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
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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>
42 /* screen doesn't support ESC[18t (return terminal size) so do it the hard way */
43 static const char query[] =
44 "\0337" /* Save cursor position */
45 "\033[r" /* Scroll whole screen */
46 "\033[999;999H" /* Move cursor */
47 "\033[6n" /* Get cursor position */
48 "\0338"; /* Restore cursor position */
50 main(__unused int argc, __unused char **argv)
52 struct termios old, new;
54 int ret, fd, cnt, err;
56 struct timeval then, now;
60 if ((fd = open("/dev/tty", O_RDWR | O_NONBLOCK)) == -1)
64 if (tcgetattr(fd, &old) == -1)
68 new.c_cflag |= (CLOCAL | CREAD);
69 new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
70 if (tcsetattr(fd, TCSANOW, &new) == -1)
73 if (write(fd, query, sizeof(query)) != sizeof(query)) {
78 /* Read the response */
79 bzero(data, sizeof(data));
80 gettimeofday(&then, NULL);
83 ret = read(fd, data + cnt, 1);
86 if (errno == EAGAIN) {
87 gettimeofday(&now, NULL);
88 timersub(&now, &then, &now);
89 if (now.tv_sec >= 2) {
90 fprintf(stderr, "\n\n\nTimeout reading from terminal\n");
91 fprintf(stderr, "Read %d bytes, %s\n", cnt, data);
102 if (data[cnt] == 'R')
106 if (cnt == sizeof(data) - 2) {
107 fprintf(stderr, "Response too long\n");
114 if (sscanf(data, "\033[%hu;%huR", &w.ws_row, &w.ws_col) != 2) {
116 fprintf(stderr, "Unable to parse response\n");
120 /* Finally, what we want */
121 if (ioctl(fd, TIOCSWINSZ, &w) == -1)
125 tcsetattr(fd, TCSANOW, &old);