NetBSD/sys/kern/kern_lkm.c

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/*
* kern_lkm.c
*
* functions and pseudo-device for loadable kernel modules
*
* 05 Jun 93 Terry Lambert Release cleanup
* 10 Feb 93 Terry Lambert Original
*
* Copyright (c) 1992 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.
*
* $Id: kern_lkm.c,v 1.3 1993/07/19 09:57:22 cgd Exp $
*/
#include "param.h"
#include "systm.h"
#include "ioctl.h"
#include "tty.h"
#include "conf.h"
#include "file.h"
#include "proc.h"
#include "uio.h"
#include "kernel.h"
#include "vnode.h"
#include "malloc.h"
#include "vm/vm.h"
#include "vm/vm_param.h"
#include "vm/vm_kern.h"
#include "mount.h"
#include "exec.h"
#include "lkm.h"
#define PAGESIZE 1024 /* kmem_alloc() allocation quantum*/
#define LKM_ALLOC 0x01
#define LKM_WANT 0x02
#define LKMS_IDLE 0x00
#define LKMS_RESERVED 0x01
#define LKMS_LOADING 0x02
#define LKMS_LOADED 0x04
#define LKMS_UNLOADING 0x08
static int lkm_v = 0;
static int lkm_state = LKMS_IDLE;
#ifndef MAXLKMS
#define MAXLKMS 20
#endif
static struct lkm_table lkmods[ MAXLKMS]; /* table of loaded modules*/
static struct lkm_table *curp; /* global for in-progress ops*/
/*ARGSUSED*/
lkmopen( dev, flag, devtype, p)
dev_t dev;
int flag;
int devtype;
struct proc *p;
{
int error;
if( minor( dev) != 0)
return( ENXIO); /* bad minor #*/
/*
* Use of the loadable kernel module device must be exclusive; we
* may try to remove this restriction later, but it's really no
* hardship.
*/
while( lkm_v & LKM_ALLOC) {
if( flag & FNONBLOCK) /* don't hang*/
return( EBUSY);
lkm_v |= LKM_WANT;
/*
* Sleep pending unlock; we use tsleep() to allow
* an alarm out of the open.
*/
if( error = tsleep( (caddr_t)&lkm_v, TTIPRI|PCATCH, "LKM", 0))
return( error); /* leave LKM_WANT set -- no problem*/
}
lkm_v |= LKM_ALLOC;
return( 0); /* pseudo-device open*/
}
/*
* l k m u n r e s e r v e
*
* Unreserve the memory associated with the current loaded module; done on
* a coerced close of the lkm device (close on premature exit of modload)
* or explicitly by modload as a result of a link failure.
*/
static int
lkmunreserve()
{
if( lkm_state == LKMS_IDLE)
return;
/*
* Actually unreserve the memory
*/
kmem_free( kmem_map, curp->area, curp->size);/**/
lkm_state = LKMS_IDLE;
}
lkmclose( dev, flag, mode, p)
dev_t dev;
int flag;
int mode;
struct proc *p;
{
if( !( lkm_v & LKM_ALLOC)) {
#ifdef DEBUG
printf( "LKM: close before open!\n");
#endif /* DEBUG*/
return( EBADF);
}
/* do this before waking the herd...*/
if( !curp->used) {
/*
* If we close before setting used, we have aborted
* by way of error or by way of close-on-exit from
* a premature exit of "modload".
*/
lkmunreserve(); /* coerce state to LKM_IDLE*/
}
lkm_v &= ~LKM_ALLOC;
wakeup( (caddr_t)&lkm_v); /* thundering herd "problem" here*/
return( 0); /* pseudo-device closed*/
}
/*ARGSUSED*/
lkmioctl( dev, cmd, data, flag)
dev_t dev;
int cmd;
caddr_t data;
int flag;
{
int err = 0;
int i;
struct lmc_resrv *resrvp;
struct lmc_loadbuf *loadbufp;
struct lmc_unload *unloadp;
struct lmc_stat *statp;
int (*funcp)();
char istr[ MAXLKMNAME];
switch( cmd) {
case LMRESERV: /* reserve pages for a module*/
if ((flag & FWRITE) == 0) /* only allow this if writing */
return EPERM;
resrvp = (struct lmc_resrv *)data;
/*
* Find a free slot.
