File: [local] / sys / kern / kern_lkm.c (download)
Revision 1.1, Tue Mar 4 16:14:53 2008 UTC (16 years, 4 months ago) by nbrk
Branch point for: MAIN
Initial revision
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/* $OpenBSD: kern_lkm.c,v 1.43 2006/11/15 17:25:40 jmc Exp $ */
/* $NetBSD: kern_lkm.c,v 1.31 1996/03/31 21:40:27 christos Exp $ */
/*
* Copyright (c) 1994 Christopher G. Demetriou
* 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.
*/
/*
* XXX it's not really safe to unload *any* of the types which are
* currently loadable; e.g. you could unload a syscall which was being
* blocked in, etc. In the long term, a solution should be come up
* with, but "not right now." -- cgd
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/tty.h>
#include <sys/file.h>
#include <sys/proc.h>
#include <sys/uio.h>
#include <sys/kernel.h>
#include <sys/vnode.h>
#include <sys/malloc.h>
#include <sys/mount.h>
#include <sys/exec.h>
#include <sys/syscallargs.h>
#include <sys/conf.h>
#include <sys/lkm.h>
#include <sys/syscall.h>
#include <uvm/uvm_extern.h>
#ifdef DDB
#include <machine/db_machdep.h>
#include <ddb/db_sym.h>
#endif
/* flags */
#define LKM_ALLOC 0x01
#define LKM_WANT 0x02
#define LKM_INIT 0x04
#define LKMS_IDLE 0x00
#define LKMS_RESERVED 0x01
#define LKMS_LOADING 0x02
#define LKMS_LOADING_SYMS 0x03
#define LKMS_LOADED 0x04
#define LKMS_UNLOADING 0x08
static int lkm_v = 0;
static int lkm_state = LKMS_IDLE;
static TAILQ_HEAD(lkmods, lkm_table) lkmods; /* table of loaded modules */
static struct lkm_table *curp; /* global for in-progress ops */
static struct lkm_table *lkmalloc(void);
static void lkmfree(struct lkm_table *);
static struct lkm_table *lkmlookup(int, char *, int *);
static void lkmunreserve(void);
static int _lkm_syscall(struct lkm_table *, int);
static int _lkm_vfs(struct lkm_table *, int);
static int _lkm_dev(struct lkm_table *, int);
static int _lkm_exec(struct lkm_table *, int);
void lkminit(void);
int lkmexists(struct lkm_table *);
void init_exec(void);
void
lkminit(void)
{
TAILQ_INIT(&lkmods);
lkm_v |= LKM_INIT;
}
/*ARGSUSED*/
int
lkmopen(dev_t dev, int flag, int devtype, struct proc *p)
{
int error;
if (minor(dev) != 0)
return (ENXIO);
if (!(lkm_v & LKM_INIT))
lkminit();
/*
* 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.
*/
error = tsleep(&lkm_v, TTIPRI|PCATCH, "lkmopn", 0);
if (error)
return (error); /* leave LKM_WANT set -- no problem */
}
lkm_v |= LKM_ALLOC;
return (0); /* pseudo-device open */
}
/*
* Alocates new LKM table entry, fills module id, inserts in the list.
* Returns NULL on failure.
*
*/
static struct lkm_table *
lkmalloc(void)
{
struct lkm_table *p, *ret = NULL;
int id = 0;
MALLOC(ret, struct lkm_table *, sizeof(*ret), M_DEVBUF, M_WAITOK);
ret->refcnt = ret->depcnt = 0;
ret->sym_id = -1;
/*
* walk the list finding the first free id. as long as the list is
* kept sorted this is not too inefficient, which is why we insert in
* order below.
*/
TAILQ_FOREACH(p, &lkmods, list) {
if (id == p->id)
id++;
else
break;
}
ret->id = id;
if (p == NULL) /* either first or last entry */
TAILQ_INSERT_TAIL(&lkmods, ret, list);
else
TAILQ_INSERT_BEFORE(p, ret, list);
return ret;
}
/*
* Frees the slot, decreases the number of modules.
