--- client/clparse.c.orig
+++ client/clparse.c
@@ -210,7 +210,7 @@ int read_client_conf_file (const char *n
 	int token;
 	isc_result_t status;
 	
-	if ((file = open (name, O_RDONLY)) < 0)
+	if ((file = open (name, O_RDONLY | O_CLOEXEC)) < 0)
 		return uerr2isc (errno);
 
 	cfile = NULL;
@@ -247,7 +247,7 @@ void read_client_leases ()
 
 	/* Open the lease file.   If we can't open it, just return -
 	   we can safely trust the server to remember our state. */
-	if ((file = open (path_dhclient_db, O_RDONLY)) < 0)
+	if ((file = open (path_dhclient_db, O_RDONLY | O_CLOEXEC)) < 0)
 		return;
 
 	cfile = NULL;
--- client/dhclient.c.orig
+++ client/dhclient.c
@@ -127,11 +127,11 @@ main(int argc, char **argv) {
 	/* Make sure that file descriptors 0 (stdin), 1, (stdout), and
 	   2 (stderr) are open. To do this, we assume that when we
 	   open a file the lowest available file descriptor is used. */
-	fd = open("/dev/null", O_RDWR);
+	fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 0)
-		fd = open("/dev/null", O_RDWR);
+		fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 1)
-		fd = open("/dev/null", O_RDWR);
+		fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 2)
 		log_perror = 0; /* No sense logging to /dev/null. */
 	else if (fd != -1)
@@ -406,7 +406,7 @@ main(int argc, char **argv) {
 		int e;
 
 		oldpid = 0;
-		if ((pidfd = fopen(path_dhclient_pid, "r")) != NULL) {
+		if ((pidfd = fopen(path_dhclient_pid, "re")) != NULL) {
 			e = fscanf(pidfd, "%ld\n", &temp);
 			oldpid = (pid_t)temp;
 
@@ -2627,7 +2627,7 @@ void rewrite_client_leases ()
 
 	if (leaseFile != NULL)
 		fclose (leaseFile);
-	leaseFile = fopen (path_dhclient_db, "w");
+	leaseFile = fopen (path_dhclient_db, "we");
 	if (leaseFile == NULL) {
 		log_error ("can't create %s: %m", path_dhclient_db);
 		return;
@@ -2731,7 +2731,7 @@ write_duid(struct data_string *duid)
 		return DHCP_R_INVALIDARG;
 
 	if (leaseFile == NULL) {	/* XXX? */
-		leaseFile = fopen(path_dhclient_db, "w");
+		leaseFile = fopen(path_dhclient_db, "we");
 		if (leaseFile == NULL) {
 			log_error("can't create %s: %m", path_dhclient_db);
 			return ISC_R_IOERROR;
@@ -2779,7 +2779,7 @@ write_client6_lease(struct client_state
 		return DHCP_R_INVALIDARG;
 
 	if (leaseFile == NULL) {	/* XXX? */
-		leaseFile = fopen(path_dhclient_db, "w");
+		leaseFile = fopen(path_dhclient_db, "we");
 		if (leaseFile == NULL) {
 			log_error("can't create %s: %m", path_dhclient_db);
 			return ISC_R_IOERROR;
@@ -2911,7 +2911,7 @@ int write_client_lease (client, lease, r
 		return 1;
 
 	if (leaseFile == NULL) {	/* XXX */
-		leaseFile = fopen (path_dhclient_db, "w");
+		leaseFile = fopen (path_dhclient_db, "we");
 		if (leaseFile == NULL) {
 			log_error ("can't create %s: %m", path_dhclient_db);
 			return 0;
@@ -3400,9 +3400,9 @@ void go_daemon ()
 	close(2);
 
 	/* Reopen them on /dev/null. */
-	open("/dev/null", O_RDWR);
-	open("/dev/null", O_RDWR);
-	open("/dev/null", O_RDWR);
+	open("/dev/null", O_RDWR | O_CLOEXEC);
+	open("/dev/null", O_RDWR | O_CLOEXEC);
+	open("/dev/null", O_RDWR | O_CLOEXEC);
 
 	write_client_pid_file ();
 
@@ -3414,14 +3414,14 @@ void write_client_pid_file ()
 	FILE *pf;
 	int pfdesc;
 
-	pfdesc = open (path_dhclient_pid, O_CREAT | O_TRUNC | O_WRONLY, 0644);
+	pfdesc = open (path_dhclient_pid, O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC, 0644);
 
 	if (pfdesc < 0) {
 		log_error ("Can't create %s: %m", path_dhclient_pid);
 		return;
 	}
 