*/
for( i = 0; i < MAXLKMS; i++) {
if( !lkmods[ i].used)
break;
}
if( i == MAXLKMS) {
err = ENOMEM; /* no slots available*/
break;
}
curp = &lkmods[ i];
curp->id = i; /* self reference slot offset*/
resrvp->slot = i; /* return slot*/
/*
* Get memory for module
*/
curp->size = resrvp->size;
curp->area = (char *)kmem_alloc( kmem_map, curp->size);/**/
curp->offset = 0; /* load offset*/
resrvp->addr = (unsigned long)curp->area; /* ret kernel addr*/
#ifdef DEBUG
printf( "LKM: LMRESERV (actual = 0x%08x)\n", curp->area);
printf( "LKM: LMRESERV (adjusted = 0x%08x)\n",
trunc_page(curp->area));
#endif /* DEBUG*/
lkm_state = LKMS_RESERVED;
break;
case LMLOADBUF: /* Copy in; stateful, follows LMRESERV*/
if ((flag & FWRITE) == 0) /* only allow this if writing */
return EPERM;
loadbufp = (struct lmc_loadbuf *)data;
if( lkm_state != LKMS_RESERVED && lkm_state != LKMS_LOADING) {
err = ENOMEM;
break;
}
/* account for odd size (non-page multiple) copyin*/
i = MIN( curp->size - curp->offset, MODIOBUF);
/* copy in buffer full of data*/
if( err = copyin( (caddr_t)loadbufp->data, (caddr_t)curp->area + curp->offset, i))
break;
if( ( curp->offset + i) < curp->size) {
lkm_state = LKMS_LOADING;
#ifdef DEBUG
printf( "LKM: LMLOADBUF (loading @ %d of %d, i = %d)\n",
curp->offset, curp->size, i);
#endif /* DEBUG*/
} else {
lkm_state = LKMS_LOADED;
#ifdef DEBUG
printf( "LKM: LMLOADBUF (loaded)\n");
#endif /* DEBUG*/
}
curp->offset += MODIOBUF;
break;
case LMUNRESRV: /* discard reserved pages for a module*/
if ((flag & FWRITE) == 0) /* only allow this if writing */
return EPERM;
lkmunreserve(); /* coerce state to LKM_IDLE*/
#ifdef DEBUG
printf( "LKM: LMUNRESERV\n");
#endif /* DEBUG*/
break;
case LMREADY: /* module loaded: call entry*/
if ((flag & FWRITE) == 0) /* only allow this if writing */
return EPERM;
if( lkm_state != LKMS_LOADED) {
#ifdef DEBUG
printf( "lkm_state is %02x\n", lkm_state);
#endif /* DEBUG*/
err = ENXIO;
break;
}
curp->entry = (int (*)()) (*((int *) ( data)));
/* call entry(load)... (assigns "private" portion)*/
if( err = (*(curp->entry))( curp, LKM_E_LOAD, LKM_VERSION)) {
/*
* Module may refuse loading or may have a
* version mismatch...
*/
lkm_state = LKMS_UNLOADING; /* for lkmunreserve*/
lkmunreserve(); /* free memory*/
curp->used = 0; /* free slot*/
break;
}
curp->used = 1;
#ifdef DEBUG
printf( "LKM: LMREADY\n");
#endif /* DEBUG*/
lkm_state = LKMS_IDLE;
break;
case LMUNLOAD: /* unload a module*/
if ((flag & FWRITE) == 0) /* only allow this if writing */
return EPERM;
unloadp = (struct lmc_unload *)data;
if( ( i = unloadp->id) == -1) { /* unload by name*/
/*
* Copy name in and lookup id from all loaded
* modules. May fail.
*/
if( err = copyinstr( unloadp->name, istr, MAXLKMNAME-1, NULL))
break;
/*
* look up id...
