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freebsd-dev/sys/kern/kern_conf.c
Hans Petter Selasky 0bad52e1d8 Fix race in devfs by using LIST_FIRST() instead of 
LIST_FOREACH_SAFE() when freeing the devfs private
data entries.

Reviewed by:	kib
MFC after:	3 days
Approved by:	thompsa (mentor)
2010-12-11 08:44:10 +00:00

1361 lines
30 KiB
C
Raw Blame History

/*-
* Copyright (c) 1999-2002 Poul-Henning Kamp
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/bio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/poll.h>
#include <sys/sx.h>
#include <sys/ctype.h>
#include <sys/ucred.h>
#include <sys/taskqueue.h>
#include <machine/stdarg.h>
#include <fs/devfs/devfs_int.h>
#include <vm/vm.h>
static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
struct mtx devmtx;
static void destroy_devl(struct cdev *dev);
static int destroy_dev_sched_cbl(struct cdev *dev,
void (*cb)(void *), void *arg);
static int make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw,
int unit, struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
va_list ap);
static struct cdev_priv_list cdevp_free_list =
TAILQ_HEAD_INITIALIZER(cdevp_free_list);
static SLIST_HEAD(free_cdevsw, cdevsw) cdevsw_gt_post_list =
SLIST_HEAD_INITIALIZER(cdevsw_gt_post_list);
void
dev_lock(void)
{
mtx_lock(&devmtx);
}
/*
* Free all the memory collected while the cdev mutex was
* locked. Since devmtx is after the system map mutex, free() cannot
* be called immediately and is postponed until cdev mutex can be
* dropped.
*/
static void
dev_unlock_and_free(void)
{
struct cdev_priv_list cdp_free;
struct free_cdevsw csw_free;
struct cdev_priv *cdp;
struct cdevsw *csw;
mtx_assert(&devmtx, MA_OWNED);
/*
* Make the local copy of the list heads while the dev_mtx is
* held. Free it later.
*/
TAILQ_INIT(&cdp_free);
TAILQ_CONCAT(&cdp_free, &cdevp_free_list, cdp_list);
csw_free = cdevsw_gt_post_list;
SLIST_INIT(&cdevsw_gt_post_list);
mtx_unlock(&devmtx);
while ((cdp = TAILQ_FIRST(&cdp_free)) != NULL) {
TAILQ_REMOVE(&cdp_free, cdp, cdp_list);
devfs_free(&cdp->cdp_c);
}
while ((csw = SLIST_FIRST(&csw_free)) != NULL) {
SLIST_REMOVE_HEAD(&csw_free, d_postfree_list);
free(csw, M_DEVT);
}
}
static void
dev_free_devlocked(struct cdev *cdev)
{
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_OWNED);
cdp = cdev2priv(cdev);
TAILQ_INSERT_HEAD(&cdevp_free_list, cdp, cdp_list);
}
static void
cdevsw_free_devlocked(struct cdevsw *csw)
{
mtx_assert(&devmtx, MA_OWNED);
SLIST_INSERT_HEAD(&cdevsw_gt_post_list, csw, d_postfree_list);
}
void
dev_unlock(void)
{
mtx_unlock(&devmtx);
}
void
dev_ref(struct cdev *dev)
{
mtx_assert(&devmtx, MA_NOTOWNED);
mtx_lock(&devmtx);
dev->si_refcount++;
mtx_unlock(&devmtx);
}
void
dev_refl(struct cdev *dev)
{
mtx_assert(&devmtx, MA_OWNED);
dev->si_refcount++;
}
void
dev_rel(struct cdev *dev)
{
int flag = 0;
mtx_assert(&devmtx, MA_NOTOWNED);
dev_lock();
dev->si_refcount--;
KASSERT(dev->si_refcount >= 0,
("dev_rel(%s) gave negative count", devtoname(dev)));
#if 0
if (dev->si_usecount == 0 &&
(dev->si_flags & SI_CHEAPCLONE) && (dev->si_flags & SI_NAMED))
;
else
#endif
if (dev->si_devsw == NULL && dev->si_refcount == 0) {
LIST_REMOVE(dev, si_list);
flag = 1;
}
dev_unlock();
if (flag)
devfs_free(dev);
}
struct cdevsw *
dev_refthread(struct cdev *dev, int *ref)
{
struct cdevsw *csw;
struct cdev_priv *cdp;
mtx_assert(&devmtx, MA_NOTOWNED);
if ((dev->si_flags & SI_ETERNAL) != 0) {
*ref = 0;
return (dev->si_devsw);
}
dev_lock();
csw = dev->si_devsw;
if (csw != NULL) {
cdp = cdev2priv(dev);
if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0)
