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  */
  10 //config:config DUMPKMAP
  11 //config:       bool "dumpkmap (1.3 kb)"
  12 //config:       default y
  13 //config:       select PLATFORM_LINUX
  14 //config:       help
  15 //config:       This program dumps the kernel's keyboard translation table to
  16 //config:       stdout, in binary format. You can then use loadkmap to load it.
  17
  18 //applet:IF_DUMPKMAP(APPLET_NOEXEC(dumpkmap, dumpkmap, BB_DIR_BIN, BB_SUID_DROP, dumpkmap))
  19 /* bb_common_bufsiz1 usage here is safe wrt NOEXEC: not expecting it to be zeroed. */
  20
  21 //kbuild:lib-$(CONFIG_DUMPKMAP) += dumpkmap.o
  22
  23 //usage:#define dumpkmap_trivial_usage
  24 //usage:       "> keymap"
  25 //usage:#define dumpkmap_full_usage "\n\n"
  26 //usage:       "Print a binary keyboard translation table to stdout"
  27 //usage:
  28 //usage:#define dumpkmap_example_usage
  29 //usage:       "$ dumpkmap > keymap\n"
  30
  31 #include "libbb.h"
  32 #include "common_bufsiz.h"
  33
  34 /* From <linux/kd.h> */
  35 struct kbentry {
  36         unsigned char kb_table;
  37         unsigned char kb_index;
  38         unsigned short kb_value;
  39 };
  40 #define KDGKBENT 0x4B46  /* gets one entry in translation table */
  41
  42 /* From <linux/keyboard.h> */
  43 #define NR_KEYS 128
  44 #define MAX_NR_KEYMAPS 256
  45
  46 int dumpkmap_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  47 int dumpkmap_main(int argc UNUSED_PARAM, char **argv)
  48 {
  49         struct kbentry ke;
  50         int i, j, fd;
  51
  52         /* When user accidentally runs "dumpkmap FILE"
  53          * instead of "dumpkmap >FILE", we'd dump binary stuff to tty.
  54          * Let's prevent it:
  55          */
  56         if (argv[1])
  57                 bb_show_usage();
  58 /*      bb_warn_ignoring_args(argv[1]);*/
  59
  60         fd = get_console_fd_or_die();
  61
  62 #define flags bb_common_bufsiz1
  63         setup_common_bufsiz();
  64         /*                     0 1 2 3 4 5 6 7 8 9 a b c=12 */
  65         memcpy(flags, "bkeymap\1\1\1\0\1\1\1\0\1\1\1\0\1",
  66         /* Can use sizeof, or sizeof-1. sizeof is even, using that */
  67         /****/ sizeof("bkeymap\1\1\1\0\1\1\1\0\1\1\1\0\1")
  68         );
  69         write(STDOUT_FILENO, flags, 7 + MAX_NR_KEYMAPS);
  70 #define flags7 (flags + 7)
  71
  72         for (i = 0; i < 13; i++) {
  73                 if (flags7[i]) {
  74                         for (j = 0; j < NR_KEYS; j++) {
  75                                 ke.kb_index = j;
  76                                 ke.kb_table = i;
  77                                 if (!ioctl_or_perror(fd, KDGKBENT, &ke,
  78                                                 "ioctl(KDGKBENT{%d,%d}) failed",
  79                                                 j, i)
  80                                 ) {
  81                                         write(STDOUT_FILENO, &ke.kb_value, 2);
  82                                 }
  83                         }
  84                 }
  85         }
  86         if (ENABLE_FEATURE_CLEAN_UP) {
  87                 close(fd);
  88         }
  89         return EXIT_SUCCESS;
  90 }