Index: tcsh/sh.misc.c
===================================================================
--- tcsh.orig/sh.misc.c	2005-01-05 17:06:14.000000000 +0100
+++ tcsh/sh.misc.c	2005-01-09 16:47:41.068433880 +0100
@@ -251,6 +251,7 @@
 closem()
 {
     int f;
+    struct stat st;
 
 #ifdef NLS_BUGS
 #ifdef NLS_CATALOGS
@@ -267,6 +268,16 @@
 #ifdef MALLOC_TRACE
 	    && f != 25
 #endif /* MALLOC_TRACE */
+#ifdef S_ISSOCK
+	    /* NSS modules (e.g. Linux nss_ldap) might keep sockets open.
+	     * If we close such a socket, both the NSS module and tcsh think
+	     * they "own" the descriptor.
+	     *
+	     * Not closing sockets does not make the cleanup use of closem()
+	     * less reliable because tcsh never creates sockets.
+	     */
+	    && fstat(f, &st) == 0 && !S_ISSOCK(st.st_mode)
+#endif
 	    )
 	  {
 	    (void) close(f);