superuser?

Regards, Mikhail