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