#define _XOPEN_SOURCE 500
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/input.h>

int main(int argc, char **argv)
{
    const char *dev = NULL;
    int fd, freq = 1000, duration = 100000;
    unsigned long snd_bits;
    struct input_event event;

    opterr = 1;
    while (1)
    {
	switch (getopt(argc, argv, "d:f:t:"))
	{
	case 'd':
	    dev = optarg;
	    continue;
	case 'f':
	    freq = strtol(optarg, NULL, 0);
	    continue;
	case 't':
	    duration = strtol(optarg, NULL, 0);
	    continue;
	case -1:
	    break;
	default:
	    continue;;
	}
	break;
    }

    fd = open(dev, O_WRONLY);
    if (fd < 0)
    {
	perror("open");
	return 1;
    }

    if (ioctl(fd, EVIOCGBIT(EV_SND, sizeof snd_bits), &snd_bits) == -1)
    {
	perror("ioctl");
	return 1;
    }

    if (snd_bits & (1 << SND_TONE))
    {
	event.code = SND_TONE;
    }
    else if (snd_bits & (1 << SND_BELL))
    {
	event.code = SND_BELL;
    }
    else
    {
	puts("Neither SND_TONE nor SND_BELL is supported.");
	return 1;
    }

    event.type = EV_SND;
    event.value = freq;
    if (write(fd, &event, sizeof event) < 0)
    {
	perror("write");
    }

    usleep(duration);
    event.value = 0;
    if (write(fd, &event, sizeof event) < 0)
    {
	perror("write");
    }

    return 0;
}