Add tcgetwinsize(3) and tcsetwinsize(3) to termios

These functions get/set tty winsize respectively, and are trivial wrappers
around corresponding termio ioctls.

The functions are expected to be a part of POSIX.1 issue 8:
https://www.austingroupbugs.net/view.php?id=1151#c3856.
They are currently available in NetBSD and in musl libc.

PR:	251868
Submitted by:	Soumendra Ganguly <soumendraganguly@gmail.com>
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D27650

include/termios.h

@@ -38,6 +38,9 @@
 #include <sys/cdefs.h>
 #include <sys/_termios.h>
 #include <sys/_types.h>
+#if __BSD_VISIBLE
+#include <sys/_winsize.h>
+#endif
 
 #ifndef _PID_T_DECLARED
 typedef	__pid_t		pid_t;
@@ -92,6 +95,9 @@ int	tcsetsid(int, pid_t);
 void	cfmakeraw(struct termios *);
 void	cfmakesane(struct termios *);
 int	cfsetspeed(struct termios *, speed_t);
+
+int	tcgetwinsize(int, struct winsize *);
+int	tcsetwinsize(int, const struct winsize *);
 #endif
 __END_DECLS
 

lib/libc/gen/Symbol.map

@@ -428,6 +428,8 @@ FBSD_1.6 {
 	sigandset;
 	sigisemptyset;
 	sigorset;
+	tcgetwinsize;
+	tcsetwinsize;
 };
 
 FBSDprivate_1.0 {

lib/libc/gen/termios.c

@@ -275,3 +275,17 @@ tcflow(int fd, int action)
 	}
 	/* NOTREACHED */
 }
+
+int
+tcgetwinsize(int fd, struct winsize *w)
+{
+
+	return (_ioctl(fd, TIOCGWINSZ, w));
+}
+
+int
+tcsetwinsize(int fd, const struct winsize *w)
+{
+
+	return (_ioctl(fd, TIOCSWINSZ, w));
+}

sys/sys/_winsize.h

@@ -0,0 +1,49 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1988, 1989, 1993, 1994
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)ttycom.h	8.1 (Berkeley) 3/28/94
+ * $FreeBSD$
+ */
+
+#ifndef _SYS__WINSIZE_H_
+#define _SYS__WINSIZE_H_
+
+/*
+ * Window/terminal size structure.  This information is stored by the kernel
+ * in order to provide a consistent interface, but is not used by the kernel.
+ */
+struct winsize {
+	unsigned short	ws_row;		/* rows, in characters */
+	unsigned short	ws_col;		/* columns, in characters */
+	unsigned short	ws_xpixel;	/* horizontal size, pixels */
+	unsigned short	ws_ypixel;	/* vertical size, pixels */
+};
+
+#endif /* !_SYS__WINSIZE_H_ */

sys/sys/ttycom.h

@@ -41,23 +41,13 @@
 #define	_SYS_TTYCOM_H_
 
 #include <sys/ioccom.h>
+#include <sys/_winsize.h>
 
 /*
  * Tty ioctl's except for those supported only for backwards compatibility
  * with the old tty driver.
  */
 
-/*
- * Window/terminal size structure.  This information is stored by the kernel
- * in order to provide a consistent interface, but is not used by the kernel.
- */
-struct winsize {
-	unsigned short	ws_row;		/* rows, in characters */
-	unsigned short	ws_col;		/* columns, in characters */
-	unsigned short	ws_xpixel;	/* horizontal size, pixels */
-	unsigned short	ws_ypixel;	/* vertical size, pixels */
-};
-
 						/* 0-2 compat */
 						/* 3-7 unused */
 						/* 8-10 compat */