console-tools/showkey.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * shows keys pressed. inspired by kbd package
   4  *
   5  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   6  *
   7  * Licensed under GPLv2, see file LICENSE in this source tree.
   8  */
   9
  10 //usage:#define showkey_trivial_usage
  11 //usage:       "[-a | -k | -s]"
  12 //usage:#define showkey_full_usage "\n\n"
  13 //usage:       "Show keys pressed\n"
  14 //usage:     "\nOptions:"
  15 //usage:     "\n        -a      Display decimal/octal/hex values of the keys"
  16 //usage:     "\n        -k      Display interpreted keycodes (default)"
  17 //usage:     "\n        -s      Display raw scan-codes"
  18
  19 #include "libbb.h"
  20 #include <linux/kd.h>
  21
  22
  23 struct globals {
  24         int kbmode;
  25         struct termios tio, tio0;
  26 };
  27 #define G (*ptr_to_globals)
  28 #define kbmode (G.kbmode)
  29 #define tio    (G.tio)
  30 #define tio0   (G.tio0)
  31 #define INIT_G() do { \
  32         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  33 } while (0)
  34
  35
  36 // set raw tty mode
  37 // also used by microcom
  38 // libbb candidates?
  39 static void xget1(struct termios *t, struct termios *oldt)
  40 {
  41         tcgetattr(STDIN_FILENO, oldt);
  42         *t = *oldt;
  43         cfmakeraw(t);
  44 }
  45
  46 static void xset1(struct termios *t)
  47 {
  48         int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
  49         if (ret) {
  50                 bb_perror_msg("can't tcsetattr for stdin");
  51         }
  52 }
  53
  54 int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  55 int showkey_main(int argc UNUSED_PARAM, char **argv)
  56 {
  57         enum {
  58                 OPT_a = (1<<0), // display the decimal/octal/hex values of the keys
  59                 OPT_k = (1<<1), // display only the interpreted keycodes (default)
  60                 OPT_s = (1<<2), // display only the raw scan-codes
  61         };
  62
  63         INIT_G();
  64
  65         // FIXME: aks are all mutually exclusive
  66         getopt32(argv, "aks");
  67
  68         // prepare for raw mode
  69         xget1(&tio, &tio0);
  70         // put stdin in raw mode
  71         xset1(&tio);
  72
  73 #define press_keys "Press any keys, program terminates %s:\r\n\n"
  74
  75         if (option_mask32 & OPT_a) {
  76                 // just read stdin char by char
  77                 unsigned char c;
  78
  79                 printf(press_keys, "on EOF (ctrl-D)");
  80
  81                 // read and show byte values
  82                 while (1 == read(STDIN_FILENO, &c, 1)) {
  83                         printf("%3u 0%03o 0x%02x\r\n", c, c, c);
  84                         if (04 /*CTRL-D*/ == c)
  85                                 break;
  86                 }
  87
  88         } else {
  89                 // we assume a PC keyboard
  90                 xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
  91                 printf("Keyboard mode was %s.\r\n\n",
  92                         kbmode == K_RAW ? "RAW" :
  93                                 (kbmode == K_XLATE ? "XLATE" :
  94                                         (kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
  95                                                 (kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
  96                 );
  97
  98                 // set raw keyboard mode
  99                 xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));
 100
 101                 // we should exit on any signal; signals should interrupt read
 102                 bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
 103
 104                 // inform user that program ends after time of inactivity
 105                 printf(press_keys, "10s after last keypress");
 106
 107                 // read and show scancodes
 108                 while (!bb_got_signal) {
 109                         char buf[18];
 110                         int i, n;
 111
 112                         // setup 10s watchdog
 113                         alarm(10);
 114
 115                         // read scancodes
 116                         n = read(STDIN_FILENO, buf, sizeof(buf));
 117                         i = 0;
 118                         while (i < n) {
 119                                 if (option_mask32 & OPT_s) {
 120                                         // show raw scancodes
 121                                         printf("0x%02x ", buf[i++]);
 122                                 } else {
 123                                         // show interpreted scancodes (default)
 124                                         char c = buf[i];
 125                                         int kc;
 126                                         if (i+2 < n
 127                                          && (c & 0x7f) == 0
 128                                          && (buf[i+1] & 0x80) != 0
 129                                          && (buf[i+2] & 0x80) != 0
 130                                         ) {
 131                                                 kc = ((buf[i+1] & 0x7f) << 7) | (buf[i+2] & 0x7f);
 132                                                 i += 3;
 133                                         } else {
 134                                                 kc = (c & 0x7f);
 135                                                 i++;
 136                                         }
 137                                         printf("keycode %3u %s", kc, (c & 0x80) ? "release" : "press");
 138                                 }
 139                         }
 140                         puts("\r");
 141                 }
 142
 143                 // restore keyboard mode
 144                 xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
 145         }
 146
 147         // restore console settings
 148         xset1(&tio0);
 149
 150         return EXIT_SUCCESS;
 151 }