-+ if ((fd = open(file, O_RDWR | O_CREAT, 0700)) < 0) {
-+ fprintf(stderr, "Can't open %s\n", file);
-+ return 1;
++ if ((fd = open(file, O_RDWR | O_CREAT | O_EXCL, 0700)) < 0) {
++ if ((fd = open(file, O_RDWR)) < 0) {
++ fprintf(stderr, "Can't open %s\n", file);
++ return 1;
++ }