*/
for( i = 0; i < MAXLKMS; i++) {
if( !lkmods[ i].used)
continue;
if( !strcmp( istr,
lkmods[ i].private.lkm_any->lkm_name))
break;
}
}
/*
* Range check the value; on failure, return EINVAL
*/
if( i < 0 || i >= MAXLKMS) {
err = EINVAL;
break;
}
curp = &lkmods[ i];
/* call entry(unload)*/
if( (*(curp->entry))( curp, LKM_E_UNLOAD, LKM_VERSION)) {
err = EBUSY;
break;
}
lkm_state = LKMS_UNLOADING; /* non-idle for lkmunreserve*/
lkmunreserve(); /* free memory*/
curp->used = 0; /* free slot*/
break;
case LMSTAT: /* stat a module by id/name*/
/* allow readers and writers to stat */
statp = (struct lmc_stat *)data;
if( ( i = statp->id) == -1) { /* stat by name*/
/*
* Copy name in and lookup id from all loaded
* modules. May fail.
*/
if( err = copyinstr( statp->name, istr, MAXLKMNAME-1, NULL))
break;
/*
* look up id...
*/
for( i = 0; i < MAXLKMS; i++) {
if( !lkmods[ i].used)
continue;
if( !strcmp( istr,
lkmods[ i].private.lkm_any->lkm_name))
break;
}
if( i == MAXLKMS) { /* Not found*/
err = ENOENT;
break;
}
}
/*
* Range check the value; on failure, return EINVAL
*/
if( i < 0 || i >= MAXLKMS) {
err = EINVAL;
break;
}
curp = &lkmods[ i];
if( !curp->used) { /* Not found*/
err = ENOENT;
break;
}
/*
* Copy out stat information for this module...
*/
statp->id = curp->id;
statp->offset = curp->private.lkm_any->lkm_offset;
statp->type = curp->private.lkm_any->lkm_type;
statp->area = curp->area;
statp->size = curp->size / PAGESIZE;
statp->private = (unsigned long)curp->private.lkm_any;
statp->ver = curp->private.lkm_any->lkm_ver;
err = copyoutstr( curp->private.lkm_any->lkm_name,
statp->name,
MAXLKMNAME - 2,
NULL);
break;
default: /* bad ioctl()...*/
err = ENOTTY;
break;
}
return (err);
}
/*********************************************************************/
/*
* l k m n o s y s
*
* Acts like "nosys" but can be identified in sysent for dynamic call
* number assignment for a limited number of calls.
*
* Place holder for system call slots reserved for loadable modules.
*/
lkmnosys()
{
return( nosys());
}
/*
* l k m e n o d e v
*
* Acts like "enodev", but can be identified in cdevsw and bdevsw for
* dynamic driver major number assignment for a limited number of
* drivers.
*
* Place holder for device switch slots reserved for loadable modules.
*/
int
lkmenodev()
{
return( enodev());
}
/*********************************************************************/
int
lkmexists( lkmtp)
struct lkm_table *lkmtp;
{
int i;
/*
* see if name exists...
*/
for( i = 0; i < MAXLKMS; i++) {
/*
* An unused module and the one we are testing are not
* considered.
*/
if( !lkmods[ i].used || &lkmods[ i] == lkmtp)
continue;
if( !strcmp( lkmtp->private.lkm_any->lkm_name,
lkmods[ i].private.lkm_any->lkm_name))
return( 1); /* already loaded...*/
}
return( 0); /* module not loaded...*/
}
/*
* For the loadable system call described by the structure pointed to
* by lkmtp, load/unload/stat it depending on the cmd requested.
*/
static int
_lkm_syscall( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
struct lkm_syscall *args = lkmtp->private.lkm_syscall;
int i;
int err = 0;
extern int nsysent; /* init_sysent.c*/
switch( cmd) {
case LKM_E_LOAD:
/* don't load twice!*/
if( lkmexists( lkmtp))
return( EEXIST);
if( ( i = args->lkm_offset) == -1) { /* auto*/
/*
* Search the table looking for a slot...
