Increase the number of slack file descriptors in connect scan.

CHANGELOG

@@ -1,5 +1,9 @@
 # Nmap Changelog ($Id$); -*-text-*-
 
+o Increased the numberof slack file descriptors not used during connect
+  scan. Previously, the calculation did not consider the descriptors
+  used by various open log files. [David]
+
 o [Zenmap] Fixed internationalization files. Running in a language
   other than the default English would result in the error
   "ValueError: too many values to unpack". [David Fifield]

scan_engine.cc

@@ -942,13 +942,18 @@ void UltraProbe::setConnect(u16 portno) {
 ConnectScanInfo::ConnectScanInfo() {
   maxValidSD = -1;
   numSDs = 0;
-  /* Subtracting 5 from max_sd accounts for
+  /* Subtracting 10 from max_sd accounts for
      stdin
      stdout
      stderr
      /dev/tty
-     /var/run/utmpx, which is opened on Mac OS X at least. */
-  maxSocketsAllowed = (o.max_parallelism) ? o.max_parallelism : MAX(5, max_sd() - 5);
+     /var/run/utmpx, which is opened on Mac OS X at least
+     -oG log file
+     -oN log file
+     -oS log file
+     -oX log file
+     perhaps another we've forgotten. */
+  maxSocketsAllowed = (o.max_parallelism) ? o.max_parallelism : MAX(5, max_sd() - 10);
   FD_ZERO(&fds_read);
   FD_ZERO(&fds_write);
   FD_ZERO(&fds_except);