Add a small tool, resizewin(1), to query terminal for window size

Submitted by:	Daniel O'Connor
Reviewed by:	kan, wblock, cem
Sponsored by:	EMC / Isilon Storage Division
Differential Revision:	https://reviews.freebsd.org/D4438

3 files changed, 199 insertions, 0 deletions

diff --git a/usr.bin/resizewin/Makefile b/usr.bin/resizewin/Makefile
new file mode 100644
index 000000000000..013109b4ecbe
--- /dev/null
+++ b/usr.bin/resizewin/Makefile
@@ -0,0 +1,6 @@
+# $FreeBSD$
+
+PROG=		resizewin
+
+.include <bsd.prog.mk>
+
diff --git a/usr.bin/resizewin/resizewin.1 b/usr.bin/resizewin/resizewin.1
new file mode 100644
index 000000000000..85dd829e53dd
--- /dev/null
+++ b/usr.bin/resizewin/resizewin.1
@@ -0,0 +1,64 @@
+.\" resizewin
+.\"
+.\" Query terminal for size and inform the kernel
+.\"
+.\" Copyright 2015 EMC / Isilon Storage Division
+.\"
+.\" 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.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+
+.\" $FreeBSD$
+.\"
+.Dd March 17, 2016
+.Dt RESIZEWIN 1
+.Os
+.Sh NAME
+.Nm resizewin
+.Nd update the kernel window size for the current TTY
+.Sh DESCRIPTION
+Query the terminal emulator window size with the
+.Dv TIOCSWINSZ
+ioctl and set the window size known by the kernel to the new values.
+The terminal is assumed to be VT100/ANSI compatible.
+.Nm
+is functionally similar to
+.Xr resize 1 ,
+which is part of the
+.Xr xterm 1
+distribution.
+However,
+.Nm
+only works with VT100/ANSI-compatible terminals and does
+not emit commands to set environment variables.
+.Pp
+After a terminal window has been resized, running
+.Nm
+updates the kernel's window size to match the new size.
+.Pp
+Note that virtually all modern terninals support VT100/ANSI escape
+sequences, including xterm, konsole, gnome-terminal iTerm,
+Terminal.app, and puTTY.
+.Sh SEE ALSO
+.Xr resize 1 ,
+.Xr stty 1
+.Sh HISTORY
+.Nm
+appeared in FreeBSD 11.
diff --git a/usr.bin/resizewin/resizewin.c b/usr.bin/resizewin/resizewin.c
new file mode 100644
index 000000000000..5399ad33a0e4
--- /dev/null
+++ b/usr.bin/resizewin/resizewin.c
@@ -0,0 +1,129 @@
+/*
+ * resizewin
+ *
+ * Query terminal for size and inform the kernel
+ *
+ * Copyright 2015 EMC / Isilon Storage Division
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+#include <sys/ioctl.h>
+#include <sys/time.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <strings.h>
+#include <termios.h>
+#include <unistd.h>
+
+/* screen doesn't support ESC[18t (return terminal size) so do it the hard way */
+static const char query[] =
+    "\0337"		/* Save cursor position */
+    "\033[r"		/* Scroll whole screen */
+    "\033[999;999H"	/* Move cursor */
+    "\033[6n"		/* Get cursor position */
+    "\0338";		/* Restore cursor position */
+int
+main(__unused int argc, __unused char **argv)
+{
+	struct termios old, new;
+	struct winsize w;
+	int ret, fd, cnt, err;
+	char data[20];
+	struct timeval then, now;
+
+	err = 0;
+
+	if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1)
+		exit(1);
+
+	/* Disable echo */
+	if (tcgetattr(fd, &old) == -1)
+		exit(1);
+
+	new = old;
+	new.c_cflag |= (CLOCAL | CREAD);
+	new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
+	if (tcsetattr(fd, TCSANOW, &new) == -1)
+		exit(1);
+
+	if (write(fd, query, sizeof(query)) != sizeof(query)) {
+		err = 1;
+		goto out;
+	}
+
+	/* Read the response */
+	bzero(data, sizeof(data));
+	gettimeofday(&then, NULL);
+	cnt = 0;
+	while (1) {
+		ret = read(fd, data + cnt, 1);
+
+		if (ret == -1) {
+			if (errno == EAGAIN) {
+				gettimeofday(&now, NULL);
+				timersub(&now, &then, &now);
+				if (now.tv_sec >= 2) {
+					fprintf(stderr, "\n\n\nTimeout reading from terminal\n");
+					fprintf(stderr, "Read %d bytes, %s\n", cnt, data);
+					err = 1;
+					goto out;
+				}
+
+				usleep(20000);
+				continue;
+			}
+			err = 1;
+			goto out;
+		}
+		if (data[cnt] == 'R')
+			break;
+
+		cnt++;
+		if (cnt == sizeof(data) - 2) {
+			fprintf(stderr, "Response too long\n");
+			err = 1;
+			goto out;
+		}
+	}
+
+	/* Parse */
+	if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) {
+		err = 1;
+		fprintf(stderr, "Unable to parse response\n");
+		goto out;
+	}
+
+	/* Finally, what we want */
+	if (ioctl(fd, TIOCSWINSZ, &w) == -1)
+		err = 1;
+ out:
+	/* Restore echo */
+	tcsetattr(fd, TCSANOW, &old);
+
+	close(fd);
+	exit(err);
+}