dev->si_threadcount++;
else
csw = NULL;
}
dev_unlock();
*ref = 1;
return (csw);
}
struct cdevsw *
devvn_refthread(struct vnode *vp, struct cdev **devp, int *ref)
{
struct cdevsw *csw;
struct cdev_priv *cdp;
struct cdev *dev;
mtx_assert(&devmtx, MA_NOTOWNED);
if ((vp->v_vflag & VV_ETERNALDEV) != 0) {
dev = vp->v_rdev;
if (dev == NULL)
return (NULL);
KASSERT((dev->si_flags & SI_ETERNAL) != 0,
("Not eternal cdev"));
*ref = 0;
csw = dev->si_devsw;
KASSERT(csw != NULL, ("Eternal cdev is destroyed"));
*devp = dev;
return (csw);
}
csw = NULL;
dev_lock();
dev = vp->v_rdev;
if (dev == NULL) {
dev_unlock();
return (NULL);
}
cdp = cdev2priv(dev);
if ((cdp->cdp_flags & CDP_SCHED_DTR) == 0) {
csw = dev->si_devsw;
if (csw != NULL)
dev->si_threadcount++;
}
dev_unlock();
if (csw != NULL) {
*devp = dev;
*ref = 1;
}
return (csw);
}
void
dev_relthread(struct cdev *dev, int ref)
{
mtx_assert(&devmtx, MA_NOTOWNED);
if (!ref)
return;
dev_lock();
KASSERT(dev->si_threadcount > 0,
("%s threadcount is wrong", dev->si_name));
dev->si_threadcount--;
dev_unlock();
}
int
nullop(void)
{
return (0);
}
int
eopnotsupp(void)
{
return (EOPNOTSUPP);
}
static int
enxio(void)
{
return (ENXIO);
}
static int
enodev(void)
{
return (ENODEV);
}
/* Define a dead_cdevsw for use when devices leave unexpectedly. */
#define dead_open (d_open_t *)enxio
#define dead_close (d_close_t *)enxio
#define dead_read (d_read_t *)enxio
#define dead_write (d_write_t *)enxio
#define dead_ioctl (d_ioctl_t *)enxio
#define dead_poll (d_poll_t *)enodev
#define dead_mmap (d_mmap_t *)enodev
static void
dead_strategy(struct bio *bp)
{
biofinish(bp, NULL, ENXIO);
}
#define dead_dump (dumper_t *)enxio
#define dead_kqfilter (d_kqfilter_t *)enxio
#define dead_mmap_single (d_mmap_single_t *)enodev
static struct cdevsw dead_cdevsw = {
.d_version = D_VERSION,
.d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
.d_open = dead_open,
.d_close = dead_close,
.d_read = dead_read,
.d_write = dead_write,
.d_ioctl = dead_ioctl,
.d_poll = dead_poll,
.d_mmap = dead_mmap,
.d_strategy = dead_strategy,
.d_name = "dead",
.d_dump = dead_dump,
.d_kqfilter = dead_kqfilter,
.d_mmap_single = dead_mmap_single
};
/* Default methods if driver does not specify method */
#define null_open (d_open_t *)nullop
#define null_close (d_close_t *)nullop
#define no_read (d_read_t *)enodev
#define no_write (d_write_t *)enodev
#define no_ioctl (d_ioctl_t *)enodev
#define no_mmap (d_mmap_t *)enodev
#define no_kqfilter (d_kqfilter_t *)enodev
#define no_mmap_single (d_mmap_single_t *)enodev
static void
no_strategy(struct bio *bp)
{
biofinish(bp, NULL, ENODEV);
}
static int
no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
{
return (poll_no_poll(events));
}
#define no_dump (dumper_t *)enodev
static int
giant_open(struct cdev *dev, int oflags, int devtype, struct thread *td)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_open(dev, oflags, devtype, td);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_fdopen(struct cdev *dev, int oflags, struct thread *td, struct file *fp)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_fdopen(dev, oflags, td, fp);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_close(struct cdev *dev, int fflag, int devtype, struct thread *td)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_close(dev, fflag, devtype, td);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static void
giant_strategy(struct bio *bp)
{
struct cdevsw *dsw;
struct cdev *dev;
int ref;
dev = bp->bio_dev;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL) {
