1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 1999 Assar Westerlund
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 AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <sys/param.h>
32 #include <sys/proc.h>
33 #include <sys/module.h>
34 #include <sys/sysproto.h>
35 #include <sys/sysent.h>
36 #include <sys/kernel.h>
37 #include <sys/systm.h>
38 
39 /*
40  * The function for implementing the syscall.
41  */
42 static int
43 hello(struct thread *td, void *arg)
44 {
45 
46 	printf("hello kernel\n");
47 	return (0);
48 }
49 
50 /*
51  * The `sysent' for the new syscall
52  */
53 static struct sysent hello_sysent = {
54 	.sy_narg = 0,
55 	.sy_call = hello
56 };
57 
58 /*
59  * The offset in sysent where the syscall is allocated.
60  */
61 static int offset = NO_SYSCALL;
62 
63 /*
64  * The function called at load/unload.
65  */
66 static int
67 load(struct module *module, int cmd, void *arg)
68 {
69 	int error = 0;
70 
71 	switch (cmd) {
72 	case MOD_LOAD :
73 		printf("syscall loaded at %d\n", offset);
74 		break;
75 	case MOD_UNLOAD :
76 		printf("syscall unloaded from %d\n", offset);
77 		break;
78 	default :
79 		error = EOPNOTSUPP;
80 		break;
81 	}
82 	return (error);
83 }
84 
85 SYSCALL_MODULE(syscall, &offset, &hello_sysent, load, NULL);
86