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 //config:config SHOWKEY
  10 //config:       bool "showkey"
  11 //config:       default y
  12 //config:       select PLATFORM_LINUX
  13 //config:       help
  14 //config:         Shows keys pressed.
  15
  16 //applet:IF_SHOWKEY(APPLET(showkey, BB_DIR_USR_BIN, BB_SUID_DROP))
  17
  18 //kbuild:lib-$(CONFIG_SHOWKEY) += showkey.o
  19
  20 //usage:#define showkey_trivial_usage
  21 //usage:       "[-a | -k | -s]"
  22 //usage:#define showkey_full_usage "\n\n"
  23 //usage:       "Show keys pressed\n"
  24 //usage:     "\n        -a      Display decimal/octal/hex values of the keys"
  25 //usage:     "\n        -k      Display interpreted keycodes (default)"
  26 //usage:     "\n        -s      Display raw scan-codes"
  27
  28 #include "libbb.h"
  29 #include <linux/kd.h>
  30
  31
  32 struct globals {
  33         int kbmode;
  34         struct termios tio, tio0;
  35 };
  36 #define G (*ptr_to_globals)
  37 #define kbmode (G.kbmode)
  38 #define tio    (G.tio)
  39 #define tio0   (G.tio0)
  40 #define INIT_G() do { \
  41         SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
  42 } while (0)
  43
  44
  45 // set raw tty mode
  46 // also used by microcom
  47 // libbb candidates?
  48 static void xget1(struct termios *t, struct termios *oldt)
  49 {
  50         tcgetattr(STDIN_FILENO, oldt);
  51         *t = *oldt;
  52         cfmakeraw(t);
  53 }
  54
  55 static void xset1(struct termios *t)
  56 {
  57         int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
  58         if (ret) {
  59                 bb_perror_msg("can't tcsetattr for stdin");
  60         }
  61 }
  62
  63 int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  64 int showkey_main(int argc UNUSED_PARAM, char **argv)
  65 {
  66         enum {
  67                 OPT_a = (1<<0), // display the decimal/octal/hex values of the keys
  68                 OPT_k = (1<<1), // display only the interpreted keycodes (default)
  69                 OPT_s = (1<<2), // display only the raw scan-codes
  70         };
  71
  72         INIT_G();
  73
  74         // FIXME: aks are all mutually exclusive
  75         getopt32(argv, "aks");
  76
  77         // prepare for raw mode
  78         xget1(&tio, &tio0);
  79         // put stdin in raw mode
  80         xset1(&tio);
  81
  82 #define press_keys "Press any keys, program terminates %s:\r\n\n"
  83
  84         if (option_mask32 & OPT_a) {
  85                 // just read stdin char by char
  86                 unsigned char c;
  87
  88                 printf(press_keys, "on EOF (ctrl-D)");
  89
  90                 // read and show byte values
  91                 while (1 == read(STDIN_FILENO, &c, 1)) {
  92                         printf("%3u 0%03o 0x%02x\r\n", c, c, c);
  93                         if (04 /*CTRL-D*/ == c)
  94                                 break;
  95                 }
  96         } else {
  97                 // we assume a PC keyboard
  98                 xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
  99                 printf("Keyboard mode was %s.\r\n\n",
 100                         kbmode == K_RAW ? "RAW" :
 101                                 (kbmode == K_XLATE ? "XLATE" :
 102                                         (kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
 103                                                 (kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
 104                 );
 105
 106                 // set raw keyboard mode
 107                 xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));
 108
 109                 // we should exit on any signal; signals should interrupt read
 110                 bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);
 111
 112                 // inform user that program ends after time of inactivity
 113                 printf(press_keys, "10s after last keypress");
 114
 115                 // read and show scancodes
 116                 while (!bb_got_signal) {
 117                         char buf[18];
 118                         int i, n;
 119
 120                         // setup 10s watchdog
 121                         alarm(10);
 122
 123                         // read scancodes
 124                         n = read(STDIN_FILENO, buf, sizeof(buf));
 125                         i = 0;
 126                         while (i < n) {
 127                                 if (option_mask32 & OPT_s) {
 128                                         // show raw scancodes
 129                                         printf("0x%02x ", buf[i++]);
 130                                 } else {
 131                                         // show interpreted scancodes (default)
 132                                         char c = buf[i];
 133                                         int kc;
 134                                         if (i+2 < n
 135                                          && (c & 0x7f) == 0
 136                                          && (buf[i+1] & 0x80) != 0
 137                                          && (buf[i+2] & 0x80) != 0
 138                                         ) {
 139                                                 kc = ((buf[i+1] & 0x7f) << 7) | (buf[i+2] & 0x7f);
 140                                                 i += 3;
 141                                         } else {
 142                                                 kc = (c & 0x7f);
 143                                                 i++;
 144                                         }
 145                                         printf("keycode %3u %s", kc, (c & 0x80) ? "release" : "press");
 146                                 }
 147                         }
 148                         puts("\r");
 149                 }
 150
 151                 // restore keyboard mode
 152                 xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);
 153         }
 154
 155         // restore console settings
 156         xset1(&tio0);
 157
 158         return EXIT_SUCCESS;
 159 }