source: MondoRescue/branches/3.0/mindi-busybox/console-tools/showkey.c

/* vi: set sw=4 ts=4: */
/*
 * shows keys pressed. inspired by kbd package
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

#include "libbb.h"
#include <linux/kd.h>


struct globals {
    int kbmode;
    struct termios tio, tio0;
};
#define G (*ptr_to_globals)
#define kbmode (G.kbmode)
#define tio    (G.tio)
#define tio0   (G.tio0)
#define INIT_G() do { \
    SET_PTR_TO_GLOBALS(xzalloc(sizeof(G))); \
} while (0)


// set raw tty mode
// also used by microcom
// libbb candidates?
static void xget1(struct termios *t, struct termios *oldt)
{
    tcgetattr(STDIN_FILENO, oldt);
    *t = *oldt;
    cfmakeraw(t);
}

static void xset1(struct termios *t)
{
    int ret = tcsetattr(STDIN_FILENO, TCSAFLUSH, t);
    if (ret) {
        bb_perror_msg("can't tcsetattr for stdin");
    }
}

int showkey_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int showkey_main(int argc UNUSED_PARAM, char **argv)
{
    enum {
        OPT_a = (1<<0), // display the decimal/octal/hex values of the keys
        OPT_k = (1<<1), // display only the interpreted keycodes (default)
        OPT_s = (1<<2), // display only the raw scan-codes
    };

    INIT_G();

    // FIXME: aks are all mutually exclusive
    getopt32(argv, "aks");

    // get keyboard settings
    xioctl(STDIN_FILENO, KDGKBMODE, &kbmode);
    printf("kb mode was %s\n\nPress any keys. Program terminates %s\n\n",
        kbmode == K_RAW ? "RAW" :
            (kbmode == K_XLATE ? "XLATE" :
                (kbmode == K_MEDIUMRAW ? "MEDIUMRAW" :
                    (kbmode == K_UNICODE ? "UNICODE" : "UNKNOWN")))
        , (option_mask32 & OPT_a) ? "on EOF (ctrl-D)" : "10s after last keypress"
    );

    // prepare for raw mode
    xget1(&tio, &tio0);
    // put stdin in raw mode
    xset1(&tio);

    if (option_mask32 & OPT_a) {
        unsigned char c;

        // just read stdin char by char
        while (1 == read(STDIN_FILENO, &c, 1)) {
            printf("%3u 0%03o 0x%02x\r\n", c, c, c);
            if (04 /*CTRL-D*/ == c)
                break;
        }
    } else {
        // set raw keyboard mode
        xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)((option_mask32 & OPT_k) ? K_MEDIUMRAW : K_RAW));

        // we should exit on any signal; signals should interrupt read
        bb_signals_recursive_norestart(BB_FATAL_SIGS, record_signo);

        // read and show scancodes
        while (!bb_got_signal) {
            char buf[18];
            int i, n;

            // setup 10s watchdog
            alarm(10);
            // read scancodes
            n = read(STDIN_FILENO, buf, sizeof(buf));
            i = 0;
            while (i < n) {
                if (option_mask32 & OPT_s) {
                    // show raw scancodes
                    printf("0x%02x ", buf[i++]);
                } else {
                    // show interpreted scancodes (default)
                    char c = buf[i];
                    int kc;
                    if (i+2 < n
                     && (c & 0x7f) == 0
                     && (buf[i+1] & 0x80) != 0
                     && (buf[i+2] & 0x80) != 0
                    ) {
                        kc = ((buf[i+1] & 0x7f) << 7) | (buf[i+2] & 0x7f);
                        i += 3;
                    } else {
                        kc = (c & 0x7f);
                        i++;
                    }
                    printf("keycode %3u %s", kc, (c & 0x80) ? "release" : "press");
                }
            }
            puts("\r");
        }
    }

    // restore keyboard and console settings
    xset1(&tio0);
    xioctl(STDIN_FILENO, KDSKBMODE, (void *)(ptrdiff_t)kbmode);

    return EXIT_SUCCESS;
}