freebsd-skq/usr.bin/resizewin/resizewin.c
cem f1b3ba4c0d 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
2016-04-13 00:30:42 +00:00

130 lines
3.4 KiB
C

/*
* 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);
}