--- arcsvc.c~   2005-03-13 16:48:09.000000000 +0100
+++ arcsvc.c    2005-09-17 09:41:51.000000000 +0200
@@ -17,6 +17,9 @@
         Computer Innovations Optimizing C86
 */
 #include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include "arc.h"
 #if    _MTS
 #include <mts.h>
@@ -52,7 +55,12 @@ openarc(chg)                 /* open archive */
        }
 #endif
        if (chg) {              /* if opening for changes */
-               if (!(new = fopen(newname, OPEN_W)))
+               int fd;
+
+               if ((fd = open(newname, O_CREAT|O_EXCL|O_RDWR, S_IREAD|S_IWRITE)) == -1)
+                       arcdie("Cannot create archive copy: %s", newname);
+
+               if (!(new = fdopen(fd, OPEN_W)))
                        arcdie("Cannot create archive copy: %s", newname);
 
        changing = chg;         /* note if open for changes */