This patch is to implement fail safe feature for mailfront plugin clamav.

Giam Teck Choon
http://choon.net/


--- mailfront-1.12/plugin-clamav.c.original	2009-08-06 23:38:08.000000000 +0800
+++ mailfront-1.12/plugin-clamav.c	2009-08-07 00:51:22.000000000 +0800
@@ -48,6 +48,7 @@
   ibuf netin;
   obuf netout;
   struct stat st;
+  const char* clamav_failsafe = session_getenv("CLAMAV_FAILSAFE");
   
   if ((hostname = session_getenv("CLAMAV_HOST")) != 0
       || (hostname = session_getenv("CLAMD_HOST")) != 0) {
@@ -81,8 +82,14 @@
 	|| (send_timeout = strtoul(tmp, (char**)&tmp, 10)) == 0
 	|| *tmp != 0)
       send_timeout = timeout;
-    if ((ip_count = resolve_ipv4name_n(hostname, ips, MAX_IPS)) <= 0)
-      return &resp_no_hostname;
+    if ((ip_count = resolve_ipv4name_n(hostname, ips, MAX_IPS)) <= 0) {
+      if (clamav_failsafe == 0)
+        return &resp_no_hostname;
+      else {
+        warn1("ClamAV scanning skipped: Could not resolve virus scanner hostname");
+        return 0;
+      }
+    }
 
     gettimeofday(&tv, 0);
     offset = (tv.tv_sec ^ tv.tv_usec) % ip_count;
@@ -128,7 +135,12 @@
 	close(sock);
     }
   }
-  return &resp_no_scan;
+  if (clamav_failsafe == 0)
+    return &resp_no_scan;
+  else {
+    warn1("ClamAV scanning skipped: Could not virus scan message");
+    return 0;
+  }
 }
 
 struct plugin plugin = {

--- mailfront-1.12/plugin-clamav.html.original	2009-08-07 00:53:09.000000000 +0800
+++ mailfront-1.12/plugin-clamav.html	2009-08-07 00:58:04.000000000 +0800
@@ -20,6 +20,12 @@
 
 <dl>
 
+<dt><tt>$CLAMAV_FAILSAFE</tt></dt>
+<dd>The default behaviour of the plugin is to defer any SMTP delivery if the
+clamav service is not available including authorized users, at the risk of
+emails being finally rejected if the problem is not fixed. To let any mail
+pass in such a case set this environment variable.</dd>
+
 <dt><tt>$CLAMAV_CONNECT_TIMEOUT</tt></dt> <dd>The maximum amount of time
 to wait for a response when connecting to a ClamAV scanner, in
 milliseconds. (defaults to <tt>$CLAMAV_TIMEOUT</tt> below)</dd>