lpd: Restore ability to specify a port number

This has been broken since IPv6 support was added in 2000.  We would
validate the port number (which had to be a port number, but can now
also be a service name) and then ignore it.

MFC after:	1 week
Fixes:		08829865f659 ("IPv6 support for lpr.")
Reviewed by:	markj
Differential Revision:	https://reviews.freebsd.org/D57181

2 files changed, 19 insertions, 28 deletions

diff --git a/usr.sbin/lpr/lpd/lpd.8 b/usr.sbin/lpr/lpd/lpd.8
index 9d24a450ba0e..269ef3580ce7 100644
--- a/usr.sbin/lpr/lpd/lpd.8
+++ b/usr.sbin/lpr/lpd/lpd.8
@@ -25,7 +25,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd February 19, 2026
+.Dd May 25, 2026
 .Dt LPD 8
 .Os
 .Sh NAME
@@ -35,7 +35,7 @@
 .Nm
 .Op Fl cdlpsFW46
 .Op Fl t Ar timeout
-.Op Ar port#
+.Op Ar port
 .Sh DEPRECATION NOTICE
 This facility is scheduled for removal prior to the release of
 .Fx 16.0 .
@@ -143,13 +143,13 @@ Inet only.
 Inet6 only.
 .It Fl 46
 Inet and inet6 (default).
-.It Ar "port#"
-The Internet port number used to rendezvous
-with other processes is normally obtained with
-.Xr getservbyname 3
-but can be changed with the
-.Ar port#
-argument.
+.It Ar "port"
+The Internet port number or service name used to rendezvous with other
+processes.
+Can be any number from 1 to 65,535 or any service name defined in
+.Pa /etc/services .
+Defaults to
+.Li printer .
 .El
 .Pp
 Access control is provided by two means.
@@ -346,6 +346,7 @@ but not under same administrative control.
 .Xr syslog 3 ,
 .Xr hosts.lpd 5 ,
 .Xr printcap 5 ,
+.Xr services 5 ,
 .Xr chkprintcap 8 ,
 .Xr lpc 8 ,
 .Xr pac 8
diff --git a/usr.sbin/lpr/lpd/lpd.c b/usr.sbin/lpr/lpd/lpd.c
index d1dcd0766a77..5550846dca18 100644
--- a/usr.sbin/lpr/lpd/lpd.c
+++ b/usr.sbin/lpr/lpd/lpd.c
@@ -101,7 +101,7 @@ static void	 startup(void);
 static void	 chkhost(struct sockaddr *_f, int _ch_opts);
 static int	 ckqueue(struct printer *_pp);
 static void	 fhosterr(int _ch_opts, char *_sysmsg, char *_usermsg);
-static int	*socksetup(int _af, int _debuglvl);
+static int	*socksetup(int _af, const char *portstr, int _debuglvl);
 static void	 usage(void);
 
 /* XXX from libc/net/rcmd.c */
@@ -124,7 +124,7 @@ main(int argc, char **argv)
 	struct sockaddr_storage frominet;
 	socklen_t fromlen;
 	sigset_t omask, nmask;
-	struct servent *sp, serv;
+	const char *portstr = "printer";
 	int inet_flag = 0, inet6_flag = 0;
 
 	euid = geteuid();	/* these shouldn't be different */
@@ -215,19 +215,9 @@ main(int argc, char **argv)
 	if (errs)
 		usage();
 
-	if (argc == 1) {
-		if ((i = atoi(argv[0])) == 0)
-			usage();
-		if (i < 0 || i > USHRT_MAX)
-			errx(EX_USAGE, "port # %d is invalid", i);
-
-		serv.s_port = htons(i);
-		sp = &serv;
+	if (argc > 0) {
+		portstr = *argv++;
 		argc--;
-	} else {
-		sp = getservbyname("printer", "tcp");
-		if (sp == NULL)
-			errx(EX_OSFILE, "printer/tcp: unknown service");
 	}
 
 	if (argc != 0)
@@ -339,7 +329,7 @@ main(int argc, char **argv)
 	FD_SET(funix, &defreadfds);
 	listen(funix, 5);
 	if (sflag == 0) {
-		finet = socksetup(family, socket_debug);
+		finet = socksetup(family, portstr, socket_debug);
 	} else
 		finet = NULL;	/* pretend we couldn't open TCP socket. */
 	if (finet) {
@@ -855,7 +845,7 @@ fhosterr(int ch_opts, char *sysmsg, char *usermsg)
 /* if af is PF_UNSPEC more than one socket may be returned */
 /* the returned list is dynamically allocated, so caller needs to free it */
 static int *
-socksetup(int af, int debuglvl)
+socksetup(int af, const char *portstr, int debuglvl)
 {
 	struct addrinfo hints, *res, *r;
 	int error, maxs, *s, *socks;
@@ -865,7 +855,7 @@ socksetup(int af, int debuglvl)
 	hints.ai_flags = AI_PASSIVE;
 	hints.ai_family = af;
 	hints.ai_socktype = SOCK_STREAM;
-	error = getaddrinfo(NULL, "printer", &hints, &res);
+	error = getaddrinfo(NULL, portstr, &hints, &res);
 	if (error) {
 		syslog(LOG_ERR, "%s", gai_strerror(error));
 		mcleanup(0);
@@ -934,9 +924,9 @@ static void
 usage(void)
 {
 #ifdef INET6
-	fprintf(stderr, "usage: lpd [-cdlsFW46] [port#]\n");
+	fprintf(stderr, "usage: lpd [-cdlsFW46] [port]\n");
 #else
-	fprintf(stderr, "usage: lpd [-cdlsFW] [port#]\n");
+	fprintf(stderr, "usage: lpd [-cdlsFW] [port]\n");
 #endif
 	exit(EX_USAGE);
 }