830 lines
18 KiB
C
830 lines
18 KiB
C
/*-
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* Copyright (c) 1999-2002 Poul-Henning Kamp
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/systm.h>
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#include <sys/bio.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sysctl.h>
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#include <sys/module.h>
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#include <sys/malloc.h>
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#include <sys/conf.h>
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#include <sys/vnode.h>
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#include <sys/queue.h>
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#include <sys/poll.h>
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#include <sys/ctype.h>
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#include <sys/tty.h>
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#include <machine/stdarg.h>
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static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
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/* Built at compile time from sys/conf/majors */
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extern unsigned char reserved_majors[256];
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/*
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* This is the number of hash-buckets. Experiments with 'real-life'
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* dev_t's show that a prime halfway between two powers of two works
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* best.
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*/
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#define DEVT_HASH 83
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/* The number of struct cdev *'s we can create before malloc(9) kick in. */
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#define DEVT_STASH 50
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static struct cdev devt_stash[DEVT_STASH];
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static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
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static LIST_HEAD(, cdev) dev_free;
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static int free_devt;
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SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
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static struct mtx devmtx;
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static void freedev(struct cdev *dev);
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static struct cdev *newdev(int x, int y);
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void
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dev_lock(void)
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{
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if (!mtx_initialized(&devmtx))
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mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
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mtx_lock(&devmtx);
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}
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void
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dev_unlock(void)
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{
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mtx_unlock(&devmtx);
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}
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void
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dev_ref(struct cdev *dev)
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{
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dev_lock();
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dev->si_refcount++;
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dev_unlock();
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}
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void
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dev_rel(struct vnode *vp)
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{
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struct cdev *dev;
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int flag;
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dev = vp->v_rdev;
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mtx_assert(&devmtx, MA_NOTOWNED);
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dev_lock();
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SLIST_REMOVE(&dev->si_hlist, vp, vnode, v_specnext);
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dev->si_usecount -= vp->v_usecount;
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vp->v_rdev = NULL;
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dev->si_refcount--;
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KASSERT(dev->si_refcount >= 0,
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("dev_rel(%s) gave negative count", devtoname(dev)));
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flag = 0;
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if (dev->si_devsw == NULL && dev->si_refcount == 0) {
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LIST_REMOVE(dev, si_list);
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flag = 1;
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}
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dev_unlock();
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if (flag)
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freedev(dev);
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return;
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}
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struct cdevsw *
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dev_refthread(struct cdev *dev)
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{
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struct cdevsw *csw;
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mtx_assert(&devmtx, MA_NOTOWNED);
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dev_lock();
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csw = dev->si_devsw;
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if (csw != NULL)
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dev->si_threadcount++;
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dev_unlock();
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return (csw);
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}
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void
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dev_relthread(struct cdev *dev)
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{
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mtx_assert(&devmtx, MA_NOTOWNED);
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dev_lock();
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dev->si_threadcount--;
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dev_unlock();
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}
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int
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nullop(void)
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{
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return (0);
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}
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int
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eopnotsupp(void)
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{
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return (EOPNOTSUPP);
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}
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static int
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enxio(void)
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{
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return (ENXIO);
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}
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static int
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enodev(void)
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{
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return (ENODEV);
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}
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/* Define a dead_cdevsw for use when devices leave unexpectedly. */
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#define dead_open (d_open_t *)enxio
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#define dead_close (d_close_t *)enxio
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#define dead_read (d_read_t *)enxio
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#define dead_write (d_write_t *)enxio
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#define dead_ioctl (d_ioctl_t *)enxio
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#define dead_poll (d_poll_t *)enodev
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#define dead_mmap (d_mmap_t *)enodev
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static void
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dead_strategy(struct bio *bp)
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{
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biofinish(bp, NULL, ENXIO);
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}
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#define dead_dump (dumper_t *)enxio
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#define dead_kqfilter (d_kqfilter_t *)enxio
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static struct cdevsw dead_cdevsw = {
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.d_version = D_VERSION,
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.d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
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.d_open = dead_open,
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.d_close = dead_close,
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.d_read = dead_read,
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.d_write = dead_write,
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.d_ioctl = dead_ioctl,
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.d_poll = dead_poll,
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.d_mmap = dead_mmap,
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.d_strategy = dead_strategy,
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.d_name = "dead",
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.d_maj = 255,
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.d_dump = dead_dump,
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.d_kqfilter = dead_kqfilter
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};
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/* Default methods if driver does not specify method */
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#define null_open (d_open_t *)nullop
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#define null_close (d_close_t *)nullop
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#define no_read (d_read_t *)enodev
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#define no_write (d_write_t *)enodev
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#define no_ioctl (d_ioctl_t *)enodev
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#define no_mmap (d_mmap_t *)enodev
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#define no_kqfilter (d_kqfilter_t *)enodev
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static void
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no_strategy(struct bio *bp)
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{
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biofinish(bp, NULL, ENODEV);
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}
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static int
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no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
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{
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/*
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* Return true for read/write. If the user asked for something
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* special, return POLLNVAL, so that clients have a way of
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* determining reliably whether or not the extended
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* functionality is present without hard-coding knowledge
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* of specific filesystem implementations.
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* Stay in sync with vop_nopoll().
