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
This commit is contained in:
cem 2016-04-13 00:30:42 +00:00
parent 47a6833363
commit f1b3ba4c0d
4 changed files with 200 additions and 0 deletions

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@ -125,6 +125,7 @@ SUBDIR= alias \
protect \
rctl \
renice \
resizewin \
rev \
revoke \
rpcinfo \

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@ -0,0 +1,6 @@
# $FreeBSD$
PROG= resizewin
.include <bsd.prog.mk>

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.\" 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.

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/*
* 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);
}