LXR busybox/console-tools/resize.c

   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 source tree.
   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