xref: /freebsd/share/examples/kld/cdev/module/cdevmod.c (revision 7660b554bc59a07be0431c17e0e33815818baa69)
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  * Copyright (c) 1998 Rajesh Vaidheeswarran
8  * All rights reserved.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *      This product includes software developed by Rajesh Vaidheeswarran.
21  * 4. The name Rajesh Vaidheeswarran may not be used to endorse or promote
22  *    products derived from this software without specific prior written
23  *    permission.
24  *
25  * THIS SOFTWARE IS PROVIDED BY RAJESH VAIDHEESWARRAN ``AS IS'' AND ANY
26  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28  * ARE DISCLAIMED.  IN NO EVENT SHALL THE RAJESH VAIDHEESWARRAN BE LIABLE
29  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35  * SUCH DAMAGE.
36  *
37  * Copyright (c) 1993 Terrence R. Lambert.
38  * All rights reserved.
39  *
40  * Redistribution and use in source and binary forms, with or without
41  * modification, are permitted provided that the following conditions
42  * are met:
43  * 1. Redistributions of source code must retain the above copyright
44  *    notice, this list of conditions and the following disclaimer.
45  * 2. Redistributions in binary form must reproduce the above copyright
46  *    notice, this list of conditions and the following disclaimer in the
47  *    documentation and/or other materials provided with the distribution.
48  * 3. All advertising materials mentioning features or use of this software
49  *    must display the following acknowledgement:
50  *      This product includes software developed by Terrence R. Lambert.
51  * 4. The name Terrence R. Lambert may not be used to endorse or promote
52  *    products derived from this software without specific prior written
53  *    permission.
54  *
55  * THIS SOFTWARE IS PROVIDED BY TERRENCE R. LAMBERT ``AS IS'' AND ANY
56  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
57  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
58  * ARE DISCLAIMED.  IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
59  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
60  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
61  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
62  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
63  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
64  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
65  * SUCH DAMAGE.
66  *
67  *
68  * $FreeBSD$
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 #if __FreeBSD_version < 500000
79 #define CDEV_MAJOR 32
80 #else
81 #define CDEV_MAJOR MAJOR_AUTO
82 #endif
83 
84 static struct cdevsw my_devsw = {
85 	/* open */	.d_open = mydev_open,
86 	/* close */	.d_close = mydev_close,
87 	/* read */	.d_read = mydev_read,
88 	/* write */	.d_write = mydev_write,
89 	/* ioctl */	.d_ioctl = mydev_ioctl,
90 	/* name */	.d_name = "cdev",
91 	/* maj */	.d_maj = CDEV_MAJOR
92 };
93 
94 /*
95  * Used as the variable that is the reference to our device
96  * in devfs... we must keep this variable sane until we
97  * call kldunload.
98  */
99 static dev_t sdev;
100 
101 /*
102  * This function is called each time the module is loaded or unloaded.
103  * Since we are a miscellaneous module, we have to provide whatever
104  * code is necessary to patch ourselves into the area we are being
105  * loaded to change.
106  *
107  * The stat information is basically common to all modules, so there
108  * is no real issue involved with stat; we will leave it lkm_nullcmd(),
109  * since we don't have to do anything about it.
110  */
111 
112 static int
113 cdev_load(module_t mod, int cmd, void *arg)
114 {
115     int  err = 0;
116 
117     switch (cmd) {
118     case MOD_LOAD:
119 
120 	/* Do any initialization that you should do with the kernel */
121 
122 	/* if we make it to here, print copyright on console*/
123 	printf("\nSample Loaded kld character device driver\n");
124 	printf("Copyright (c) 1998\n");
125 	printf("Rajesh Vaidheeswarran\n");
126 	printf("All rights reserved\n");
127 	sdev = make_dev(&my_devsw, 0, UID_ROOT, GID_WHEEL, 0600, "cdev");
128 	break;		/* Success*/
129 
130     case MOD_UNLOAD:
131 	printf("Unloaded kld character device driver\n");
132 	destroy_dev(sdev);
133 	break;		/* Success*/
134 
135     default:	/* we only understand load/unload*/
136 	err = EINVAL;
137 	break;
138     }
139 
140     return(err);
141 }
142 
143 /* Now declare the module to the system */
144 
145 DEV_MODULE(cdev, cdev_load, NULL);
146