1 /*-
2 * Copyright (c) 1999 Assar Westerlund
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * $FreeBSD$
27 */
28
29 #include <sys/param.h>
30 #include <sys/kernel.h>
31 #include <sys/systm.h>
32 #include <sys/malloc.h>
33 #include <sys/sysproto.h>
34 #include <sys/sysent.h>
35 #include <sys/syscall.h>
36 #include <sys/module.h>
37 #include <sys/linker.h>
38 #include <sys/proc.h>
39
40 /*
41 * Acts like "nosys" but can be identified in sysent for dynamic call
42 * number assignment for a limited number of calls.
43 *
44 * Place holder for system call slots reserved for loadable modules.
45 */
46 int
47 lkmnosys(struct proc *p, struct nosys_args *args)
48 {
49 return(nosys(p, args));
50 }
51
52 int
53 syscall_register(int *offset, struct sysent *new_sysent,
54 struct sysent *old_sysent)
55 {
56 if (*offset == NO_SYSCALL) {
57 int i;
58
59 for (i = 1; i < SYS_MAXSYSCALL; ++i)
60 if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
61 break;
62 if (i == SYS_MAXSYSCALL)
63 return ENFILE;
64 *offset = i;
65 } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
66 return EINVAL;
67 else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys)
68 return EEXIST;
69
70 *old_sysent = sysent[*offset];
71 sysent[*offset] = *new_sysent;
72 return 0;
73 }
74
75 int
76 syscall_deregister(int *offset, struct sysent *old_sysent)
77 {
78 if (*offset)
79 sysent[*offset] = *old_sysent;
80 return 0;
81 }
82
83 int
84 syscall_module_handler(struct module *mod, int what, void *arg)
85 {
86 struct syscall_module_data *data = (struct syscall_module_data*)arg;
87 modspecific_t ms;
88 int error;
89
90 switch (what) {
91 case MOD_LOAD :
92 error = syscall_register(data->offset, data->new_sysent,
93 &data->old_sysent);
94 if (error)
95 return error;
96 ms.intval = *data->offset;
97 module_setspecific(mod, &ms);
98 break;
99 case MOD_UNLOAD :
100 error = syscall_deregister(data->offset, &data->old_sysent);
101 if (error)
102 return error;
103 break;
104 }
105 if (data->chainevh)
106 return data->chainevh(mod, what, data->chainarg);
107 else
108 return 0;
109 }
Cache object: 4c0bbacd87c103067e93b4fddfa40ab9
|