diff -ur v2/sock_ut.py v3/sock_ut.py
--- v2/sock_ut.py	2021-06-10 21:09:48.000000000 +0900
+++ v3/sock_ut.py	2021-06-24 21:26:04.000000000 +0900
@@ -9,6 +9,8 @@
 import thr
 import dbg
 
+can_read = lambda sc, tmout=0: select.select( [ sc ], [], [], tmout )[ 0 ] == [ sc ]
+
 def port_conn( port, host='localhost' ):
 	cs = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
 	try:
@@ -29,6 +31,15 @@
 	bt = sc.recv( bufmax )
 	return bt
 
+def recv_bt_all( sc ):
+	buf = b''
+	while not buf or can_read( sc ):
+		bt = recv_bt( sc )
+		if not bt:
+			break
+		buf += bt
+	return buf
+
 def send_str( sc, s ):
 	bt = s.encode( 'utf-8' )
 	return send_bt( sc, bt )
@@ -73,11 +84,15 @@
 	q = thr.que_new()
 	srvs[ name ] = q
 
+	dbg.out( 'srv {} start'.format( name ) )
 	while True:
 		s = q.get()
 		if not send_str( sc, s ):
 			break
 
+	srvs.pop( name )
+	dbg.out( 'srv {} quit'.format( name ) )
+
 def base_th_accept( sc, s ):
 	if s not in reqs:
 		return
@@ -131,7 +146,16 @@
 
 	sc.close()
 
+def ping_th( port ):
+	id = 'ping'
+	for ( name, q ) in srvs.items():
+		s = 'port={},srv={},id={}'.format( port, name, id )
+		q.put( s )
+
 def base_srv( port ):
+	th_p = thr.loop_new( ping_th, ( port, ), wait_tmout=1.0 )
+	thr.ths.start( th_p )
+
 	ss = socket.socket( socket.AF_INET, socket.SOCK_STREAM )
 	ss.setsockopt( socket.SOL_SOCKET, socket.SO_REUSEADDR, 1 )
 	ss.bind( ( '', port ) )
@@ -143,6 +167,7 @@
 		th = thr.th_new( base_th, ( port, cs, ev_quit ) )
 		thr.ths.start( th )
 
+	th_p.quit_ev.set()
 	dbg.out( 'base_srv quit' )
 
 def server( port, name ):
@@ -156,7 +181,7 @@
 		return None
 	return ss
 
-def accept( ss ):
+def accept_inner( ss ):
 	s = recv_str( ss )
 	if not s:
 		return None
@@ -165,6 +190,9 @@
 	if not is_accept_dic( d ):
 		return None
 
+	if d.get( 'id' ) == 'ping':
+		return 'ping'
+
 	port = int( d.get( 'port' ) )
 	cs = port_conn( port )
 	if not send_str( cs, s ):
@@ -176,6 +204,15 @@
 		return None
 	return cs
 
+def accept( ss ):
+	cs = None
+	while True:
+		cs = accept_inner( ss )
+		if cs != 'ping':
+			break
+		#dbg.out( 'accept ping' )
+	return cs
+
 def srv_loop( port, name, th_func ):
 	ss = server( port, name )
 	if not ss: