busybox/console-tools/resize.c

/* vi: set sw=4 ts=4: */
/*
 * resize - set terminal width and height.
 *
 * Copyright 2006 Bernhard Reutner-Fischer
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */
/* no options, no getopt */
#include "libbb.h"

#define ESC "\033"

#define old_termios (*(struct termios*)&bb_common_bufsiz1)

static void
onintr(int sig UNUSED_PARAM)
{
	tcsetattr(STDERR_FILENO, TCSANOW, &old_termios);
	exit(EXIT_FAILURE);
}

int resize_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int resize_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
{
	struct termios new;
	struct winsize w = { 0, 0, 0, 0 };
	int ret;

	/* We use _stderr_ in order to make resize usable
	 * in shell backticks (those redirect stdout away from tty).
	 * NB: other versions of resize open "/dev/tty"
	 * and operate on it - should we do the same?
	 */

	tcgetattr(STDERR_FILENO, &old_termios); /* fiddle echo */
	new = old_termios;
	new.c_cflag |= (CLOCAL | CREAD);
	new.c_lflag &= ~(ICANON | ECHO | ECHOE | ISIG);
	bb_signals(0
		+ (1 << SIGINT)
		+ (1 << SIGQUIT)
		+ (1 << SIGTERM)
		+ (1 << SIGALRM)
		, onintr);
	tcsetattr(STDERR_FILENO, TCSANOW, &new);

	/* save_cursor_pos 7
	 * scroll_whole_screen [r
	 * put_cursor_waaaay_off [$x;$yH
	 * get_cursor_pos [6n
	 * restore_cursor_pos 8
	 */
	fprintf(stderr, ESC"7" ESC"[r" ESC"[999;999H" ESC"[6n");
	alarm(3); /* Just in case terminal won't answer */
	scanf(ESC"[%hu;%huR", &w.ws_row, &w.ws_col);
	fprintf(stderr, ESC"8");

	/* BTW, other versions of resize recalculate w.ws_xpixel, ws.ws_ypixel
	 * by calculating character cell HxW from old values
	 * (gotten via TIOCGWINSZ) and recomputing *pixel values */
	ret = ioctl(STDERR_FILENO, TIOCSWINSZ, &w);

	tcsetattr(STDERR_FILENO, TCSANOW, &old_termios);

	if (ENABLE_FEATURE_RESIZE_PRINT)
		printf("COLUMNS=%d;LINES=%d;export COLUMNS LINES;\n",
			w.ws_col, w.ws_row);

	return ret;
}
1	niro	532	/* vi: set sw=4 ts=4: */
2			/*
3			* resize - set terminal width and height.
4			*
5	niro	816	* Copyright 2006 Bernhard Reutner-Fischer
6	niro	532	*
7			* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
8			*/
9			/* no options, no getopt */
10	niro	816	#include "libbb.h"
11	niro	532
12	niro	816	#define ESC "\033"
13
14			#define old_termios ((struct termios)&bb_common_bufsiz1)
15
16			static void
17			onintr(int sig UNUSED_PARAM)
18	niro	532	{
19	niro	816	tcsetattr(STDERR_FILENO, TCSANOW, &old_termios);
20			exit(EXIT_FAILURE);
21			}
22
23			int resize_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
24			int resize_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
25			{
26			struct termios new;
27			struct winsize w = { 0, 0, 0, 0 };
28	niro	532	int ret;
29
30	niro	816	/* 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); /* fiddle echo */
37			new = old_termios;
38	niro	532	new.c_cflag \|= (CLOCAL \| CREAD);
39			new.c_lflag &= ~(ICANON \| ECHO \| ECHOE \| ISIG);
40	niro	816	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	niro	532	/* 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	niro	816	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);
65
66	niro	532	if (ENABLE_FEATURE_RESIZE_PRINT)
67			printf("COLUMNS=%d;LINES=%d;export COLUMNS LINES;\n",
68			w.ws_col, w.ws_row);
69	niro	816
70	niro	532	return ret;
71			}