Add -P <port> option to allow binding to a specific port.

PR:		bin/109494
Submitted by:	mtm
MFC after:	1 week

2 files changed, 61 insertions, 3 deletions

diff --git a/usr.sbin/ypserv/yp_main.c b/usr.sbin/ypserv/yp_main.c
index cfa45e4..7ae15d9 100644
--- a/usr.sbin/ypserv/yp_main.c
+++ b/usr.sbin/ypserv/yp_main.c
@@ -84,6 +84,16 @@ char *yp_dir = _PATH_YP;
 int do_dns = 0;
 int resfd;
 
+struct socktype {
+	const char *st_name;
+	int	   st_type;
+};
+static struct socktype stlist[] = {
+	{ "tcp", SOCK_STREAM },
+	{ "udp", SOCK_DGRAM },
+	{ NULL, 0 }
+};
+
 static
 void _msgout(char* msg)
 {
@@ -187,7 +197,7 @@ reaper(int sig)
 static void
 usage(void)
 {
-	fprintf(stderr, "usage: ypserv [-h] [-d] [-n] [-p path]\n");
+	fprintf(stderr, "usage: ypserv [-h] [-d] [-n] [-p path] [-P port]\n");
 	exit(1);
 }
 
@@ -230,8 +240,11 @@ main(int argc, char *argv[])
 	struct sockaddr_in saddr;
 	socklen_t asize = sizeof (saddr);
 	int ch;
+	in_port_t yp_port = 0;
+	char *errstr;
+	struct socktype *st;
 
-	while ((ch = getopt(argc, argv, "hdnp:")) != -1) {
+	while ((ch = getopt(argc, argv, "hdnp:P:")) != -1) {
 		switch (ch) {
 		case 'd':
 			debug = ypdb_debug = 1;
@@ -242,6 +255,14 @@ main(int argc, char *argv[])
 		case 'p':
 			yp_dir = optarg;
 			break;
+		case 'P':
+			yp_port = (in_port_t)strtonum(optarg, 1, 65535,
+			    (const char **)&errstr);
+			if (yp_port == 0 && errstr != NULL) {
+				_msgout("invalid port number provided");
+				exit(1);
+			}
+			break;
 		case 'h':
 		default:
 			usage();
@@ -277,6 +298,39 @@ main(int argc, char *argv[])
 		(void) pmap_unset(YPPROG, 1);
 	}
 
+	/*
+	 * Initialize TCP/UDP sockets.
+	 */
+	memset((char *)&saddr, 0, sizeof(saddr));
+	saddr.sin_family = AF_INET;
+	saddr.sin_addr.s_addr = htonl(INADDR_ANY);
+	saddr.sin_port = htons(yp_port);
+	for (st = stlist; st->st_name != NULL; st++) {
+		/* Do not bind the socket if the user didn't specify a port */
+		if (yp_port == 0)
+			break;
+
+		sock = socket(AF_INET, st->st_type, 0);
+		if (sock == -1) {
+			if ((asprintf(&errstr, "cannot create a %s socket",
+			    st->st_name)) == -1)
+				err(1, "unexpected failure in asprintf()");
+			_msgout(errstr);
+			free((void *)errstr);
+			exit(1);
+		}
+		if (bind(sock, (struct sockaddr *) &saddr, sizeof(saddr))
+		    == -1) {
+			if ((asprintf(&errstr, "cannot bind %s socket",
+			    st->st_name)) == -1)
+				err(1, "unexpected failure in asprintf()");
+			_msgout(errstr);
+			free((void *)errstr);
+			exit(1);
+		}
+		errstr = NULL;
+	}
+
 	if ((_rpcfdtype == 0) || (_rpcfdtype == SOCK_DGRAM)) {
 		transp = svcudp_create(sock);
 		if (transp == NULL) {
diff --git a/usr.sbin/ypserv/ypserv.8 b/usr.sbin/ypserv/ypserv.8
index 608b202..d4da3b7 100644
--- a/usr.sbin/ypserv/ypserv.8
+++ b/usr.sbin/ypserv/ypserv.8
@@ -30,7 +30,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd February 4, 1995
+.Dd February 3, 2008
 .Dt YPSERV 8
 .Os
 .Sh NAME
@@ -40,6 +40,7 @@
 .Nm
 .Op Fl n
 .Op Fl d
+.Op Fl P Ar port
 .Op Fl p Ar path
 .Sh DESCRIPTION
 .Tn NIS
@@ -403,6 +404,9 @@ in subprocesses, allowing the parent server process to go on handling
 other requests.)
 This makes it easier to trace the server with
 a debugging tool.
+.It Fl P Ar port
+Force ypserv to bind to a specific TCP/UDP port, rather than selecting
+its own.
 .It Fl p Ar path
 Normally,
 .Nm