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
48 dev_type_open(ping_open);
49 dev_type_close(ping_close);
50 dev_type_ioctl(ping_ioctl);
51
52 static 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
67 static 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
78 struct ping_softc {
79 int refcnt;
80 };
81
82 static struct ping_softc sc;
83
84 int
ping_open(dev_t self __unused,int flag __unused,int mode __unused,struct lwp * l __unused)85 ping_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
96 int
ping_close(dev_t self __unused,int flag __unused,int mode __unused,struct lwp * l __unused)97 ping_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
105 int
ping_ioctl(dev_t self __unused,u_long cmd,void * data,int flag,struct lwp * l __unused)106 ping_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
118 MODULE(MODULE_CLASS_MISC, ping, NULL);
119
120 static int
ping_modcmd(modcmd_t cmd,void * arg __unused)121 ping_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