1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
|
/*-
* Copyright (c) 1999 Assar Westerlund
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/syscall.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sx.h>
#include <sys/module.h>
/*
* Acts like "nosys" but can be identified in sysent for dynamic call
* number assignment for a limited number of calls.
*
* Place holder for system call slots reserved for loadable modules.
*/
int
lkmnosys(struct thread *td, struct nosys_args *args)
{
return(nosys(td, args));
}
int
lkmressys(struct thread *td, struct nosys_args *args)
{
return(nosys(td, args));
}
int
syscall_register(int *offset, struct sysent *new_sysent,
struct sysent *old_sysent)
{
if (*offset == NO_SYSCALL) {
int i;
for (i = 1; i < SYS_MAXSYSCALL; ++i)
if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
break;
if (i == SYS_MAXSYSCALL)
return ENFILE;
*offset = i;
} else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
return EINVAL;
else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys &&
sysent[*offset].sy_call != (sy_call_t *)lkmressys)
return EEXIST;
*old_sysent = sysent[*offset];
sysent[*offset] = *new_sysent;
return 0;
}
int
syscall_deregister(int *offset, struct sysent *old_sysent)
{
if (*offset)
sysent[*offset] = *old_sysent;
return 0;
}
int
syscall_module_handler(struct module *mod, int what, void *arg)
{
struct syscall_module_data *data = (struct syscall_module_data*)arg;
modspecific_t ms;
int error;
switch (what) {
case MOD_LOAD :
error = syscall_register(data->offset, data->new_sysent,
&data->old_sysent);
if (error) {
/* Leave a mark so we know to safely unload below. */
data->offset = NULL;
return error;
}
ms.intval = *data->offset;
MOD_XLOCK;
module_setspecific(mod, &ms);
MOD_XUNLOCK;
if (data->chainevh)
error = data->chainevh(mod, what, data->chainarg);
return error;
case MOD_UNLOAD :
/*
* MOD_LOAD failed, so just return without calling the
* chained handler since we didn't pass along the MOD_LOAD
* event.
*/
if (data->offset == NULL)
return (0);
if (data->chainevh) {
error = data->chainevh(mod, what, data->chainarg);
if (error)
return error;
}
error = syscall_deregister(data->offset, &data->old_sysent);
return error;
default :
return EOPNOTSUPP;
}
if (data->chainevh)
return data->chainevh(mod, what, data->chainarg);
else
return 0;
}
|
