Index: tftpd.c
===================================================================
RCS file: /cvs/src/usr.sbin/tftpd/tftpd.c,v
retrieving revision 1.34
diff -u -p -r1.34 tftpd.c
--- tftpd.c	14 Dec 2015 16:34:55 -0000	1.34
+++ tftpd.c	25 Mar 2016 00:15:05 -0000
@@ -82,6 +82,7 @@
 #include <stdarg.h>
 #include <syslog.h>
 #include <unistd.h>
+#include <paths.h>
 #include <limits.h>
 #include <vis.h>
 
@@ -285,6 +286,7 @@ main(int argc, char *argv[])
 	char *addr = NULL;
 	char *port = "tftp";
 	int family = AF_UNSPEC;
+	int devnull = -1;
 
 	while ((c = getopt(argc, argv, "46cdl:p:r:v")) != -1) {
 		switch (c) {
@@ -337,6 +339,10 @@ main(int argc, char *argv[])
 		openlog(__progname, LOG_PID|LOG_NDELAY, LOG_DAEMON);
 		tzset();
 		logger = &syslogger;
+
+		devnull = open(_PATH_DEVNULL, O_RDWR, 0);
+		if (devnull == -1)
+			err(1, "open %s", _PATH_DEVNULL);
 	}
 
 	if (rewrite != NULL)
@@ -344,9 +350,6 @@ main(int argc, char *argv[])
 
 	tftpd_listen(addr, port, family);
 
-	if (!debug && daemon(1, 0) == -1)
-		err(1, "unable to daemonize");
-
 	if (chroot(dir))
 		err(1, "chroot %s", dir);
 	if (chdir("/"))
@@ -358,8 +361,27 @@ main(int argc, char *argv[])
 	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
 		errx(1, "can't drop privileges");
 
+	if (!debug) {
+		switch (fork()) {
+		case -1:
+			err(1, "fork");
+		case 0:
+			break;
+		default:
+			_exit(0);
+		}
+
+		if (setsid() == -1)
+			err(1, "setsid");
+
+		(void)dup2(devnull, STDIN_FILENO);
+                (void)dup2(devnull, STDOUT_FILENO);
+                (void)dup2(devnull, STDERR_FILENO);
+		(void)close(devnull);
+	}
+
 	if (pledge("stdio rpath wpath cpath fattr dns inet", NULL) == -1)
-		err(1, "pledge");
+		lerr(1, "pledge");
 
 	event_init();