Allow getty to execute another program instead of /bin/login

getty.c

@@ -13,7 +13,7 @@
 static void
 usage(void)
 {
-	eprintf("usage: %s [tty] [term]\n", argv0);
+	eprintf("usage: %s [tty] [term] [cmd] [args...]\n", argv0);
 }
 
 static char *tty = "/dev/tty1";
@@ -33,9 +33,6 @@ main(int argc, char *argv[])
 		usage();
 	} ARGEND;
 
-	if (argc > 2)
-		usage();
-
 	strlcpy(term, defaultterm, sizeof(term));
 	if (argc > 0) {
 		tty = argv[0];
@@ -77,6 +74,9 @@ main(int argc, char *argv[])
 	sigemptyset(&sa.sa_mask);
 	sigaction(SIGHUP, &sa, NULL);
 
+	if (argc > 2)
+		return execvp(argv[2], argv + 2);
+
 	printf("Login: ");
 	fflush(stdout);