Index: ext/socket/raddrinfo.c
===================================================================
--- ext/socket/raddrinfo.c	(revision 28350)
+++ ext/socket/raddrinfo.c	(working copy)
@@ -270,6 +270,13 @@
         return 0;
     }
     else if (FIXNUM_P(port)) {
+#if defined(__APPLE__)
+/* [ruby-core:29427] it seems Mac OS X cannot accept port "0" */
+	if (FIX2LONG(port) == 0) {
+	    return 0;
+	}
+#endif
+
         snprintf(pbuf, len, "%ld", FIX2LONG(port));
 #ifdef AI_NUMERICSERV
         if (flags_ptr) *flags_ptr |= AI_NUMERICSERV;
@@ -299,9 +306,26 @@
     char hbuf[NI_MAXHOST], pbuf[NI_MAXSERV];
     int additional_flags = 0;
 
+#ifdef __APPLE__
+    if (NIL_P(host) && NIL_P(port)) {
+         rb_raise(rb_eSocket, "At least one of hostname and servname must be non-null.");
+    }
+#endif
+
     hostp = host_str(host, hbuf, sizeof(hbuf), &additional_flags);
     portp = port_str(port, pbuf, sizeof(pbuf), &additional_flags);
 
+#if defined(__APPLE__)
+/* [ruby-core:29427] it seems Mac OS X cannot accept port "0" */
+	if (hostp == NULL && portp == NULL) {
+	    strcpy(pbuf, "0");
+	    portp = pbuf;
+#ifdef AI_NUMERICSERV
+	    additional_flags |= AI_NUMERICSERV;
+#endif
+	}
+#endif
+
     if (socktype_hack && hints->ai_socktype == 0 && str_isnumber(portp)) {
        hints->ai_socktype = SOCK_DGRAM;
     }
Index: test/socket/test_socket.rb
===================================================================
--- test/socket/test_socket.rb	(revision 28350)
+++ test/socket/test_socket.rb	(working copy)
@@ -60,6 +60,12 @@
     assert_raise(SocketError) { Socket.getaddrinfo("www.kame.net", 80, "AF_UNIX") }
   end
 
+  def test_getaddrinfo_raises_no_errors_on_port_argument_of_0
+    assert_nothing_raised("[ruby-core:29427]"){ Socket.getaddrinfo(Socket.gethostname, 0, Socket::AF_INET, Socket::SOCK_STREAM, nil, Socket::AI_CANONNAME) }
+    assert_nothing_raised("[ruby-core:29427]"){ TCPServer.open('localhost', 0) }
+  end
+
+
   def test_getnameinfo
     assert_raise(SocketError) { Socket.getnameinfo(["AF_UNIX", 80, "0.0.0.0"]) }
   end