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>
31 #include <sys/sysproto.h>
32 #include <sys/sysent.h>
33 #include <sys/syscall.h>
35 #include <sys/mutex.h>
37 #include <sys/module.h>
40 * Acts like "nosys" but can be identified in sysent for dynamic call
41 * number assignment for a limited number of calls.
43 * Place holder for system call slots reserved for loadable modules.
46 lkmnosys(struct thread *td, struct nosys_args *args)
48 return(nosys(td, args));
52 lkmressys(struct thread *td, struct nosys_args *args)
54 return(nosys(td, args));
58 syscall_register(int *offset, struct sysent *new_sysent,
59 struct sysent *old_sysent)
61 if (*offset == NO_SYSCALL) {
64 for (i = 1; i < SYS_MAXSYSCALL; ++i)
65 if (sysent[i].sy_call == (sy_call_t *)lkmnosys)
67 if (i == SYS_MAXSYSCALL)
70 } else if (*offset < 0 || *offset >= SYS_MAXSYSCALL)
72 else if (sysent[*offset].sy_call != (sy_call_t *)lkmnosys &&
73 sysent[*offset].sy_call != (sy_call_t *)lkmressys)
76 *old_sysent = sysent[*offset];
77 sysent[*offset] = *new_sysent;
82 syscall_deregister(int *offset, struct sysent *old_sysent)
85 sysent[*offset] = *old_sysent;
90 syscall_module_handler(struct module *mod, int what, void *arg)
92 struct syscall_module_data *data = (struct syscall_module_data*)arg;
98 error = syscall_register(data->offset, data->new_sysent,
102 ms.intval = *data->offset;
104 module_setspecific(mod, &ms);
107 error = data->chainevh(mod, what, data->chainarg);
111 if (data->chainevh) {
112 error = data->chainevh(mod, what, data->chainarg);
116 error = syscall_deregister(data->offset, &data->old_sysent);
124 return data->chainevh(mod, what, data->chainarg);