*/
static void
lkmfree(struct lkm_table *p)
{
TAILQ_REMOVE(&lkmods, p, list);
free(p, M_DEVBUF);
curp = NULL;
}
struct lkm_table *
lkm_list(struct lkm_table *p)
{
if (p == NULL)
p = TAILQ_FIRST(&lkmods);
else
p = TAILQ_NEXT(p, list);
return (p);
}
static struct lkm_table *
lkmlookup(int i, char *name, int *error)
{
struct lkm_table *p = NULL;
char istr[MAXLKMNAME];
/*
* p being NULL here implies the list is empty, so any lookup is
* invalid (name based or otherwise). Since the list of modules is
* kept sorted by id, lowest to highest, the id of the last entry
* will be the highest in use.
*/
p = TAILQ_LAST(&lkmods, lkmods);
if (p == NULL || i > p->id) {
*error = EINVAL;
return NULL;
}
if (i < 0) { /* unload by name */
/*
* Copy name and lookup id from all loaded
* modules. May fail.
*/
*error = copyinstr(name, istr, MAXLKMNAME-1, NULL);
if (*error)
return NULL;
istr[MAXLKMNAME-1] = '\0';
TAILQ_FOREACH(p, &lkmods, list) {
if (!strcmp(istr, p->private.lkm_any->lkm_name))
break;
}
} else
TAILQ_FOREACH(p, &lkmods, list)
if (i == p->id)
break;
if (p == NULL)
*error = ENOENT;
return p;
}
/*
* 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 void
lkmunreserve(void)
{
if (lkm_state == LKMS_IDLE)
return;
#ifdef DDB
if (curp && curp->sym_id != -1)
db_del_symbol_table(curp->private.lkm_any->lkm_name);
#endif
if (curp && curp->syms) {
uvm_km_free(kernel_map, (vaddr_t)curp->syms, curp->sym_size);
curp->syms = NULL;
}
/*
* Actually unreserve the memory
*/
if (curp && curp->area) {
uvm_km_free(kernel_map, curp->area, curp->size);
curp->area = 0;
}
lkm_state = LKMS_IDLE;
}
int
lkmclose(dev_t dev, int flag, int mode, struct proc *p)
{
if (minor(dev) != 0)
return (ENXIO);
if (!(lkm_v & LKM_ALLOC))
return (EBADF);
/* do this before waking the herd... */
if (curp != NULL && !curp->refcnt) {
/*
* 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();
lkmfree(curp);
}
lkm_v &= ~LKM_ALLOC;
wakeup(&lkm_v); /* thundering herd "problem" here */
return (0);
}
/*ARGSUSED*/
int
lkmioctl(dev_t dev, u_long cmd, caddr_t data, int flags, struct proc *p)
{
int error = 0;
if (securelevel > 0) {
switch (cmd) {
case LMSTAT:
break;
default:
return (EPERM);
}
}
if (!(flags & FWRITE)) {
switch (cmd) {
case LMSTAT:
break;
default:
return (EACCES);
}
}
switch (cmd) {
case LMRESERV:
case LMRESERV_O: {
struct lmc_resrv *resrvp = (struct lmc_resrv *)data;
if ((curp = lkmalloc()) == NULL) {
error = ENOMEM;
break;
}
curp->ver = (cmd == LMRESERV) ? LKM_VERSION : LKM_OLDVERSION;
resrvp->slot = curp->id; /* return slot */
/*
* Get memory for module
*/
curp->size = resrvp->size;
curp->area = uvm_km_zalloc(kernel_map, curp->size);
curp->offset = 0;
resrvp->addr = curp->area;
if (cmd == LMRESERV && resrvp->sym_size) {
curp->sym_size = resrvp->sym_size;
curp->sym_symsize = resrvp->sym_symsize;
curp->syms = (caddr_t)uvm_km_zalloc(kernel_map,
curp->sym_size);
curp->sym_offset = 0;
resrvp->sym_addr = curp->syms;
} else {
curp->sym_size = 0;
curp->syms = 0;
curp->sym_offset = 0;
if (cmd == LMRESERV)
resrvp->sym_addr = 0;
}
#ifdef LKM_DEBUG
printf("LKM: LMRESERV (actual = 0x%08lx)\n", curp->area);
printf("LKM: LMRESERV (syms = 0x%08x)\n", curp->syms);
printf("LKM: LMRESERV (adjusted = 0x%08lx)\n",
trunc_page(curp->area));
#endif /* LKM_DEBUG */
lkm_state = LKMS_RESERVED;
break;
}
case LMLOADBUF: {
