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/*-
* Copyright (c) 2001 Networks Associates Technologies, Inc.
* All rights reserved.
*
* This software was developed for the FreeBSD Project by NAI Labs, the
* Security Research Division of Network Associates, Inc. under
* DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA
* CHATS research program.
*
* 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.
* 3. The name of the author may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* 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.
*
* $Id$
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/syscall.h>
#include <sys/sysent.h>
#include <machine/frame.h>
#include "syscall_gate.h"
void syscall_gate_init(void);
int syscall_gate(struct thread *td, caddr_t params);
static struct syscall_gate sg;
void
syscall_gate_init(void) {
sg.sg_table = curthread->td_proc->p_sysent->sv_table;
bzero(sg.sg_oldsyscalls, sizeof(sg.sg_oldsyscalls));
}
int
syscall_gate_register(int offset, sy_call_t *call, int narg, int mpsafe) {
struct sysent *se;
int error = 0;
if (offset <= 0 || offset >= SYS_MAXSYSCALL) {
error = EINVAL;
goto out;
}
if (sg.sg_oldsyscalls[offset].sy_call != NULL) {
error = EEXIST;
goto out;
}
se = &sg.sg_table[offset];
sg.sg_oldsyscalls[offset] = *se;
se->sy_call = (sy_call_t *)call;
se->sy_narg = narg | (mpsafe ? SYF_MPSAFE : 0);
out:
return (error);
}
void
syscall_gate_deregister(int offset) {
KASSERT(offset > 0 && offset < SYS_MAXSYSCALL, ("syscall offset %d out of range",
offset));
KASSERT(sg.sg_oldsyscalls[offset].sy_call != NULL, ("deregistering nonexistant syscall %d",
offset));
sg.sg_table[offset] = sg.sg_oldsyscalls[offset];
sg.sg_oldsyscalls[offset].sy_call = NULL;
sg.sg_oldsyscalls[offset].sy_narg = 0;
}
static int
syscall_gate_modevent(module_t module, int event, void *unused) {
int i;
switch ((enum modeventtype)event) {
case MOD_LOAD:
syscall_gate_init();
break;
case MOD_UNLOAD:
for (i = 1; i < SYS_MAXSYSCALL; i++) {
struct sysent *se;
se = &sg.sg_oldsyscalls[i];
if (se->sy_call != NULL)
sg.sg_table[i] = *se;
}
break;
case MOD_SHUTDOWN:
break;
}
return (0);
}
static moduledata_t syscall_gate_moduledata = {
"syscall_gate",
&syscall_gate_modevent,
NULL
};
DECLARE_MODULE(syscall_gate, syscall_gate_moduledata, SI_SUB_DRIVERS, SI_ORDER_ANY);
MODULE_VERSION(syscall_gate, 1);
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