-	pf = fdopen (pfdesc, "w");
+	pf = fdopen (pfdesc, "we");
 	if (!pf)
 		log_error ("Can't fdopen %s: %m", path_dhclient_pid);
 	else {
--- common/bpf.c.orig
+++ common/bpf.c
@@ -94,7 +94,7 @@ int if_register_bpf (info)
 	for (b = 0; 1; b++) {
 		/* %Audit% 31 bytes max. %2004.06.17,Safe% */
 		sprintf(filename, BPF_FORMAT, b);
-		sock = open (filename, O_RDWR, 0);
+		sock = open (filename, O_RDWR | O_CLOEXEC, 0);
 		if (sock < 0) {
 			if (errno == EBUSY) {
 				continue;
--- common/discover.c.orig
+++ common/discover.c
@@ -409,7 +409,7 @@ begin_iface_scan(struct iface_conf_list
 	int len;
 	int i;
 
-	ifaces->fp = fopen("/proc/net/dev", "r");
+	ifaces->fp = fopen("/proc/net/dev", "re");
 	if (ifaces->fp == NULL) {
 		log_error("Error opening '/proc/net/dev' to list interfaces");
 		return 0;
@@ -444,7 +444,7 @@ begin_iface_scan(struct iface_conf_list
 
 #ifdef DHCPv6
 	if (local_family == AF_INET6) {
-		ifaces->fp6 = fopen("/proc/net/if_inet6", "r");
+		ifaces->fp6 = fopen("/proc/net/if_inet6", "re");
 		if (ifaces->fp6 == NULL) {
 			log_error("Error opening '/proc/net/if_inet6' to "
 				  "list IPv6 interfaces; %m");
--- common/dlpi.c.orig
+++ common/dlpi.c
@@ -808,7 +808,7 @@ dlpiopen(const char *ifname) {
 	}
 	*dp = '\0';
 	
-	return open (devname, O_RDWR, 0);
+	return open (devname, O_RDWR | O_CLOEXEC, 0);
 }
 
 /*
--- common/nit.c.orig
+++ common/nit.c
@@ -81,7 +81,7 @@ int if_register_nit (info)
 	struct strioctl sio;
 
 	/* Open a NIT device */
-	sock = open ("/dev/nit", O_RDWR);
+	sock = open ("/dev/nit", O_RDWR | O_CLOEXEC);
 	if (sock < 0)
 		log_fatal ("Can't open NIT device for %s: %m", info -> name);
 
--- common/resolv.c.orig
+++ common/resolv.c
@@ -49,7 +49,7 @@ void read_resolv_conf (parse_time)
 	struct domain_search_list *dp, *dl, *nd;
 	isc_result_t status;
 
-	if ((file = open (path_resolv_conf, O_RDONLY)) < 0) {
+	if ((file = open (path_resolv_conf, O_RDONLY | O_CLOEXEC)) < 0) {
 		log_error ("Can't open %s: %m", path_resolv_conf);
 		return;
 	}
--- common/upf.c.orig
+++ common/upf.c
@@ -77,7 +77,7 @@ int if_register_upf (info)
 		/* %Audit% Cannot exceed 36 bytes. %2004.06.17,Safe% */
 		sprintf(filename, "/dev/pf/pfilt%d", b);
 
-		sock = open (filename, O_RDWR, 0);
+		sock = open (filename, O_RDWR | O_CLOEXEC, 0);
 		if (sock < 0) {
 			if (errno == EBUSY) {
 				continue;
--- dst/dst_api.c.orig
+++ dst/dst_api.c
@@ -437,7 +437,7 @@ dst_s_write_private_key(const DST_KEY *k
 			     PRIVATE_KEY, PATH_MAX);
 
