/*      $NetBSD: ping.c,v 1.5 2020/04/30 10:55:32 christos Exp $        */

/*-
* Copyright (c) 2015 The NetBSD Foundation, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in the
*    documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ping.c,v 1.5 2020/04/30 10:55:32 christos Exp $");

#include <sys/param.h>
#include <sys/conf.h>
#include <sys/device.h>
#include <sys/kernel.h>
#include <sys/module.h>

#include "ping.h"

/*
* Create a device /dev/ping in order to test this module.
*
* To use this device you need to do:
*     mknod /dev/ping c 351 0
*
*/

dev_type_open(ping_open);
dev_type_close(ping_close);
dev_type_ioctl(ping_ioctl);

static struct cdevsw ping_cdevsw = {
       .d_open = ping_open,
       .d_close = ping_close,
       .d_read = noread,
       .d_write = nowrite,
       .d_ioctl = ping_ioctl,
       .d_stop = nostop,
       .d_tty = notty,
       .d_poll = nopoll,
       .d_mmap = nommap,
       .d_kqfilter = nokqfilter,
       .d_discard = nodiscard,
       .d_flag = D_OTHER
};


struct ping_softc {
       int             refcnt;
};

static struct ping_softc sc;

int
ping_open(dev_t self __unused, int flag __unused, int mode __unused,
         struct lwp *l __unused)
{
       if (sc.refcnt > 0)
               return EBUSY;

       ++sc.refcnt;

       return 0;
}

int
ping_close(dev_t self __unused, int flag __unused, int mode __unused,
          struct lwp *l __unused)
{
       --sc.refcnt;

       return 0;
}

int
ping_ioctl(dev_t self __unused, u_long cmd, void *data, int flag,
          struct lwp *l __unused)
{
       switch(cmd) {
       case CMD_PING:
               printf("ping: pong!\n");
               return 0;
       default:
               return ENOTTY;
       }
}

MODULE(MODULE_CLASS_MISC, ping, NULL);

static int
ping_modcmd(modcmd_t cmd, void *arg __unused)
{
       /* The major should be verified and changed if needed to avoid
        * conflicts with other devices. */
       int cmajor = 351, bmajor = -1;

       switch (cmd) {
       case MODULE_CMD_INIT:
               if (devsw_attach("ping", NULL, &bmajor, &ping_cdevsw, &cmajor))
                       return ENXIO;
               return 0;
       case MODULE_CMD_FINI:
               if (sc.refcnt > 0)
                       return EBUSY;

               devsw_detach(NULL, &ping_cdevsw);
               return 0;
       default:
               return ENOTTY;
       }
}