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mirror of https://git.FreeBSD.org/src.git synced 2025-01-18 15:30:21 +00:00

Implement support for adding syscalls in KLD modules.

Submitted by: Assar Westerlund <assar@sics.se>
This commit is contained in:
Doug Rabson 1999-01-09 14:15:41 +00:00
parent b9c576c894
commit 4c3df79450
Notes: svn2git 2020-12-20 02:59:44 +00:00
svn path=/head/; revision=42433
2 changed files with 126 additions and 2 deletions

94
sys/kern/kern_syscalls.c Normal file
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@ -0,0 +1,94 @@
/*-
* 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.
*
* $Id: kern_syscalls.c,v 1.1 1999/01/03 06:00:55 root Exp root $
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/sysproto.h>
#include <sys/sysent.h>
#include <sys/syscall.h>
#include <sys/module.h>
#include <sys/linker.h>
#include <sys/proc.h>
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)
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;
int error;
switch (what) {
case MOD_LOAD :
error = syscall_register(data->offset, data->new_sysent,
&data->old_sysent);
if (error)
return error;
break;
case MOD_UNLOAD :
error = syscall_deregister(data->offset, &data->old_sysent);
if (error)
return error;
break;
}
if (data->chainevh)
return data->chainevh(mod, what, data->chainarg);
else
return 0;
}

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@ -30,7 +30,7 @@
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $Id: sysent.h,v 1.18 1998/06/07 17:13:03 dfr Exp $
* $Id: sysent.h,v 1.19 1998/09/14 05:36:51 jdp Exp $
*/
#ifndef _SYS_SYSENT_H_
@ -76,6 +76,36 @@ struct sysentvec {
#ifdef KERNEL
extern struct sysentvec aout_sysvec;
extern struct sysent sysent[];
#endif
#define NO_SYSCALL (-1)
struct module;
struct syscall_module_data {
int (*chainevh)(struct module *, int, void *); /* next handler */
void *chainarg; /* arg for next event handler */
int *offset; /* offset into sysent */
struct sysent *new_sysent; /* new sysent */
struct sysent old_sysent; /* old sysent */
};
#define SYSCALL_MODULE(name, offset, new_sysent, evh, arg) \
static struct syscall_module_data name##_syscall_mod = { \
evh, arg, offset, new_sysent \
}; \
\
static moduledata_t name##_mod = { \
#name, \
syscall_module_handler, \
&name##_syscall_mod \
}; \
DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS, SI_ORDER_MIDDLE)
int syscall_register __P((int *offset, struct sysent *new_sysent,
struct sysent *old_sysent));
int syscall_deregister __P((int *offset, struct sysent *old_sysent));
int syscall_module_handler __P((struct module *mod, int what, void *arg));
#endif /* KERNEL */
#endif /* !_SYS_SYSENT_H_ */