struct lmc_loadbuf *loadbufp = (struct lmc_loadbuf *)data;
if ((lkm_state != LKMS_RESERVED && lkm_state != LKMS_LOADING)
|| loadbufp->cnt < 0
|| loadbufp->cnt > MODIOBUF
|| loadbufp->cnt > (curp->size - curp->offset)) {
error = ENOMEM;
break;
}
/* copy in buffer full of data */
error = copyin(loadbufp->data,
(caddr_t)curp->area + curp->offset, loadbufp->cnt);
if (error)
break;
if ((curp->offset + loadbufp->cnt) < curp->size)
lkm_state = LKMS_LOADING;
else
lkm_state = LKMS_LOADING_SYMS;
curp->offset += loadbufp->cnt;
break;
}
case LMLOADSYMS: {
struct lmc_loadbuf *loadbufp = (struct lmc_loadbuf *)data;
if ((lkm_state != LKMS_LOADING &&
lkm_state != LKMS_LOADING_SYMS)
|| loadbufp->cnt < 0
|| loadbufp->cnt > MODIOBUF
|| loadbufp->cnt > (curp->sym_size - curp->sym_offset)) {
error = ENOMEM;
break;
}
/* copy in buffer full of data*/
error = copyin(loadbufp->data, curp->syms +
curp->sym_offset, loadbufp->cnt);
if (error)
break;
if ((curp->sym_offset + loadbufp->cnt) < curp->sym_size)
lkm_state = LKMS_LOADING_SYMS;
else
lkm_state = LKMS_LOADED;
curp->sym_offset += loadbufp->cnt;
break;
}
case LMUNRESRV:
lkmunreserve();
if (curp)
lkmfree(curp);
break;
case LMREADY:
switch (lkm_state) {
case LKMS_LOADED:
break;
case LKMS_LOADING:
case LKMS_LOADING_SYMS:
if ((curp->size - curp->offset) > 0)
/* The remainder must be bss, so we clear it */
bzero((caddr_t)curp->area + curp->offset,
curp->size - curp->offset);
break;
default:
return (ENXIO);
}
curp->entry = (int (*)(struct lkm_table *, int, int))
(*((long *) (data)));
#ifdef LKM_DEBUG
printf("LKM: call entrypoint %x\n", curp->entry);
#endif /* LKM_DEBUG */
/* call entry(load)... (assigns "private" portion) */
error = (*(curp->entry))(curp, LKM_E_LOAD, curp->ver);
if (error) {
/*
* Module may refuse loading or may have a
* version mismatch...
*/
lkm_state = LKMS_UNLOADING; /* for lkmunreserve */
lkmunreserve(); /* free memory */
lkmfree(curp); /* free slot */
break;
}
#ifdef LKM_DEBUG
printf("LKM: LMREADY, id=%d, dev=%d\n", curp->id,
curp->private.lkm_any->lkm_offset);
#endif /* LKM_DEBUG */
#ifdef DDB
if (curp->syms && curp->sym_offset >= curp->sym_size) {
curp->sym_id = db_add_symbol_table(curp->syms,
curp->syms + curp->sym_symsize,
curp->private.lkm_any->lkm_name,
curp->syms);
printf("DDB symbols added: %ld bytes\n",
curp->sym_symsize);
}
#endif /* DDB */
curp->refcnt++;
lkm_state = LKMS_IDLE;
break;
case LMUNLOAD: {
struct lmc_unload *unloadp = (struct lmc_unload *)data;
curp = lkmlookup(unloadp->id, unloadp->name, &error);
if (curp == NULL)
break;
/* call entry(unload) */
if ((*(curp->entry))(curp, LKM_E_UNLOAD, curp->ver)) {
error = EBUSY;
break;
}
lkm_state = LKMS_UNLOADING; /* non-idle for lkmunreserve */
lkmunreserve(); /* free memory */
lkmfree(curp); /* free slot */
break;
}
case LMSTAT: {
struct lmc_stat *statp = (struct lmc_stat *)data;
if ((curp = lkmlookup(statp->id, statp->name, &error)) == NULL)
break;
if ((error = (*curp->entry)(curp, LKM_E_STAT, curp->ver)))
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 / PAGE_SIZE;
statp->private = (unsigned long)curp->private.lkm_any;
statp->ver = curp->private.lkm_any->lkm_ver;
copyoutstr(curp->private.lkm_any->lkm_name,
statp->name, MAXLKMNAME, NULL);
break;
}
default:
error = ENODEV;
break;
}
return (error);
}
/*
* 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.