biofinish(bp, NULL, ENXIO);
return;
}
mtx_lock(&Giant);
dsw->d_gianttrick->d_strategy(bp);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
}
static int
giant_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_ioctl(dev, cmd, data, fflag, td);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_read(struct cdev *dev, struct uio *uio, int ioflag)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_read(dev, uio, ioflag);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_write(struct cdev *dev, struct uio *uio, int ioflag)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_write(dev, uio, ioflag);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_poll(struct cdev *dev, int events, struct thread *td)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_poll(dev, events, td);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_kqfilter(struct cdev *dev, struct knote *kn)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_kqfilter(dev, kn);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_mmap(struct cdev *dev, vm_ooffset_t offset, vm_paddr_t *paddr, int nprot,
vm_memattr_t *memattr)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_mmap(dev, offset, paddr, nprot,
memattr);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static int
giant_mmap_single(struct cdev *dev, vm_ooffset_t *offset, vm_size_t size,
vm_object_t *object, int nprot)
{
struct cdevsw *dsw;
int ref, retval;
dsw = dev_refthread(dev, &ref);
if (dsw == NULL)
return (ENXIO);
mtx_lock(&Giant);
retval = dsw->d_gianttrick->d_mmap_single(dev, offset, size, object,
nprot);
mtx_unlock(&Giant);
dev_relthread(dev, ref);
return (retval);
}
static void
notify(struct cdev *dev, const char *ev, int flags)
{
static const char prefix[] = "cdev=";
char *data;
int namelen, mflags;
if (cold)
return;
mflags = (flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK;
namelen = strlen(dev->si_name);
data = malloc(namelen + sizeof(prefix), M_TEMP, mflags);
if (data == NULL)
return;
memcpy(data, prefix, sizeof(prefix) - 1);
memcpy(data + sizeof(prefix) - 1, dev->si_name, namelen + 1);
devctl_notify_f("DEVFS", "CDEV", ev, data, mflags);
free(data, M_TEMP);
}
static void
notify_create(struct cdev *dev, int flags)
{
notify(dev, "CREATE", flags);
}
static void
notify_destroy(struct cdev *dev)
{
notify(dev, "DESTROY", MAKEDEV_WAITOK);
}
static struct cdev *
newdev(struct cdevsw *csw, int unit, struct cdev *si)
{
struct cdev *si2;
mtx_assert(&devmtx, MA_OWNED);
if (csw->d_flags & D_NEEDMINOR) {
/* We may want to return an existing device */
LIST_FOREACH(si2, &csw->d_devs, si_list) {
if (dev2unit(si2) == unit) {
dev_free_devlocked(si);
return (si2);
}
}
}
si->si_drv0 = unit;
si->si_devsw = csw;
LIST_INSERT_HEAD(&csw->d_devs, si, si_list);
return (si);
}
static void
fini_cdevsw(struct cdevsw *devsw)
{
struct cdevsw *gt;
if (devsw->d_gianttrick != NULL) {
gt = devsw->d_gianttrick;
memcpy(devsw, gt, sizeof *devsw);
cdevsw_free_devlocked(gt);
devsw->d_gianttrick = NULL;
}
devsw->d_flags &= ~D_INIT;
}
static int
prep_cdevsw(struct cdevsw *devsw, int flags)
{
struct cdevsw *dsw2;
mtx_assert(&devmtx, MA_OWNED);
if (devsw->d_flags & D_INIT)
return (0);
if (devsw->d_flags & D_NEEDGIANT) {
dev_unlock();
dsw2 = malloc(sizeof *dsw2, M_DEVT,
(flags & MAKEDEV_NOWAIT) ? M_NOWAIT : M_WAITOK);
dev_lock();
if (dsw2 == NULL && !(devsw->d_flags & D_INIT))
return (ENOMEM);
} else
dsw2 = NULL;
if (devsw->d_flags & D_INIT) {
if (dsw2 != NULL)
cdevsw_free_devlocked(dsw2);
return (0);
}
if (devsw->d_version != D_VERSION_03) {
printf(
