1/* vi: set sw=4 ts=4: */
2/*
3 * resize - set terminal width and height.
4 *
5 * Copyright 2006 Bernhard Reutner-Fischer
6 *
7 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8 */
9/* no options, no getopt */
10#include "libbb.h"
11
12#define ESC "\033"
13
14#define old_termios_p ((struct termios*)&bb_common_bufsiz1)
15
16static void
17onintr(int sig UNUSED_PARAM)
18{
19	tcsetattr(STDERR_FILENO, TCSANOW, old_termios_p);
20	exit(EXIT_FAILURE);
21}
22
23int resize_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
24int resize_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
25{
26	struct termios new;
27	struct winsize w = { 0, 0, 0, 0 };
28	int ret;
29
30	/* We use _stderr_ in order to make resize usable
31	 * in shell backticks (those redirect stdout away from tty).
32	 * NB: other versions of resize open "/dev/tty"
33	 * and operate on it - should we do the same?
34	 */
35
36	tcgetattr(STDERR_FILENO, old_termios_p); /* fiddle echo */
37	memcpy(&new, old_termios_p, sizeof(new));
38	new.c_cflag |= (CLOCAL | CREAD);
39	new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
40	bb_signals(0
41		+ (1 << SIGINT)
42		+ (1 << SIGQUIT)
43		+ (1 << SIGTERM)
44		+ (1 << SIGALRM)
45		, onintr);
46	tcsetattr(STDERR_FILENO, TCSANOW, &new);
47
48	/* save_cursor_pos 7
49	 * scroll_whole_screen [r
50	 * put_cursor_waaaay_off [$x;$yH
51	 * get_cursor_pos [6n
52	 * restore_cursor_pos 8
53	 */
54	fprintf(stderr, ESC"7" ESC"[r" ESC"[999;999H" ESC"[6n");
55	alarm(3); /* Just in case terminal won't answer */
56	scanf(ESC"[%hu;%huR", &w.ws_row, &w.ws_col);
57	fprintf(stderr, ESC"8");
58
59	/* BTW, other versions of resize recalculate w.ws_xpixel, ws.ws_ypixel
60	 * by calculating character cell HxW from old values
61	 * (gotten via TIOCGWINSZ) and recomputing *pixel values */
62	ret = ioctl(STDERR_FILENO, TIOCSWINSZ, &w);
63
64	tcsetattr(STDERR_FILENO, TCSANOW, old_termios_p);
65
66	if (ENABLE_FEATURE_RESIZE_PRINT)
67		printf("COLUMNS=%d;LINES=%d;export COLUMNS LINES;\n",
68			w.ws_col, w.ws_row);
69
70	return ret;
71}
72