*/
for( i = 0; i < nsysent; i++)
if( sysent[ i].sy_call == lkmnosys)
break; /* found it!*/
/* out of allocable slots?*/
if( i == nsysent) {
err = ENFILE;
break;
}
} else { /* assign*/
if( i < 0 || i >= nsysent) {
err = EINVAL;
break;
}
}
/* save old*/
bcopy( &sysent[ i], &(args->lkm_oldent), sizeof( struct sysent));
/* replace with new*/
bcopy( args->lkm_sysent, &sysent[ i], sizeof( struct sysent));
/* done!*/
args->lkm_offset = i; /* slot in sysent[]*/
break;
case LKM_E_UNLOAD:
/* current slot...*/
i = args->lkm_offset;
/* replace current slot contents with old contents*/
bcopy( &(args->lkm_oldent), &sysent[ i], sizeof( struct sysent));
break;
case LKM_E_STAT: /* no special handling...*/
break;
}
return( err);
}
/*
* For the loadable virtual file system described by the structure pointed
* to by lkmtp, load/unload/stat it depending on the cmd requested.
*/
static int
_lkm_vfs( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
struct lkm_vfs *args = lkmtp->private.lkm_vfs;
int i;
int err = 0;
switch( cmd) {
case LKM_E_LOAD:
/* don't load twice!*/
if( lkmexists( lkmtp))
return( EEXIST);
/*
* Currently, the VFS and mount code in 386BSD is malformed;
* this means that the per volume file system identifier is
* the index into the table rather than the name; this means
* that only the file systems already known to 386BSD are
* allowable, since all others don't have fixed offsets.
* Interestingly, Dell UNIX has this same bug with their VFS
* implementation, but generic AT&T SVR4 does not.
*
* I will correct the VFS code when I get a chance.
*/
i = args->lkm_offset;
if( i < 0 || i > MOUNT_MAXTYPE) {
err = EINVAL;
break;
}
if( vfssw[ i] != (struct vfsops *)0) {
err = EEXIST;
break;
}
/*
* Set up file system
*/
vfssw[ i] = args->lkm_vfsops;
/*
* Call init function for this VFS...
*/
( *(vfssw[ i]->vfs_init))( args->lkm_flags);
/* done!*/
args->lkm_offset = i; /* slot in sysent[]*/
break;
case LKM_E_UNLOAD:
/* current slot...*/
i = args->lkm_offset;
/* replace current slot contents with old contents*/
vfssw[ i] = (struct vfsops *)0;
break;
case LKM_E_STAT: /* no special handling...*/
break;
}
return( err);
}
/*
* For the loadable device driver described by the structure pointed to
* by lkmtp, load/unload/stat it depending on the cmd requested.
*/
static int
_lkm_dev( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
struct lkm_dev *args = lkmtp->private.lkm_dev;
int i;
int err = 0;
extern int nblkdev; /* i386/i386/conf.c*/
extern int nchrdev; /* i386/i386/conf.c*/
switch( cmd) {
case LKM_E_LOAD:
/* don't load twice!*/
if( lkmexists( lkmtp))
return( EEXIST);
switch( args->lkm_devtype) {
case LM_DT_BLOCK:
if( ( i = args->lkm_offset) == -1) { /* auto*/
/*
* Search the table looking for a slot...
*/
for( i = 0; i < nblkdev; i++)
if( bdevsw[ i].d_open == lkmenodev)
break; /* found it!*/
/* out of allocable slots?*/
if( i == nblkdev) {
err = ENFILE;
break;
}
} else { /* assign*/
if( i < 0 || i >= nblkdev) {
err = EINVAL;
break;
}
}
/* save old*/
bcopy( &bdevsw[ i], &(args->lkm_olddev.bdev), sizeof( struct bdevsw));
/* replace with new*/
bcopy( args->lkm_dev.bdev, &bdevsw[ i], sizeof( struct bdevsw));
/* done!*/
args->lkm_offset = i; /* slot in bdevsw[]*/
break;
case LM_DT_CHAR:
if( ( i = args->lkm_offset) == -1) { /* auto*/
/*
* Search the table looking for a slot...
