miscutils/ttysize.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Replacement for "stty size", which is awkward for shell script use.
   4  * - Allows to request width, height, or both, in any order.
   5  * - Does not complain on error, but returns width 80, height 24.
   6  * - Size: less than 200 bytes
   7  *
   8  * Copyright (C) 2007 by Denys Vlasenko <vda.linux@googlemail.com>
   9  *
  10  * Licensed under GPLv2, see file LICENSE in this source tree.
  11  */
  12 //config:config TTYSIZE
  13 //config:       bool "ttysize (718 bytes)"
  14 //config:       default y
  15 //config:       help
  16 //config:       A replacement for "stty size". Unlike stty, can report only width,
  17 //config:       only height, or both, in any order. It also does not complain on
  18 //config:       error, but returns default 80x24.
  19 //config:       Usage in shell scripts: width=`ttysize w`.
  20
  21 //applet:IF_TTYSIZE(APPLET_NOFORK(ttysize, ttysize, BB_DIR_USR_BIN, BB_SUID_DROP, ttysize))
  22
  23 //kbuild:lib-$(CONFIG_TTYSIZE) += ttysize.o
  24
  25 //usage:#define ttysize_trivial_usage
  26 //usage:       "[w] [h]"
  27 //usage:#define ttysize_full_usage "\n\n"
  28 //usage:       "Print dimensions of stdin tty, or 80x24"
  29
  30 #include "libbb.h"
  31
  32 int ttysize_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  33 int ttysize_main(int argc UNUSED_PARAM, char **argv)
  34 {
  35         unsigned w, h;
  36         struct winsize wsz;
  37
  38         w = 80;
  39         h = 24;
  40         if (ioctl(0, TIOCGWINSZ, &wsz) == 0
  41          || ioctl(1, TIOCGWINSZ, &wsz) == 0
  42          || ioctl(2, TIOCGWINSZ, &wsz) == 0
  43         ) {
  44                 w = wsz.ws_col;
  45                 h = wsz.ws_row;
  46         }
  47
  48         if (!argv[1]) {
  49                 printf("%u %u", w, h);
  50         } else {
  51                 const char *fmt, *arg;
  52
  53                 fmt = "%u %u" + 3; /* "%u" */
  54                 while ((arg = *++argv) != NULL) {
  55                         char c = arg[0];
  56                         if (c == 'w')
  57                                 printf(fmt, w);
  58                         if (c == 'h')
  59                                 printf(fmt, h);
  60                         fmt = "%u %u" + 2; /* " %u" */
  61                 }
  62         }
  63         bb_putchar('\n');
  64         return 0;
  65 }