2 * Copyright (c) 1999 Assar Westerlund
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
30 #include <sys/param.h>
32 #include <sys/module.h>
34 #include <sys/syscall.h>
35 #include <sys/sysent.h>
36 #include <sys/sysproto.h>
39 * Acts like "nosys" but can be identified in sysent for dynamic call
40 * number assignment for a limited number of calls.
42 * Place holder for system call slots reserved for loadable modules.
45 lkmnosys(struct thread *td, struct nosys_args *args)
48 return (nosys(td, args));
52 lkmressys(struct thread *td, struct nosys_args *args)
55 return (nosys(td, args));
59 syscall_register(int *offset, struct sysent *new_sysent,
60 struct sysent *old_sysent)
64 if (*offset == NO_SYSCALL) {
65 for (i = 1; i < SYS_MAXSYSCALL; ++i)
66 if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
68 if (i == SYS_MAXSYSCALL)
71 } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
73 else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys &&
74 sysent[*offset].sy_call != (sy_call_t *)lkmressys)
77 *old_sysent = sysent[*offset];
78 sysent[*offset] = *new_sysent;
83 syscall_deregister(int *offset, struct sysent *old_sysent)
87 sysent[*offset] = *old_sysent;
92 syscall_module_handler(struct module *mod, int what, void *arg)
94 struct syscall_module_data *data = arg;
100 error = syscall_register(data->offset, data->new_sysent,
103 /* Leave a mark so we know to safely unload below. */
107 ms.intval = *data->offset;
109 module_setspecific(mod, &ms);
112 error = data->chainevh(mod, what, data->chainarg);
116 * MOD_LOAD failed, so just return without calling the
117 * chained handler since we didn't pass along the MOD_LOAD
120 if (data->offset == NULL)
122 if (data->chainevh) {
123 error = data->chainevh(mod, what, data->chainarg);
127 error = syscall_deregister(data->offset, &data->old_sysent);
131 return (data->chainevh(mod, what, data->chainarg));
139 syscall_helper_register(struct syscall_helper_data *sd)
141 struct syscall_helper_data *sd1;
144 for (sd1 = sd; sd1->syscall_no != NO_SYSCALL; sd1++) {
145 error = syscall_register(&sd1->syscall_no, &sd1->new_sysent,
148 syscall_helper_unregister(sd);
157 syscall_helper_unregister(struct syscall_helper_data *sd)
159 struct syscall_helper_data *sd1;
161 for (sd1 = sd; sd1->registered != 0; sd1++) {
162 syscall_deregister(&sd1->syscall_no, &sd1->old_sysent);