 	/* Do not overwrite an existing file */
-	if ((fp = dst_s_fopen(file, "w", 0600)) != NULL) {
+	if ((fp = dst_s_fopen(file, "we", 0600)) != NULL) {
 		int nn;
 		if ((nn = fwrite(encoded_block, 1, len, fp)) != len) {
 			EREPORT(("dst_write_private_key(): Write failure on %s %d != %d errno=%d\n",
@@ -494,7 +494,7 @@ dst_s_read_public_key(const char *in_nam
 	 * flags, proto, alg stored as decimal (or hex numbers FIXME).
 	 * (FIXME: handle parentheses for line continuation.)
 	 */
-	if ((fp = dst_s_fopen(name, "r", 0)) == NULL) {
+	if ((fp = dst_s_fopen(name, "re", 0)) == NULL) {
 		EREPORT(("dst_read_public_key(): Public Key not found %s\n",
 			 name));
 		return (NULL);
@@ -620,7 +620,7 @@ dst_s_write_public_key(const DST_KEY *ke
 		return (0);
 	}
 	/* create public key file */
-	if ((fp = dst_s_fopen(filename, "w+", 0644)) == NULL) {
+	if ((fp = dst_s_fopen(filename, "w+e", 0644)) == NULL) {
 		EREPORT(("DST_write_public_key: open of file:%s failed (errno=%d)\n",
 			 filename, errno));
 		return (0);
@@ -854,7 +854,7 @@ dst_s_read_private_key_file(char *name,
 		return (0);
 	}
 	/* first check if we can find the key file */
-	if ((fp = dst_s_fopen(filename, "r", 0)) == NULL) {
+	if ((fp = dst_s_fopen(filename, "re", 0)) == NULL) {
 		EREPORT(("dst_s_read_private_key_file: Could not open file %s in directory %s\n",
 			 filename, dst_path[0] ? dst_path :
 			 (char *) getcwd(NULL, PATH_MAX - 1)));
--- dst/prandom.c.orig
+++ dst/prandom.c
@@ -269,7 +269,7 @@ get_dev_random(u_char *output, unsigned
 
 	s = stat("/dev/random", &st);
 	if (s == 0 && S_ISCHR(st.st_mode)) {
-		if ((fd = open("/dev/random", O_RDONLY | O_NONBLOCK)) != -1) {
+		if ((fd = open("/dev/random", O_RDONLY | O_NONBLOCK | O_CLOEXEC)) != -1) {
 			if ((n = read(fd, output, size)) < 0)
 				n = 0;
 			close(fd);
@@ -480,7 +480,7 @@ digest_file(dst_work *work)
 		work->file_digest = dst_free_key(work->file_digest);
 		return (0);
 	}
-	if ((fp = fopen(name, "r")) == NULL) 
+	if ((fp = fopen(name, "re")) == NULL) 
 		return (0);
 	for (no = 0; (i = fread(buf, sizeof(*buf), sizeof(buf), fp)) > 0; 
 	     no += i) 
--- omapip/trace.c.orig
+++ omapip/trace.c
@@ -141,10 +141,10 @@ isc_result_t trace_begin (const char *fi
 		return DHCP_R_INVALIDARG;
 	}
 
-	traceoutfile = open (filename, O_CREAT | O_WRONLY | O_EXCL, 0600);
+	traceoutfile = open (filename, O_CREAT | O_WRONLY | O_EXCL | O_CLOEXEC, 0600);
 	if (traceoutfile < 0 && errno == EEXIST) {
 		log_error ("WARNING: Overwriting trace file \"%s\"", filename);
-		traceoutfile = open (filename, O_WRONLY | O_EXCL | O_TRUNC,
+		traceoutfile = open (filename, O_WRONLY | O_EXCL | O_TRUNC | O_CLOEXEC,
 				     0600);
 	}
 
@@ -431,7 +431,7 @@ void trace_file_replay (const char *file
 	isc_result_t result;
 	int len;
 
-	traceinfile = fopen (filename, "r");
+	traceinfile = fopen (filename, "re");
 	if (!traceinfile) {
 		log_error("Can't open tracefile %s: %m", filename);
 		return;
--- relay/dhcrelay.c.orig
+++ relay/dhcrelay.c
@@ -177,11 +177,11 @@ main(int argc, char **argv) {
 	/* Make sure that file descriptors 0(stdin), 1,(stdout), and
 	   2(stderr) are open. To do this, we assume that when we
 	   open a file the lowest available file descriptor is used. */
-	fd = open("/dev/null", O_RDWR);
+	fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 0)
-		fd = open("/dev/null", O_RDWR);
+		fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 1)
-		fd = open("/dev/null", O_RDWR);
+		fd = open("/dev/null", O_RDWR | O_CLOEXEC);
 	if (fd == 2)
 		log_perror = 0; /* No sense logging to /dev/null. */
 	else if (fd != -1)
@@ -520,12 +520,12 @@ main(int argc, char **argv) {
 			exit(0);
 
 		pfdesc = open(path_dhcrelay_pid,
-			       O_CREAT | O_TRUNC | O_WRONLY, 0644);
+			       O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC, 0644);
 
 		if (pfdesc < 0) {
 			log_error("Can't create %s: %m", path_dhcrelay_pid);
 		} else {
-			pf = fdopen(pfdesc, "w");
+			pf = fdopen(pfdesc, "we");
 			if (!pf)
 				log_error("Can't fdopen %s: %m",
 				      path_dhcrelay_pid);
--- server/confpars.c.orig
+++ server/confpars.c
@@ -116,7 +116,7 @@ isc_result_t read_conf_file (const char
 	}
 #endif
 