"WARNING: Device driver \"%s\" has wrong version %s\n",
devsw->d_name == NULL ? "???" : devsw->d_name,
"and is disabled. Recompile KLD module.");
devsw->d_open = dead_open;
devsw->d_close = dead_close;
devsw->d_read = dead_read;
devsw->d_write = dead_write;
devsw->d_ioctl = dead_ioctl;
devsw->d_poll = dead_poll;
devsw->d_mmap = dead_mmap;
devsw->d_mmap_single = dead_mmap_single;
devsw->d_strategy = dead_strategy;
devsw->d_dump = dead_dump;
devsw->d_kqfilter = dead_kqfilter;
}
if (devsw->d_flags & D_NEEDGIANT) {
if (devsw->d_gianttrick == NULL) {
memcpy(dsw2, devsw, sizeof *dsw2);
devsw->d_gianttrick = dsw2;
dsw2 = NULL;
}
}
#define FIXUP(member, noop, giant) \
do { \
if (devsw->member == NULL) { \
devsw->member = noop; \
} else if (devsw->d_flags & D_NEEDGIANT) \
devsw->member = giant; \
} \
while (0)
FIXUP(d_open, null_open, giant_open);
FIXUP(d_fdopen, NULL, giant_fdopen);
FIXUP(d_close, null_close, giant_close);
FIXUP(d_read, no_read, giant_read);
FIXUP(d_write, no_write, giant_write);
FIXUP(d_ioctl, no_ioctl, giant_ioctl);
FIXUP(d_poll, no_poll, giant_poll);
FIXUP(d_mmap, no_mmap, giant_mmap);
FIXUP(d_strategy, no_strategy, giant_strategy);
FIXUP(d_kqfilter, no_kqfilter, giant_kqfilter);
FIXUP(d_mmap_single, no_mmap_single, giant_mmap_single);
if (devsw->d_dump == NULL) devsw->d_dump = no_dump;
LIST_INIT(&devsw->d_devs);
devsw->d_flags |= D_INIT;
if (dsw2 != NULL)
cdevsw_free_devlocked(dsw2);
return (0);
}
static int
prep_devname(struct cdev *dev, const char *fmt, va_list ap)
{
int len;
char *from, *q, *s, *to;
mtx_assert(&devmtx, MA_OWNED);
len = vsnrprintf(dev->__si_namebuf, sizeof(dev->__si_namebuf), 32,
fmt, ap);
if (len > sizeof(dev->__si_namebuf) - 1)
return (ENAMETOOLONG);
/* Strip leading slashes. */
for (from = dev->__si_namebuf; *from == '/'; from++)
;
for (to = dev->__si_namebuf; *from != '\0'; from++, to++) {
/* Treat multiple sequential slashes as single. */
while (from[0] == '/' && from[1] == '/')
from++;
/* Trailing slash is considered invalid. */
if (from[0] == '/' && from[1] == '\0')
return (EINVAL);
*to = *from;
}
*to = '\0';
if (dev->__si_namebuf[0] == '\0')
return (EINVAL);
/* Disallow "." and ".." components. */
for (s = dev->__si_namebuf;;) {
for (q = s; *q != '/' && *q != '\0'; q++)
;
if (q - s == 1 && s[0] == '.')
return (EINVAL);
if (q - s == 2 && s[0] == '.' && s[1] == '.')
return (EINVAL);
if (*q != '/')
break;
s = q + 1;
}
if (devfs_dev_exists(dev->__si_namebuf) != 0)
return (EEXIST);
return (0);
}
static int
make_dev_credv(int flags, struct cdev **dres, struct cdevsw *devsw, int unit,
struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt,
va_list ap)
{
struct cdev *dev, *dev_new;
int res;
KASSERT((flags & MAKEDEV_WAITOK) == 0 || (flags & MAKEDEV_NOWAIT) == 0,
("make_dev_credv: both WAITOK and NOWAIT specified"));
dev_new = devfs_alloc(flags);
if (dev_new == NULL)
return (ENOMEM);
dev_lock();
res = prep_cdevsw(devsw, flags);
if (res != 0) {
dev_unlock();
devfs_free(dev_new);
return (res);
}
dev = newdev(devsw, unit, dev_new);
if ((dev->si_flags & SI_NAMED) == 0) {
res = prep_devname(dev, fmt, ap);
if (res != 0) {
if ((flags & MAKEDEV_CHECKNAME) == 0) {
panic(
"make_dev_credv: bad si_name (error=%d, si_name=%s)",
res, dev->si_name);
}
if (dev == dev_new) {
LIST_REMOVE(dev, si_list);
dev_unlock();
devfs_free(dev);
}
return (res);
}
}
if (flags & MAKEDEV_REF)
dev_refl(dev);
if (flags & MAKEDEV_ETERNAL)
dev->si_flags |= SI_ETERNAL;
if (dev->si_flags & SI_CHEAPCLONE &&
dev->si_flags & SI_NAMED) {
/*
* This is allowed as it removes races and generally
* simplifies cloning devices.
