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