*/
for( i = 0; i < nchrdev; i++)
if( cdevsw[ i].d_open == lkmenodev)
break; /* found it!*/
/* out of allocable slots?*/
if( i == nchrdev) {
err = ENFILE;
break;
}
} else { /* assign*/
if( i < 0 || i >= nchrdev) {
err = EINVAL;
break;
}
}
/* save old*/
bcopy( &cdevsw[ i], &(args->lkm_olddev.cdev), sizeof( struct cdevsw));
/* replace with new*/
bcopy( args->lkm_dev.cdev, &cdevsw[ i], sizeof( struct cdevsw));
/* done!*/
args->lkm_offset = i; /* slot in cdevsw[]*/
break;
default:
err = ENODEV;
break;
}
break;
case LKM_E_UNLOAD:
/* current slot...*/
i = args->lkm_offset;
switch( args->lkm_devtype) {
case LM_DT_BLOCK:
/* replace current slot contents with old contents*/
bcopy( &(args->lkm_olddev.bdev), &bdevsw[ i], sizeof( struct bdevsw));
break;
case LM_DT_CHAR:
/* replace current slot contents with old contents*/
bcopy( &(args->lkm_olddev.cdev), &cdevsw[ i], sizeof( struct cdevsw));
break;
default:
err = ENODEV;
break;
}
break;
case LKM_E_STAT: /* no special handling...*/
break;
}
return( err);
}
#ifdef STREAMS
/*
* For the loadable streams module described by the structure pointed to
* by lkmtp, load/unload/stat it depending on the cmd requested.
*/
static int
_lkm_strmod( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
struct lkm_strmod *args = lkmtp->private.lkm_strmod;
int i;
int err = 0;
switch( cmd) {
case LKM_E_LOAD:
/* don't load twice!*/
if( lkmexists( lkmtp))
return( EEXIST);
break;
case LKM_E_UNLOAD:
break;
case LKM_E_STAT: /* no special handling...*/
break;
}
return( err);
}
#endif /* STREAMS*/
#ifdef LKM_EXEC /* XXX NOTDEF YET!!! - cgd */
/*
* For the loadable execution class described by the structure pointed to
* by lkmtp, load/unload/stat it depending on the cmd requested.
*/
static int
_lkm_exec( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
struct lkm_exec *args = lkmtp->private.lkm_exec;
int i;
int err = 0;
switch( cmd) {
case LKM_E_LOAD:
/* don't load twice!*/
if( lkmexists( lkmtp))
return( EEXIST);
if( ( i = args->lkm_offset) == -1) { /* auto*/
/*
* Search the table looking for a slot...
*/
for( i = 0; i < nexecs; i++)
if( execsw[ i].m_size == 0)
break; /* found it!*/
/* out of allocable slots?*/
if( i == nexecs) {
err = ENFILE;
break;
}
} else { /* assign*/
if( i < 0 || i >= nexecs) {
err = EINVAL;
break;
}
}
/* save old*/
bcopy( &execsw[ i], &(args->lkm_oldexec), sizeof( struct execsw));
/* replace with new*/
bcopy( args->lkm_exec, &execsw[ i], sizeof( struct execsw));
/* done!*/
args->lkm_offset = i; /* slot in execsw[]*/
break;
case LKM_E_UNLOAD:
/* current slot...*/
i = args->lkm_offset;
/* replace current slot contents with old contents*/
bcopy( &execsw[ i], &(args->lkm_oldexec), sizeof( struct execsw));
break;
case LKM_E_STAT: /* no special handling...*/
break;
}
return( err);
}
#endif /* LKM_EXEC */
/*
* This code handles the per-module type "wiring-in" of loadable modules
* into existing kernel tables. For "LM_MISC" modules, wiring and unwiring
* is assumed to be done in their entry routines internal to the module
* itself.
*/
lkmdispatch( lkmtp, cmd)
struct lkm_table *lkmtp;
int cmd;
{
int err = 0; /* default = success*/
switch( lkmtp->private.lkm_any->lkm_type) {
case LM_SYSCALL:
err = _lkm_syscall( lkmtp, cmd);
break;
case LM_VFS:
err = _lkm_vfs( lkmtp, cmd);
break;
case LM_DEV:
{
struct lkm_dev *args = lkmtp->private.lkm_dev;
}
break;
#ifdef STREAMS
case LM_STRMOD:
{
struct lkm_strmod *args = lkmtp->private.lkm_strmod;
}
break;
#endif /* STREAMS*/
#ifdef LKM_EXEC
case LM_EXEC:
err = _lkm_exec( lkmtp, cmd);
break;
#endif /* LKM_EXEC */
case LM_MISC: /* ignore content -- no "misc-specific" procedure*/
break;
default:
err = ENXIO; /* unknown type*/
break;
}
return( err);
}