* XXX: still ??
*/
dev_unlock_and_free();
*dres = dev;
return (0);
}
KASSERT(!(dev->si_flags & SI_NAMED),
("make_dev() by driver %s on pre-existing device (min=%x, name=%s)",
devsw->d_name, dev2unit(dev), devtoname(dev)));
dev->si_flags |= SI_NAMED;
if (cr != NULL)
dev->si_cred = crhold(cr);
dev->si_uid = uid;
dev->si_gid = gid;
dev->si_mode = mode;
devfs_create(dev);
clean_unrhdrl(devfs_inos);
dev_unlock_and_free();
notify_create(dev, flags);
*dres = dev;
return (0);
}
struct cdev *
make_dev(struct cdevsw *devsw, int unit, uid_t uid, gid_t gid, int mode,
const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int res;
va_start(ap, fmt);
res = make_dev_credv(0, &dev, devsw, unit, NULL, uid, gid, mode, fmt,
ap);
va_end(ap);
KASSERT(res == 0 && dev != NULL,
("make_dev: failed make_dev_credv (error=%d)", res));
return (dev);
}
struct cdev *
make_dev_cred(struct cdevsw *devsw, int unit, struct ucred *cr, uid_t uid,
gid_t gid, int mode, const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int res;
va_start(ap, fmt);
res = make_dev_credv(0, &dev, devsw, unit, cr, uid, gid, mode, fmt, ap);
va_end(ap);
KASSERT(res == 0 && dev != NULL,
("make_dev_cred: failed make_dev_credv (error=%d)", res));
return (dev);
}
struct cdev *
make_dev_credf(int flags, struct cdevsw *devsw, int unit, struct ucred *cr,
uid_t uid, gid_t gid, int mode, const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int res;
va_start(ap, fmt);
res = make_dev_credv(flags, &dev, devsw, unit, cr, uid, gid, mode,
fmt, ap);
va_end(ap);
KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
("make_dev_credf: failed make_dev_credv (error=%d)", res));
return (res == 0 ? dev : NULL);
}
int
make_dev_p(int flags, struct cdev **cdev, struct cdevsw *devsw,
struct ucred *cr, uid_t uid, gid_t gid, int mode, const char *fmt, ...)
{
va_list ap;
int res;
va_start(ap, fmt);
res = make_dev_credv(flags, cdev, devsw, 0, cr, uid, gid, mode,
fmt, ap);
va_end(ap);
KASSERT(((flags & MAKEDEV_NOWAIT) != 0 && res == ENOMEM) ||
((flags & MAKEDEV_CHECKNAME) != 0 && res != ENOMEM) || res == 0,
("make_dev_p: failed make_dev_credv (error=%d)", res));
return (res);
}
static void
dev_dependsl(struct cdev *pdev, struct cdev *cdev)
{
cdev->si_parent = pdev;
cdev->si_flags |= SI_CHILD;
LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
}
void
dev_depends(struct cdev *pdev, struct cdev *cdev)
{
dev_lock();
dev_dependsl(pdev, cdev);
dev_unlock();
}
struct cdev *
make_dev_alias(struct cdev *pdev, const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int error;
KASSERT(pdev != NULL, ("NULL pdev"));
dev = devfs_alloc(MAKEDEV_WAITOK);
dev_lock();
dev->si_flags |= SI_ALIAS;
va_start(ap, fmt);
error = prep_devname(dev, fmt, ap);
va_end(ap);
if (error != 0) {
panic("make_dev_alias: bad si_name (error=%d, si_name=%s)",
error, dev->si_name);
}
dev->si_flags |= SI_NAMED;
devfs_create(dev);
dev_dependsl(pdev, dev);
clean_unrhdrl(devfs_inos);
dev_unlock();
notify_create(dev, MAKEDEV_WAITOK);
return (dev);
}
static void
destroy_devl(struct cdev *dev)
{
struct cdevsw *csw;
struct cdev_privdata *p;
mtx_assert(&devmtx, MA_OWNED);
KASSERT(dev->si_flags & SI_NAMED,
("WARNING: Driver mistake: destroy_dev on %d\n", dev2unit(dev)));
KASSERT((dev->si_flags & SI_ETERNAL) == 0,
("WARNING: Driver mistake: destroy_dev on eternal %d\n",
dev2unit(dev)));
devfs_destroy(dev);
/* Remove name marking */
dev->si_flags &= ~SI_NAMED;
/* If we are a child, remove us from the parents list */
if (dev->si_flags & SI_CHILD) {
LIST_REMOVE(dev, si_siblings);
dev->si_flags &= ~SI_CHILD;
}
