source: MondoRescue/branches/3.3/mindi-busybox/console-tools/resize.c@ 3901

/* 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 source tree.
 */
/* no options, no getopt */

//usage:#define resize_trivial_usage
//usage:       ""
//usage:#define resize_full_usage "\n\n"
//usage:       "Resize the screen"

#include "libbb.h"
#include "common_bufsiz.h"

#define ESC "\033"

#define old_termios_p ((struct termios*)bb_common_bufsiz1)
#define INIT_G() do { setup_common_bufsiz(); } while (0)

static void
onintr(int sig UNUSED_PARAM)
{
    tcsetattr(STDERR_FILENO, TCSANOW, old_termios_p);
    _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;

    INIT_G();

    /* 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_p); /* fiddle echo */
    memcpy(&new, old_termios_p, sizeof(new));
    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 */
//BUG: death by signal won't restore termios
    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_p);

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

    return ret;
}