xref: /freebsd/share/examples/kld/cdev/module/cdevmod.c (revision a03411e84728e9b267056fd31c7d1d9d1dc1b01e)
1 /* 08 Nov 1998*/
2 /*-
3  * cdevmod.c - a sample kld module implementing a character device driver.
4  *
5  * 08 Nov 1998  Rajesh Vaidheeswarran
6  *
7  * SPDX-License-Identifier: BSD-4-Clause
8  *
9  * Copyright (c) 1998 Rajesh Vaidheeswarran
10  * All rights reserved.
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  * 3. All advertising materials mentioning features or use of this software
21  *    must display the following acknowledgement:
22  *      This product includes software developed by Rajesh Vaidheeswarran.
23  * 4. The name Rajesh Vaidheeswarran may not be used to endorse or promote
24  *    products derived from this software without specific prior written
25  *    permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY RAJESH VAIDHEESWARRAN ``AS IS'' AND ANY
28  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE RAJESH VAIDHEESWARRAN BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  * Copyright (c) 1993 Terrence R. Lambert.
40  * All rights reserved.
41  *
42  * Redistribution and use in source and binary forms, with or without
43  * modification, are permitted provided that the following conditions
44  * are met:
45  * 1. Redistributions of source code must retain the above copyright
46  *    notice, this list of conditions and the following disclaimer.
47  * 2. Redistributions in binary form must reproduce the above copyright
48  *    notice, this list of conditions and the following disclaimer in the
49  *    documentation and/or other materials provided with the distribution.
50  * 3. All advertising materials mentioning features or use of this software
51  *    must display the following acknowledgement:
52  *      This product includes software developed by Terrence R. Lambert.
53  * 4. The name Terrence R. Lambert may not be used to endorse or promote
54  *    products derived from this software without specific prior written
55  *    permission.
56  *
57  * THIS SOFTWARE IS PROVIDED BY TERRENCE R. LAMBERT ``AS IS'' AND ANY
58  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
59  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
60  * ARE DISCLAIMED.  IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
61  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
62  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
63  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
64  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
65  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
66  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
67  * SUCH DAMAGE.
68  *
69  */
70 #include <sys/param.h>
71 #include <sys/systm.h>
72 #include <sys/kernel.h>
73 #include <sys/module.h>
74 #include <sys/conf.h>
75 
76 #include "cdev.h"
77 
78 static struct cdevsw my_devsw = {
79 	/* version */	.d_version = D_VERSION,
80 	/* open */	.d_open = mydev_open,
81 	/* close */	.d_close = mydev_close,
82 	/* read */	.d_read = mydev_read,
83 	/* write */	.d_write = mydev_write,
84 	/* ioctl */	.d_ioctl = mydev_ioctl,
85 	/* name */	.d_name = "cdev"
86 };
87 
88 /*
89  * Used as the variable that is the reference to our device
90  * in devfs... we must keep this variable sane until we
91  * call kldunload.
92  */
93 static struct cdev *sdev;
94 
95 /*
96  * This function is called each time the module is loaded or unloaded.
97  * Since we are a miscellaneous module, we have to provide whatever
98  * code is necessary to patch ourselves into the area we are being
99  * loaded to change.
100  *
101  * The stat information is basically common to all modules, so there
102  * is no real issue involved with stat; we will leave it lkm_nullcmd(),
103  * since we don't have to do anything about it.
104  */
105 
106 static int
107 cdev_load(module_t mod, int cmd, void *arg)
108 {
109     int  err = 0;
110     struct make_dev_args mda;
111 
112     switch (cmd) {
113     case MOD_LOAD:
114 
115 	/* Do any initialization that you should do with the kernel */
116 
117 	/* if we make it to here, print copyright on console*/
118 	printf("\nSample Loaded kld character device driver\n");
119 	printf("Copyright (c) 1998\n");
120 	printf("Rajesh Vaidheeswarran\n");
121 	printf("All rights reserved\n");
122 
123 	make_dev_args_init(&mda);
124 	mda.mda_devsw = &my_devsw;
125 	mda.mda_uid = UID_ROOT;
126 	mda.mda_gid = GID_WHEEL;
127 	mda.mda_mode = 0600;
128 	err = make_dev_s(&mda, &sdev, "cdev");
129 	break;
130 
131     case MOD_UNLOAD:
132 	printf("Unloaded kld character device driver\n");
133 	destroy_dev(sdev);
134 	break;		/* Success*/
135 
136     default:	/* we only understand load/unload*/
137 	err = EOPNOTSUPP;
138 	break;
139     }
140 
141     return(err);
142 }
143 
144 /* Now declare the module to the system */
145 
146 DEV_MODULE(cdev, cdev_load, NULL);
147