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/* $OpenBSD: miscmod.c,v 1.3 2000/03/02 14:46:36 todd Exp $ */
/*
* Makefile for miscmod
*
* 05 Jun 93 Terry Lambert Split mycall.c out
* 25 May 93 Terry Lambert Original
*
* Copyright (c) 1993 Terrence R. Lambert.
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Terrence R. Lambert.
* 4. The name Terrence R. Lambert may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY TERRENCE R. LAMBERT ``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 TERRENCE R. LAMBERT 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/param.h>
#include <sys/ioctl.h>
#include <sys/systm.h>
#include <sys/conf.h>
#include <sys/mount.h>
#include <sys/exec.h>
#include <sys/lkm.h>
#include <sys/file.h>
#include <sys/errno.h>
#include <sys/syscall.h>
extern int misccall();
/*
* These two entries define our system call and module information. We
* have 0 arguments to our system call.
*/
static struct sysent newent = {
0, 0, misccall /* # of args, args size, fn pointer*/
};
/*
* Miscellaneous modules must have their own save areas...
*/
static struct sysent oldent; /* save are for old callslot entry*/
MOD_MISC( "miscmod")
/*
* This function is called each time the module is loaded or unloaded.
* Since we are a miscellaneous module, we have to provide whatever
* code is necessary to patch ourselves into the area we are being
* loaded to change.
*
* For the system call table, we duplicate the code in the kern_lkm.c
* file for patching into the system call table. We can tell what
* has been allocated, etc. by virtue of the fact that we know the
* criteria used by the system call loader interface. We still
* kick out the copyright to the console here (to give an example).
*
* The stat information is basically common to all modules, so there
* is no real issue involved with stat; we will leave it lkm_nofunc(),
* since we don't have to do anything about it.
*/
static int
miscmod_handle( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
int i;
struct lkm_misc *args = lkmtp->private.lkm_misc;
int err = 0; /* default = success*/
extern int sys_lkmnosys(); /* allocable slot*/
switch( cmd) {
case LKM_E_LOAD:
/*
* Don't load twice! (lkmexists() is exported by kern_lkm.c)
*/
if( lkmexists( lkmtp))
return( EEXIST);
/*
* This is where we would express a slot preference if
* we had one; since we don't, we will simply duplicate
* the "auto" code and forget the other.
*/
/*
* Search the table looking for a slot...
*/
for( i = 0; i < SYS_MAXSYSCALL; i++)
if( sysent[ i].sy_call == sys_lkmnosys)
break; /* found it!*/
/* out of allocable slots?*/
if( i == SYS_MAXSYSCALL) {
err = ENFILE;
break;
}
/* save old -- we must provide our own data area*/
bcopy( &sysent[ i], &oldent, sizeof( struct sysent));
/* replace with new*/
bcopy( &newent, &sysent[ i], sizeof( struct sysent));
/* done!*/
args->lkm_offset = i; /* slot in sysent[]*/
/* if we make it to here, print copyright on console*/
printf( "\nSample Loaded miscellaneous module (system call)\n");
printf( "Copyright (c) 1993\n");
printf( "Terrence R. Lambert\n");
printf( "All rights reserved\n");
break; /* Success*/
case LKM_E_UNLOAD:
/* current slot...*/
i = args->lkm_offset;
/* replace current slot contents with old contents*/
bcopy( &oldent, &sysent[ i], sizeof( struct sysent));
break; /* Success*/
default: /* we only understand load/unload*/
err = EINVAL;
break;
}
return( err);
}
/*
* External entry point; should generally match name of .o file. The
* arguments are always the same for all loaded modules. The "load",
* "unload", and "stat" functions in "DISPATCH" will be called under
* their respective circumstances. If no function is desired, lkm_nofunc()
* should be supplied. They are called with the same arguments (cmd is
* included to allow the use of a single function, ver is included for
* version matching between modules and the kernel loader for the modules).
*
* Since we expect to link in the kernel and add external symbols to
* the kernel symbol name space in a future version, generally all
* functions used in the implementation of a particular module should
* be static unless they are expected to be seen in other modules or
* to resolve unresolved symbols alread existing in the kernel (the
* second case is not likely to ever occur).
*
* The entry point should return 0 unless it is refusing load (in which
* case it should return an errno from errno.h).
*/
miscmod( lkmtp, cmd, ver)
struct lkm_table *lkmtp;
int cmd;
int ver;
{
DISPATCH(lkmtp,cmd,ver,miscmod_handle,miscmod_handle,lkm_nofunc)
}
/*
* EOF -- This file has not been truncated.
*/
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