Implemented a "-D" option that causes ftpd to detach and become a daemon -

accepting connections on the FTP port and forking children processes to
handling them. This is lower overhead than spawning ftpd from inetd and
can be a significant win on busy FTP servers. Be sure to disable ftpd in
inetd.conf if you decide to use this option.
These changes are based on similar changes I made to wu-ftpd and have
been in use on wcarchive for several months.

2 files changed, 120 insertions, 29 deletions

diff --git a/libexec/ftpd/ftpd.8 b/libexec/ftpd/ftpd.8
index 6e5b199..8cd6902 100644
--- a/libexec/ftpd/ftpd.8
+++ b/libexec/ftpd/ftpd.8
@@ -41,6 +41,7 @@ Internet File Transfer Protocol server
 .Sh SYNOPSIS
 .Nm ftpd
 .Op Fl dl
+.Op Fl D
 .Op Fl S
 .Op Fl U
 .Op Fl T Ar maxtimeout
@@ -68,6 +69,16 @@ session is logged using syslog with a facility of LOG_FTP.
 If this option is specified twice, the retrieve (get), store (put), append,
 delete, make directory, remove directory and rename operations and
 their filename arguments are also logged.
+.It Fl D
+With this option set,
+.Nm ftpd
+will detach and become a daemon, accepting connections on the FTP port and
+forking children processes to handle them. This is lower overhead than
+starting
+.Nm ftpd
+from
+.Xr inetd 8
+and is thus useful on busy servers to reduce load.
 .It Fl S
 With this option set,
 .Nm ftpd
@@ -295,6 +306,7 @@ Log file for anonymous transfers.
 .Sh SEE ALSO
 .Xr ftp 1 ,
 .Xr getusershell 3 ,
+.Xr inetd 8 ,
 .Xr syslogd 8
 .Sh BUGS
 The server must run as the super-user
diff --git a/libexec/ftpd/ftpd.c b/libexec/ftpd/ftpd.c
index 1137d9f..2d7a041 100644
--- a/libexec/ftpd/ftpd.c
+++ b/libexec/ftpd/ftpd.c
@@ -30,7 +30,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: ftpd.c,v 1.14 1996/01/01 08:35:11 peter Exp $
+ *	$Id: ftpd.c,v 1.15 1996/03/18 11:09:03 davidg Exp $
  */
 
 #ifndef lint
@@ -100,12 +100,14 @@ static char version[] = "Version 6.00";
 extern	off_t restart_point;
 extern	char cbuf[];
 
+struct	sockaddr_in server_addr;
 struct	sockaddr_in ctrl_addr;
 struct	sockaddr_in data_source;
 struct	sockaddr_in data_dest;
 struct	sockaddr_in his_addr;
 struct	sockaddr_in pasv_addr;
 
+int	daemon_mode;
 int	data;
 jmp_buf	errcatch, urgcatch;
 int	logged_in;
@@ -199,6 +201,7 @@ static void	 send_data __P((FILE *, FILE *, off_t, off_t, int));
 static struct passwd *
 		 sgetpwnam __P((char *));
 static char	*sgetsave __P((char *));
+static void	 reapchild __P((int));
 
 static char *
 curdir()
@@ -225,31 +228,6 @@ main(argc, argv, envp)
 
 	tzset();		/* in case no timezone database in ~ftp */
 
-	/*
-	 * LOG_NDELAY sets up the logging connection immediately,
-	 * necessary for anonymous ftp's that chroot and can't do it later.
-	 */
-	openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
-	addrlen = sizeof(his_addr);
-	if (getpeername(0, (struct sockaddr *)&his_addr, &addrlen) < 0) {
-		syslog(LOG_ERR, "getpeername (%s): %m",argv[0]);
-		exit(1);
-	}
-#ifdef SKEY
-	strcpy(addr_string, inet_ntoa(his_addr.sin_addr));
-#endif
-	addrlen = sizeof(ctrl_addr);
-	if (getsockname(0, (struct sockaddr *)&ctrl_addr, &addrlen) < 0) {
-		syslog(LOG_ERR, "getsockname (%s): %m",argv[0]);
-		exit(1);
-	}
-#ifdef IP_TOS
-	tos = IPTOS_LOWDELAY;
-	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(int)) < 0)
-		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
-#endif
-	data_source.sin_port = htons(ntohs(ctrl_addr.sin_port) - 1);
-	debug = 0;
 #ifdef OLD_SETPROCTITLE
 	/*
 	 *  Save start and extent of argv for setproctitle.
@@ -262,11 +240,15 @@ main(argc, argv, envp)
 
