console-tools/dumpkmap.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * Mini dumpkmap implementation for busybox
   4  *
   5  * Copyright (C) Arne Bernin <arne@matrix.loopback.org>
   6  *
   7  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8  */
   9 //config:config DUMPKMAP
  10 //config:       bool "dumpkmap (1.3 kb)"
  11 //config:       default y
  12 //config:       select PLATFORM_LINUX
  13 //config:       help
  14 //config:       This program dumps the kernel's keyboard translation table to
  15 //config:       stdout, in binary format. You can then use loadkmap to load it.
  16
  17 //applet:IF_DUMPKMAP(APPLET_NOEXEC(dumpkmap, dumpkmap, BB_DIR_BIN, BB_SUID_DROP, dumpkmap))
  18 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
  19
  20 //kbuild:lib-$(CONFIG_DUMPKMAP) += dumpkmap.o
  21
  22 //usage:#define dumpkmap_trivial_usage
  23 //usage:       "> keymap"
  24 //usage:#define dumpkmap_full_usage "\n\n"
  25 //usage:       "Print a binary keyboard translation table to stdout"
  26 //usage:
  27 //usage:#define dumpkmap_example_usage
  28 //usage:       "$ dumpkmap > keymap\n"
  29
  30 #include "libbb.h"
  31 #include "common_bufsiz.h"
  32
  33 /* From <linux/kd.h> */
  34 struct kbentry {
  35         unsigned char kb_table;
  36         unsigned char kb_index;
  37         unsigned short kb_value;
  38 };
  39 #define KDGKBENT 0x4B46  /* gets one entry in translation table */
  40
  41 /* From <linux/keyboard.h> */
  42 #define NR_KEYS 128
  43 #define MAX_NR_KEYMAPS 256
  44
  45 int dumpkmap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  46 int dumpkmap_main(int argc UNUSED_PARAM, char **argv)
  47 {
  48         struct kbentry ke;
  49         int i, j, fd;
  50
  51         /* When user accidentally runs "dumpkmap FILE"
  52          * instead of "dumpkmap >FILE", we'd dump binary stuff to tty.
  53          * Let's prevent it:
  54          */
  55         if (argv[1])
  56                 bb_show_usage();
  57 /*      bb_warn_ignoring_args(argv[1]);*/
  58
  59         fd = get_console_fd_or_die();
  60
  61 #define flags bb_common_bufsiz1
  62         setup_common_bufsiz();
  63         /*                     0 1 2 3 4 5 6 7 8 9 a b c=12 */
  64         memcpy(flags, "bkeymap\1\1\1\0\1\1\1\0\1\1\1\0\1",
  65         /* Can use sizeof, or sizeof-1. sizeof is even, using that */
  66         /****/ sizeof("bkeymap\1\1\1\0\1\1\1\0\1\1\1\0\1")
  67         );
  68         write(STDOUT_FILENO, flags, 7 + MAX_NR_KEYMAPS);
  69 #define flags7 (flags + 7)
  70
  71         for (i = 0; i < 13; i++) {
  72                 if (flags7[i]) {
  73                         for (j = 0; j < NR_KEYS; j++) {
  74                                 ke.kb_index = j;
  75                                 ke.kb_table = i;
  76                                 if (!ioctl_or_perror(fd, KDGKBENT, &ke,
  77                                                 "ioctl(KDGKBENT{%d,%d}) failed",
  78                                                 j, i)
  79                                 ) {
  80                                         write(STDOUT_FILENO, &ke.kb_value, 2);
  81                                 }
  82                         }
  83                 }
  84         }
  85         if (ENABLE_FEATURE_CLEAN_UP) {
  86                 close(fd);
  87         }
  88         return EXIT_SUCCESS;
  89 }