/* Kill our children */
while (!LIST_EMPTY(&dev->si_children))
destroy_devl(LIST_FIRST(&dev->si_children));
/* Remove from clone list */
if (dev->si_flags & SI_CLONELIST) {
LIST_REMOVE(dev, si_clone);
dev->si_flags &= ~SI_CLONELIST;
}
dev->si_refcount++; /* Avoid race with dev_rel() */
csw = dev->si_devsw;
dev->si_devsw = NULL; /* already NULL for SI_ALIAS */
while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
csw->d_purge(dev);
msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
if (dev->si_threadcount)
printf("Still %lu threads in %s\n",
dev->si_threadcount, devtoname(dev));
}
while (dev->si_threadcount != 0) {
/* Use unique dummy wait ident */
msleep(&csw, &devmtx, PRIBIO, "devdrn", hz / 10);
}
dev_unlock();
notify_destroy(dev);
mtx_lock(&cdevpriv_mtx);
while ((p = LIST_FIRST(&cdev2priv(dev)->cdp_fdpriv)) != NULL) {
devfs_destroy_cdevpriv(p);
mtx_lock(&cdevpriv_mtx);
}
mtx_unlock(&cdevpriv_mtx);
dev_lock();
dev->si_drv1 = 0;
dev->si_drv2 = 0;
bzero(&dev->__si_u, sizeof(dev->__si_u));
if (!(dev->si_flags & SI_ALIAS)) {
/* Remove from cdevsw list */
LIST_REMOVE(dev, si_list);
/* If cdevsw has no more struct cdev *'s, clean it */
if (LIST_EMPTY(&csw->d_devs)) {
fini_cdevsw(csw);
wakeup(&csw->d_devs);
}
}
dev->si_flags &= ~SI_ALIAS;
dev->si_refcount--; /* Avoid race with dev_rel() */
if (dev->si_refcount > 0) {
LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
} else {
dev_free_devlocked(dev);
}
}
void
destroy_dev(struct cdev *dev)
{
WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL, "destroy_dev");
dev_lock();
destroy_devl(dev);
dev_unlock_and_free();
}
const char *
devtoname(struct cdev *dev)
{
return (dev->si_name);
}
int
dev_stdclone(char *name, char **namep, const char *stem, int *unit)
{
int u, i;
i = strlen(stem);
if (bcmp(stem, name, i) != 0)
return (0);
if (!isdigit(name[i]))
return (0);
u = 0;
if (name[i] == '0' && isdigit(name[i+1]))
return (0);
while (isdigit(name[i])) {
u *= 10;
u += name[i++] - '0';
}
if (u > 0xffffff)
return (0);
*unit = u;
if (namep)
*namep = &name[i];
if (name[i])
return (2);
return (1);
}
/*
* Helper functions for cloning device drivers.
*
* The objective here is to make it unnecessary for the device drivers to
* use rman or similar to manage their unit number space. Due to the way
* we do "on-demand" devices, using rman or other "private" methods
* will be very tricky to lock down properly once we lock down this file.
*
* Instead we give the drivers these routines which puts the struct cdev *'s
* that are to be managed on their own list, and gives the driver the ability
* to ask for the first free unit number or a given specified unit number.
*
* In addition these routines support paired devices (pty, nmdm and similar)
* by respecting a number of "flag" bits in the minor number.
*
*/
struct clonedevs {
LIST_HEAD(,cdev) head;
};
void
clone_setup(struct clonedevs **cdp)
{
*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
LIST_INIT(&(*cdp)->head);
}
int
clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up,
struct cdev **dp, int extra)
{
struct clonedevs *cd;
struct cdev *dev, *ndev, *dl, *de;
int unit, low, u;
KASSERT(*cdp != NULL,
("clone_setup() not called in driver \"%s\"", csw->d_name));
KASSERT(!(extra & CLONE_UNITMASK),
("Illegal extra bits (0x%x) in clone_create", extra));
KASSERT(*up <= CLONE_UNITMASK,
("Too high unit (0x%x) in clone_create", *up));
KASSERT(csw->d_flags & D_NEEDMINOR,
("clone_create() on cdevsw without minor numbers"));
/*
* Search the list for a lot of things in one go:
* A preexisting match is returned immediately.
