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