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	/* 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 ((struct termios)&bb_common_bufsiz1)
15
16	static void
17	onintr(int sig UNUSED_PARAM)
18	{
19	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	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); /* fiddle echo */
37	new = old_termios;
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);
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	}