This patch passes output filedescriptor argument (stdout in the
case of SMTP sessions) to the tcp_wrappers code in order to allow
statements like 'twist' (that output anything instead of the daemon)
to work.  Bare hosts_ctl() is too dumb to handle such usage of tcp
wrappers.

--- src/smtp_in.c.orig	2012-06-28 19:52:46.000000000 +0400
+++ src/smtp_in.c	2012-06-28 20:08:00.000000000 +0400
@@ -1357,6 +1357,9 @@
 uschar *user_msg, *log_msg;
 uschar *code, *esc;
 uschar *p, *s, *ss;
+#ifdef USE_TCP_WRAPPERS
+struct request_info tcpwrap_ri;
+#endif
 
 smtp_connection_start = time(NULL);
 for (smtp_ch_index = 0; smtp_ch_index < SMTP_HBUFF_SIZE; smtp_ch_index++)
@@ -1706,10 +1709,14 @@
       "(tcp_wrappers_name) failed: %s", string_printing(tcp_wrappers_name),
         expand_string_message);
     }
-  if (!hosts_ctl(tcp_wrappers_name,
-         (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
-         (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
-         (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident))
+  request_init(&tcpwrap_ri,
+         RQ_DAEMON, tcp_wrappers_name,
+         RQ_FILE, fileno(smtp_out),
+         RQ_CLIENT_NAME, (sender_host_name == NULL)? STRING_UNKNOWN : CS sender_host_name,
+         RQ_CLIENT_ADDR, (sender_host_address == NULL)? STRING_UNKNOWN : CS sender_host_address,
+         RQ_USER, (sender_ident == NULL)? STRING_UNKNOWN : CS sender_ident,
+         0);
+  if (!hosts_access(&tcpwrap_ri))
     {
     if (errno == 0 || errno == ENOENT)
       {