4 * Query terminal for size and inform the kernel
6 * Copyright 2015 EMC / Isilon Storage Division
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
32 #include <sys/ioctl.h>
43 /* screen doesn't support ESC[18t (return terminal size) so do it the hard way */
44 static const char query[] =
45 "\0337" /* Save cursor position */
46 "\033[r" /* Scroll whole screen */
47 "\033[999;999H" /* Move cursor */
48 "\033[6n" /* Get cursor position */
49 "\0338"; /* Restore cursor position */
55 fprintf(stderr, "usage: resizewin [-z]\n");
60 main(int argc, char **argv)
62 struct termios old, new;
64 struct timeval then, now;
66 int ch, cnt, error, fd, ret, zflag;
70 while ((ch = getopt(argc, argv, "z")) != -1) {
84 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1)
88 if (ioctl(fd, TIOCGWINSZ, &w) == -1)
90 if (w.ws_row != 0 && w.ws_col != 0)
94 /* Disable echo, flush the input, and drain the output */
95 if (tcgetattr(fd, &old) == -1)
99 new.c_cflag |= (CLOCAL | CREAD);
100 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
101 if (tcsetattr(fd, TCSAFLUSH, &new) == -1)
104 if (write(fd, query, sizeof(query)) != sizeof(query)) {
109 /* Read the response */
110 bzero(data, sizeof(data));
111 gettimeofday(&then, NULL);
114 ret = read(fd, data + cnt, 1);
117 if (errno == EAGAIN) {
118 gettimeofday(&now, NULL);
119 timersub(&now, &then, &now);
120 if (now.tv_sec >= 2) {
121 warnx("timeout reading from terminal");
132 if (data[cnt] == 'R')
136 if (cnt == sizeof(data) - 2) {
137 warnx("response too long");
144 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) {
146 warnx("unable to parse response");
150 /* Finally, what we want */
151 if (ioctl(fd, TIOCSWINSZ, &w) == -1)
155 tcsetattr(fd, TCSANOW, &old);