1/*	$NetBSD: ping.c,v 1.2 2020/02/05 14:10:47 pgoyette Exp $	*/
2
3/*-
4 * Copyright (c) 2020 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__KERNEL_RCSID(0, "$NetBSD: ping.c,v 1.2 2020/02/05 14:10:47 pgoyette Exp $");
31
32#include <sys/param.h>
33#include <sys/conf.h>
34#include <sys/device.h>
35#include <sys/kernel.h>
36#include <sys/module.h>
37
38#include "ping.h"
39
40/*
41 * Create a device /dev/ping in order to test this module.
42 *
43 * To use this device you need to do:
44 *     mknod /dev/ping b 351 0
45 *
46 */
47
48dev_type_open(ping_open);
49dev_type_close(ping_close);
50dev_type_ioctl(ping_ioctl);
51
52static struct cdevsw ping_cdevsw = {
53	.d_open = noopen,
54	.d_close = noclose,
55	.d_read = noread,
56	.d_write = nowrite,
57	.d_ioctl = noioctl,
58	.d_stop = nostop,
59	.d_tty = notty,
60	.d_poll = nopoll,
61	.d_mmap = nommap,
62	.d_kqfilter = nokqfilter,
63	.d_discard = nodiscard,
64	.d_flag = D_OTHER
65};
66
67static struct bdevsw ping_bdevsw = {
68	.d_open = ping_open,
69	.d_close = ping_close,
70	.d_strategy = NULL,
71	.d_ioctl = ping_ioctl,
72	.d_dump = nodump,
73	.d_psize = nosize,
74	.d_discard = nodiscard,
75	.d_flag = D_OTHER
76};
77
78struct ping_softc {
79	int		refcnt;
80};
81
82static struct ping_softc sc;
83
84int
85ping_open(dev_t self __unused, int flag __unused, int mode __unused,
86          struct lwp *l __unused)
87{
88	if (sc.refcnt > 0)
89		return EBUSY;
90
91	++sc.refcnt;
92
93	return 0;
94}
95
96int
97ping_close(dev_t self __unused, int flag __unused, int mode __unused,
98           struct lwp *l __unused)
99{
100	--sc.refcnt;
101
102	return 0;
103}
104
105int
106ping_ioctl(dev_t self __unused, u_long cmd, void *data, int flag,
107           struct lwp *l __unused)
108{
109	switch(cmd) {
110	case CMD_PING:
111		printf("ping: pong!\n");
112		return 0;
113	default:
114		return ENOTTY;
115	}
116}
117
118MODULE(MODULE_CLASS_MISC, ping, NULL);
119
120static int
121ping_modcmd(modcmd_t cmd, void *arg __unused)
122{
123	int bmajor = 351, cmajor = -1;
124
125	switch (cmd) {
126	case MODULE_CMD_INIT:
127		if (devsw_attach("ping", &ping_bdevsw, &bmajor, &ping_cdevsw, &cmajor))
128			return ENXIO;
129		return 0;
130	case MODULE_CMD_FINI:
131		if (sc.refcnt > 0)
132			return EBUSY;
133
134		devsw_detach(&ping_bdevsw, &ping_cdevsw);
135		return 0;
136	default:
137		return ENOTTY;
138	}
139}
140