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
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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
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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 */
51 main(__unused int argc, __unused char **argv)
53 struct termios old, new;
55 int ret, fd, cnt, error;
57 struct timeval then, now;
61 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1)
65 if (tcgetattr(fd, &old) == -1)
69 new.c_cflag |= (CLOCAL | CREAD);
70 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
71 if (tcsetattr(fd, TCSANOW, &new) == -1)
74 /* Discard input received so far */
75 error = tcflush(fd, TCIOFLUSH);
79 if (write(fd, query, sizeof(query)) != sizeof(query)) {
84 /* Read the response */
85 bzero(data, sizeof(data));
86 gettimeofday(&then, NULL);
89 ret = read(fd, data + cnt, 1);
92 if (errno == EAGAIN) {
93 gettimeofday(&now, NULL);
94 timersub(&now, &then, &now);
95 if (now.tv_sec >= 2) {
96 warnx("timeout reading from terminal");
107 if (data[cnt] == 'R')
111 if (cnt == sizeof(data) - 2) {
112 warnx("response too long");
119 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) {
121 warnx("unable to parse response");
125 /* Finally, what we want */
126 if (ioctl(fd, TIOCSWINSZ, &w) == -1)
130 tcsetattr(fd, TCSANOW, &old);