 
 #ifdef STATS
-	while ((ch = getopt(argc, argv, "dlSt:T:u:v")) != EOF) {
+	while ((ch = getopt(argc, argv, "dlDSt:T:u:v")) != EOF) {
 #else
-	while ((ch = getopt(argc, argv, "dlUt:T:u:v")) != EOF) {
+	while ((ch = getopt(argc, argv, "dlDUt:T:u:v")) != EOF) {
 #endif
 		switch (ch) {
+		case 'D':
+			daemon_mode++;
+			break;
+
 		case 'd':
 			debug = 1;
 			break;
@@ -316,12 +298,102 @@ main(argc, argv, envp)
 			break;
 		}
 	}
+
 	(void) freopen(_PATH_DEVNULL, "w", stderr);
-	(void) signal(SIGPIPE, lostconn);
+
+	/*
+	 * LOG_NDELAY sets up the logging connection immediately,
+	 * necessary for anonymous ftp's that chroot and can't do it later.
+	 */
+	openlog("ftpd", LOG_PID | LOG_NDELAY, LOG_FTP);
+
+	if (daemon_mode) {
+		int ctl_sock, fd;
+		struct servent *sv;
+
+		/*
+		 * Detach from parent.
+		 */
+		if (daemon(1, 1) < 0) {
+			syslog(LOG_ERR, "failed to become a daemon");
+			exit(1);
+		}
+		(void) signal(SIGCHLD, reapchild);
+		/*
+		 * Get port number for ftp/tcp.
+		 */
+		sv = getservbyname("ftp", "tcp");
+		if (sv == NULL) {
+			syslog(LOG_ERR, "getservbyname for ftp failed");
+			exit(1);
+		}
+		/*
+		 * Open a socket, bind it to the FTP port, and start
+		 * listening.
+		 */
+		ctl_sock = socket(AF_INET, SOCK_STREAM, 0);
+		if (ctl_sock < 0) {
+			syslog(LOG_ERR, "control socket: %m");
+			exit(1);
+		}
+		if (setsockopt(ctl_sock, SOL_SOCKET, SO_REUSEADDR,
+		    (char *)&on, sizeof(on)) < 0)
+			syslog(LOG_ERR, "control setsockopt: %m");;
+		server_addr.sin_family = AF_INET;
+		server_addr.sin_addr.s_addr = INADDR_ANY;
+		server_addr.sin_port = sv->s_port;
+		if (bind(ctl_sock, (struct sockaddr *)&server_addr, sizeof(server_addr))) {
+			syslog(LOG_ERR, "control bind: %m");
+			exit(1);
+		}
+		if (listen(ctl_sock, 32) < 0) {
+			syslog(LOG_ERR, "control listen: %m");
+			exit(1);
+		}
+		/*
+		 * Loop forever accepting connection requests and forking off
+		 * children to handle them.
+		 */
+		while (1) {
+			addrlen = sizeof(his_addr);
+			fd = accept(ctl_sock, (struct sockaddr *)&his_addr, &addrlen);
+			if (fork() == 0) {
+				/* child */
+				(void) dup2(fd, 0);
+				(void) dup2(fd, 1);
+				close(ctl_sock);
+				break;
+			}
+			close(fd);
+		}
+	} else {
+		addrlen = sizeof(his_addr);
+		if (getpeername(0, (struct sockaddr *)&his_addr, &addrlen) < 0) {
+			syslog(LOG_ERR, "getpeername (%s): %m",argv[0]);
+			exit(1);
+		}
+	}
+
 	(void) signal(SIGCHLD, SIG_IGN);
+	(void) signal(SIGPIPE, lostconn);
 	if ((int)signal(SIGURG, myoob) < 0)
 		syslog(LOG_ERR, "signal: %m");
 
+#ifdef SKEY
+	strcpy(addr_string, inet_ntoa(his_addr.sin_addr));
+#endif
+	addrlen = sizeof(ctrl_addr);
+	if (getsockname(0, (struct sockaddr *)&ctrl_addr, &addrlen) < 0) {
+		syslog(LOG_ERR, "getsockname (%s): %m",argv[0]);
+		exit(1);
+	}
+#ifdef IP_TOS
+	tos = IPTOS_LOWDELAY;
+	if (setsockopt(0, IPPROTO_IP, IP_TOS, (char *)&tos, sizeof(int)) < 0)
+		syslog(LOG_WARNING, "setsockopt (IP_TOS): %m");
+#endif
+	data_source.sin_port = htons(ntohs(ctrl_addr.sin_port) - 1);
+
 	/* Try to handle urgent data inline */
 #ifdef SO_OOBINLINE
 	if (setsockopt(0, SOL_SOCKET, SO_OOBINLINE, (char *)&on, sizeof(on)) < 0)
@@ -1781,6 +1853,13 @@ out:
 	}
 }
 
+void
+reapchild(signo)
+	int signo;
+{
+	while (wait3(NULL, WNOHANG, NULL) > 0);
+}
+
 #ifdef OLD_SETPROCTITLE
 /*
  * Clobber argv so ps will show what we're doing.  (Stolen from sendmail.)