*/
int
sys_lkmnosys(struct proc *p, void *v, register_t *retval)
{
return (sys_nosys(p, v, retval));
}
/*
* 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(void)
{
return (enodev());
}
/*
* A placeholder function for load/unload/stat calls; simply returns zero.
* Used where people don't want to specify a special function.
*/
int
lkm_nofunc(struct lkm_table *lkmtp, int cmd)
{
return (0);
}
int
lkmexists(struct lkm_table *lkmtp)
{
struct lkm_table *p;
TAILQ_FOREACH(p, &lkmods, list) {
if (!strcmp(lkmtp->private.lkm_any->lkm_name,
p->private.lkm_any->lkm_name) && p->refcnt)
return (1);
}
return (0);
}
/*
* 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(struct lkm_table *lkmtp, int cmd)
{
struct lkm_syscall *args = lkmtp->private.lkm_syscall;
int i;
int error = 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 < SYS_MAXSYSCALL; i++)
if (sysent[i].sy_call == sys_lkmnosys)
break; /* found it! */
/* out of allocable slots? */
if (i == SYS_MAXSYSCALL) {
error = ENFILE;
break;
}
} else { /* assign */
if (i < 0 || i >= SYS_MAXSYSCALL) {
error = 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 (error);
}
/*
* 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(struct lkm_table *lkmtp, int cmd)
{
int error = 0;
struct lkm_vfs *args = lkmtp->private.lkm_vfs;
switch (cmd) {
case LKM_E_LOAD:
/* don't load twice! */
if (lkmexists(lkmtp))
return (EEXIST);
error = vfs_register(args->lkm_vfsconf);
break;
case LKM_E_UNLOAD:
error = vfs_unregister(args->lkm_vfsconf);
break;
case LKM_E_STAT: /* no special handling... */
break;
}
return (error);
}
/*
* 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(struct lkm_table *lkmtp, int cmd)
{
struct lkm_dev *args = lkmtp->private.lkm_dev;
int i;
int error = 0;
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 ==
(dev_type_open((*))) lkmenodev)
break; /* found it! */
/* out of allocable slots? */
if (i == nblkdev) {
error = ENFILE;
break;
}
} else { /* assign */
if (i < 0 || i >= nblkdev) {
error = 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 ==
(dev_type_open((*))) lkmenodev)
break; /* found it! */
/* out of allocable slots? */
if (i == nchrdev) {
error = ENFILE;
break;
}
} else { /* assign */
if (i < 0 || i >= nchrdev) {
error = 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:
error = 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:
error = ENODEV;
break;
}
break;
case LKM_E_STAT: /* no special handling... */
break;
}
return (error);
}
/*
* 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(struct lkm_table *lkmtp, int cmd)
{
struct lkm_exec *args = lkmtp->private.lkm_exec;
int i;
int error = 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].es_check == NULL)
break; /* found it! */
/* out of allocable slots? */
if (i == nexecs) {
error = ENFILE;
break;
}
} else { /* assign */
if (i < 0 || i >= nexecs) {
error = 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));
/* need to recompute max header size */
init_exec();
/* 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(&args->lkm_oldexec, &execsw[i], sizeof(struct execsw));
/* need to recompute max header size */
init_exec();
break;
case LKM_E_STAT: /* no special handling... */
break;
}
return (error);
}
/*
* 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.
*/
int
lkmdispatch(struct lkm_table *lkmtp, int cmd)
{
int error = 0;
#ifdef LKM_DEBUG
printf("lkmdispatch: %x %d\n", lkmtp, cmd);
#endif /* LKM_DEBUG */
switch (lkmtp->private.lkm_any->lkm_type) {
case LM_SYSCALL:
error = _lkm_syscall(lkmtp, cmd);
break;
case LM_VFS:
error = _lkm_vfs(lkmtp, cmd);
break;
case LM_DEV:
error = _lkm_dev(lkmtp, cmd);
break;
case LM_EXEC:
error = _lkm_exec(lkmtp, cmd);
break;
case LM_MISC: /* ignore content -- no "misc-specific" procedure */
break;
default:
error = ENXIO; /* unknown type */
break;
}
return (error);
}