* The lowest free unit number if we are passed -1, and the place
* in the list where we should insert that new element.
* The place to insert a specified unit number, if applicable
* the end of the list.
*/
unit = *up;
ndev = devfs_alloc(MAKEDEV_WAITOK);
dev_lock();
prep_cdevsw(csw, MAKEDEV_WAITOK);
low = extra;
de = dl = NULL;
cd = *cdp;
LIST_FOREACH(dev, &cd->head, si_clone) {
KASSERT(dev->si_flags & SI_CLONELIST,
("Dev %p(%s) should be on clonelist", dev, dev->si_name));
u = dev2unit(dev);
if (u == (unit | extra)) {
*dp = dev;
dev_unlock();
devfs_free(ndev);
return (0);
}
if (unit == -1 && u == low) {
low++;
de = dev;
continue;
} else if (u < (unit | extra)) {
de = dev;
continue;
} else if (u > (unit | extra)) {
dl = dev;
break;
}
}
if (unit == -1)
unit = low & CLONE_UNITMASK;
dev = newdev(csw, unit | extra, ndev);
if (dev->si_flags & SI_CLONELIST) {
printf("dev %p (%s) is on clonelist\n", dev, dev->si_name);
printf("unit=%d, low=%d, extra=0x%x\n", unit, low, extra);
LIST_FOREACH(dev, &cd->head, si_clone) {
printf("\t%p %s\n", dev, dev->si_name);
}
panic("foo");
}
KASSERT(!(dev->si_flags & SI_CLONELIST),
("Dev %p(%s) should not be on clonelist", dev, dev->si_name));
if (dl != NULL)
LIST_INSERT_BEFORE(dl, dev, si_clone);
else if (de != NULL)
LIST_INSERT_AFTER(de, dev, si_clone);
else
LIST_INSERT_HEAD(&cd->head, dev, si_clone);
dev->si_flags |= SI_CLONELIST;
*up = unit;
dev_unlock_and_free();
return (1);
}
/*
* Kill everything still on the list. The driver should already have
* disposed of any softc hung of the struct cdev *'s at this time.
*/
void
clone_cleanup(struct clonedevs **cdp)
{
struct cdev *dev;
struct cdev_priv *cp;
struct clonedevs *cd;
cd = *cdp;
if (cd == NULL)
return;
dev_lock();
while (!LIST_EMPTY(&cd->head)) {
dev = LIST_FIRST(&cd->head);
LIST_REMOVE(dev, si_clone);
KASSERT(dev->si_flags & SI_CLONELIST,
("Dev %p(%s) should be on clonelist", dev, dev->si_name));
dev->si_flags &= ~SI_CLONELIST;
cp = cdev2priv(dev);
if (!(cp->cdp_flags & CDP_SCHED_DTR)) {
cp->cdp_flags |= CDP_SCHED_DTR;
KASSERT(dev->si_flags & SI_NAMED,
("Driver has goofed in cloning underways udev %x unit %x", dev2udev(dev), dev2unit(dev)));
destroy_devl(dev);
}
}
dev_unlock_and_free();
free(cd, M_DEVBUF);
*cdp = NULL;
}
static TAILQ_HEAD(, cdev_priv) dev_ddtr =
TAILQ_HEAD_INITIALIZER(dev_ddtr);
static struct task dev_dtr_task;
static void
destroy_dev_tq(void *ctx, int pending)
{
struct cdev_priv *cp;
struct cdev *dev;
void (*cb)(void *);
void *cb_arg;
dev_lock();
while (!TAILQ_EMPTY(&dev_ddtr)) {
cp = TAILQ_FIRST(&dev_ddtr);
dev = &cp->cdp_c;
KASSERT(cp->cdp_flags & CDP_SCHED_DTR,
("cdev %p in dev_destroy_tq without CDP_SCHED_DTR", cp));
TAILQ_REMOVE(&dev_ddtr, cp, cdp_dtr_list);
cb = cp->cdp_dtr_cb;
cb_arg = cp->cdp_dtr_cb_arg;
destroy_devl(dev);
dev_unlock_and_free();
dev_rel(dev);
if (cb != NULL)
cb(cb_arg);
dev_lock();
}
dev_unlock();
}
/*
* devmtx shall be locked on entry. devmtx will be unlocked after
* function return.
