Fix returned error from gen_tcp:accept/1,2 when running out of ports

The {error, enfile} return value is badly misleading and confusing for
this case, since the Posix ENFILE errno value has a well-defined meaning
that has nothing to do with Erlang ports. The fix changes the return
value to {error, system_limit}, which is consistent with e.g. various
file(3) functions. inet:format_error/1 has also been updated to support
system_limit in the same manner as file:format_error/1.

1 files changed, 1 insertions, 1 deletions

diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 49cd0e5f53..f5a58f9dac 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -743,7 +743,7 @@ driver_create_port(ErlDrvPort creator_port_ix, /* Creating port */
 	return (ErlDrvTermData) -1;   /* pid does not exist */
     }
     if ((port_num = get_free_port()) < 0) {
-	errno = ENFILE;
+	errno = SYSTEM_LIMIT;
 	erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_LINK);
 	erts_smp_mtx_unlock(&erts_driver_list_lock);
 	return (ErlDrvTermData) -1;