-	if ((file = open (filename, O_RDONLY)) < 0) {
+	if ((file = open (filename, O_RDONLY | O_CLOEXEC)) < 0) {
 		if (leasep) {
 			log_error ("Can't open lease database %s: %m --",
 				   path_dhcpd_db);
--- server/db.c.orig
+++ server/db.c
@@ -1035,7 +1035,7 @@ void db_startup (testp)
 	}
 #endif
 	if (!testp) {
-		db_file = fopen (path_dhcpd_db, "a");
+		db_file = fopen (path_dhcpd_db, "ae");
 		if (!db_file)
 			log_fatal ("Can't open %s for append.", path_dhcpd_db);
 		expire_all_pools ();
@@ -1074,7 +1074,7 @@ int new_lease_file ()
 	db_validity = lease_file_is_corrupt;
 
 	snprintf (newfname, sizeof(newfname), "%s.XXXXXX", path_dhcpd_db);
-	db_fd = mkstemp (newfname);
+	db_fd = mkostemp (newfname, O_CLOEXEC);
 	if (db_fd < 0) {
 		log_error ("Can't create new lease file: %m");
 		return 0;
@@ -1083,7 +1083,7 @@ int new_lease_file ()
 		log_error ("Can't fchmod new lease file: %m");
 		goto fail;
 	}
-	if ((new_db_file = fdopen(db_fd, "w")) == NULL) {
+	if ((new_db_file = fdopen(db_fd, "we")) == NULL) {
 		log_error("Can't fdopen new lease file: %m");
 		close(db_fd);
 		goto fdfail;
--- server/dhcpd.c.orig
+++ server/dhcpd.c
@@ -272,11 +272,11 @@ main(int argc, char **argv) {
         /* Make sure that file descriptors 0 (stdin), 1, (stdout), and
            2 (stderr) are open. To do this, we assume that when we
            open a file the lowest available file descriptor is used. */
-        fd = open("/dev/null", O_RDWR);
+        fd = open("/dev/null", O_RDWR | O_CLOEXEC);
         if (fd == 0)
-                fd = open("/dev/null", O_RDWR);
+                fd = open("/dev/null", O_RDWR | O_CLOEXEC);
         if (fd == 1)
-                fd = open("/dev/null", O_RDWR);
+                fd = open("/dev/null", O_RDWR | O_CLOEXEC);
         if (fd == 2)
                 log_perror = 0; /* No sense logging to /dev/null. */
         else if (fd != -1)
@@ -800,7 +800,7 @@ main(int argc, char **argv) {
 #endif /* PARANOIA */
 
 	/* Read previous pid file. */
-	if ((i = open (path_dhcpd_pid, O_RDONLY)) >= 0) {
+	if ((i = open (path_dhcpd_pid, O_RDONLY | O_CLOEXEC)) >= 0) {
 		status = read(i, pbuf, (sizeof pbuf) - 1);
 		close (i);
 		if (status > 0) {
@@ -818,7 +818,7 @@ main(int argc, char **argv) {
 	}
 
         /* Write new pid file. */
-        if ((i = open(path_dhcpd_pid, O_WRONLY|O_CREAT|O_TRUNC, 0644)) >= 0) {
+        if ((i = open(path_dhcpd_pid, O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0644)) >= 0) {
                 sprintf(pbuf, "%d\n", (int) getpid());
                 IGNORE_RET (write(i, pbuf, strlen(pbuf)));
                 close(i);
@@ -844,9 +844,9 @@ main(int argc, char **argv) {
                 close(2);
 
                 /* Reopen them on /dev/null. */
-                open("/dev/null", O_RDWR);
-                open("/dev/null", O_RDWR);
-                open("/dev/null", O_RDWR);
+                open("/dev/null", O_RDWR | O_CLOEXEC);
+                open("/dev/null", O_RDWR | O_CLOEXEC);
+                open("/dev/null", O_RDWR | O_CLOEXEC);
                 log_perror = 0; /* No sense logging to /dev/null. */
 
        		IGNORE_RET (chdir("/"));
--- server/ldap.c.orig
+++ server/ldap.c
@@ -1098,7 +1098,7 @@ ldap_start (void)
 
   if (ldap_debug_file != NULL && ldap_debug_fd == -1)
     {
-      if ((ldap_debug_fd = open (ldap_debug_file, O_CREAT | O_TRUNC | O_WRONLY,
+      if ((ldap_debug_fd = open (ldap_debug_file, O_CREAT | O_TRUNC | O_WRONLY | O_CLOEXEC,
                                  S_IRUSR | S_IWUSR)) < 0)
         log_error ("Error opening debug LDAP log file %s: %s", ldap_debug_file,
                    strerror (errno));