*/
static int
destroy_dev_sched_cbl(struct cdev *dev, void (*cb)(void *), void *arg)
{
struct cdev_priv *cp;
mtx_assert(&devmtx, MA_OWNED);
cp = cdev2priv(dev);
if (cp->cdp_flags & CDP_SCHED_DTR) {
dev_unlock();
return (0);
}
dev_refl(dev);
cp->cdp_flags |= CDP_SCHED_DTR;
cp->cdp_dtr_cb = cb;
cp->cdp_dtr_cb_arg = arg;
TAILQ_INSERT_TAIL(&dev_ddtr, cp, cdp_dtr_list);
dev_unlock();
taskqueue_enqueue(taskqueue_swi_giant, &dev_dtr_task);
return (1);
}
int
destroy_dev_sched_cb(struct cdev *dev, void (*cb)(void *), void *arg)
{
dev_lock();
return (destroy_dev_sched_cbl(dev, cb, arg));
}
int
destroy_dev_sched(struct cdev *dev)
{
return (destroy_dev_sched_cb(dev, NULL, NULL));
}
void
destroy_dev_drain(struct cdevsw *csw)
{
dev_lock();
while (!LIST_EMPTY(&csw->d_devs)) {
msleep(&csw->d_devs, &devmtx, PRIBIO, "devscd", hz/10);
}
dev_unlock();
}
void
drain_dev_clone_events(void)
{
sx_xlock(&clone_drain_lock);
sx_xunlock(&clone_drain_lock);
}
static void
devdtr_init(void *dummy __unused)
{
TASK_INIT(&dev_dtr_task, 0, destroy_dev_tq, NULL);
}
SYSINIT(devdtr, SI_SUB_DEVFS, SI_ORDER_SECOND, devdtr_init, NULL);
#include "opt_ddb.h"
#ifdef DDB
#include <sys/kernel.h>
#include <ddb/ddb.h>
DB_SHOW_COMMAND(cdev, db_show_cdev)
{
struct cdev_priv *cdp;
struct cdev *dev;
u_int flags;
char buf[512];
if (!have_addr) {
TAILQ_FOREACH(cdp, &cdevp_list, cdp_list) {
dev = &cdp->cdp_c;
db_printf("%s %p\n", dev->si_name, dev);
if (db_pager_quit)
break;
}
return;
}
dev = (struct cdev *)addr;
cdp = cdev2priv(dev);
db_printf("dev %s ref %d use %ld thr %ld inuse %u fdpriv %p\n",
dev->si_name, dev->si_refcount, dev->si_usecount,
dev->si_threadcount, cdp->cdp_inuse, cdp->cdp_fdpriv.lh_first);
db_printf("devsw %p si_drv0 %d si_drv1 %p si_drv2 %p\n",
dev->si_devsw, dev->si_drv0, dev->si_drv1, dev->si_drv2);
flags = dev->si_flags;
#define SI_FLAG(flag) do { \
if (flags & (flag)) { \
if (buf[0] != '\0') \
strlcat(buf, ", ", sizeof(buf)); \
strlcat(buf, (#flag) + 3, sizeof(buf)); \
flags &= ~(flag); \
} \
} while (0)
buf[0] = '\0';
SI_FLAG(SI_ETERNAL);
SI_FLAG(SI_ALIAS);
SI_FLAG(SI_NAMED);
SI_FLAG(SI_CHEAPCLONE);
SI_FLAG(SI_CHILD);
SI_FLAG(SI_DEVOPEN);
SI_FLAG(SI_CONSOPEN);
SI_FLAG(SI_DUMPDEV);
SI_FLAG(SI_CANDELETE);
SI_FLAG(SI_CLONELIST);
db_printf("si_flags %s\n", buf);
flags = cdp->cdp_flags;
#define CDP_FLAG(flag) do { \
if (flags & (flag)) { \
if (buf[0] != '\0') \
strlcat(buf, ", ", sizeof(buf)); \
strlcat(buf, (#flag) + 4, sizeof(buf)); \
flags &= ~(flag); \
} \
} while (0)
buf[0] = '\0';
CDP_FLAG(CDP_ACTIVE);
CDP_FLAG(CDP_SCHED_DTR);
db_printf("cdp_flags %s\n", buf);
}
#endif
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