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*/
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if (events & ~POLLSTANDARD)
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return (POLLNVAL);
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return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
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}
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#define no_dump (dumper_t *)enodev
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/*
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* struct cdev * and u_dev_t primitives
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*/
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int
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major(struct cdev *x)
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{
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if (x == NULL)
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return NODEV;
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return((x->si_udev >> 8) & 0xff);
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}
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int
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minor(struct cdev *x)
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{
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if (x == NULL)
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return NODEV;
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return(x->si_udev & 0xffff00ff);
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}
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int
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dev2unit(struct cdev *x)
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{
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int i;
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if (x == NULL)
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return NODEV;
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i = minor(x);
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return ((i & 0xff) | (i >> 8));
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}
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int
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unit2minor(int unit)
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{
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KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
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return ((unit & 0xff) | ((unit << 8) & ~0xffff));
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}
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static struct cdev *
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allocdev(void)
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{
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static int stashed;
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struct cdev *si;
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if (LIST_FIRST(&dev_free)) {
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si = LIST_FIRST(&dev_free);
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LIST_REMOVE(si, si_hash);
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} else if (stashed >= DEVT_STASH) {
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MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
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M_USE_RESERVE | M_ZERO | M_WAITOK);
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} else {
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si = devt_stash + stashed++;
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bzero(si, sizeof *si);
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si->si_flags |= SI_STASHED;
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}
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si->__si_namebuf[0] = '\0';
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si->si_name = si->__si_namebuf;
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LIST_INIT(&si->si_children);
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return (si);
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}
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static struct cdev *
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newdev(int x, int y)
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{
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struct cdev *si;
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dev_t udev;
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int hash;
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if (x == umajor(NODEV) && y == uminor(NODEV))
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panic("newdev of NODEV");
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udev = (x << 8) | y;
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hash = udev % DEVT_HASH;
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LIST_FOREACH(si, &dev_hash[hash], si_hash) {
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if (si->si_udev == udev)
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return (si);
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}
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si = allocdev();
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si->si_udev = udev;
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LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
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return (si);
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}
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static void
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freedev(struct cdev *dev)
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{
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if (dev->si_flags & SI_STASHED) {
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bzero(dev, sizeof(*dev));
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dev->si_flags |= SI_STASHED;
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LIST_INSERT_HEAD(&dev_free, dev, si_hash);
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} else {
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FREE(dev, M_DEVT);
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}
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}
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dev_t
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dev2udev(struct cdev *x)
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{
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if (x == NULL)
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return (NODEV);
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return (x->si_udev);
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}
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struct cdev *
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findcdev(dev_t udev)
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{
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struct cdev *si;
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int hash;
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if (udev == NODEV)
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return (NULL);
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hash = udev % DEVT_HASH;
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LIST_FOREACH(si, &dev_hash[hash], si_hash) {
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if (si->si_udev == udev)
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return (si);
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}
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return (NULL);
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}
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int
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uminor(dev_t dev)
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{
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return (dev & 0xffff00ff);
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}
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int
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umajor(dev_t dev)
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{
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return ((dev & 0xff00) >> 8);
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}
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static void
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find_major(struct cdevsw *devsw)
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{
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int i;
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for (i = NUMCDEVSW - 1; i > 0; i--)
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if (reserved_majors[i] != i)
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break;
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KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
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devsw->d_maj = i;
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reserved_majors[i] = i;
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devsw->d_flags |= D_ALLOCMAJ;
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}
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static void
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fini_cdevsw(struct cdevsw *devsw)
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{
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if (devsw->d_flags & D_ALLOCMAJ) {
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reserved_majors[devsw->d_maj] = 0;
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devsw->d_maj = MAJOR_AUTO;
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devsw->d_flags &= ~D_ALLOCMAJ;
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} else if (devsw->d_maj == 0)
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devsw->d_maj = 256;
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devsw->d_flags &= ~D_INIT;
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}
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static void
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prep_cdevsw(struct cdevsw *devsw)
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{
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dev_lock();
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if (devsw->d_version != D_VERSION_00) {
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printf(
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"WARNING: Device driver \"%s\" has wrong version %s\n",
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devsw->d_name, "and is disabled. Recompile KLD module.");
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devsw->d_open = dead_open;
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devsw->d_close = dead_close;
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devsw->d_read = dead_read;
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devsw->d_write = dead_write;
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devsw->d_ioctl = dead_ioctl;
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devsw->d_poll = dead_poll;
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devsw->d_mmap = dead_mmap;
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devsw->d_strategy = dead_strategy;
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devsw->d_dump = dead_dump;
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devsw->d_kqfilter = dead_kqfilter;
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}
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if (devsw->d_flags & D_TTY) {
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if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl;
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if (devsw->d_read == NULL) devsw->d_read = ttyread;
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if (devsw->d_write == NULL) devsw->d_write = ttywrite;
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if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter;
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if (devsw->d_poll == NULL) devsw->d_poll = ttypoll;
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}
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if (devsw->d_open == NULL) devsw->d_open = null_open;
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if (devsw->d_close == NULL) devsw->d_close = null_close;
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if (devsw->d_read == NULL) devsw->d_read = no_read;
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if (devsw->d_write == NULL) devsw->d_write = no_write;
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if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl;
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if (devsw->d_poll == NULL) devsw->d_poll = no_poll;
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if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap;
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if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy;
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if (devsw->d_dump == NULL) devsw->d_dump = no_dump;
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if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter;
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LIST_INIT(&devsw->d_devs);
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devsw->d_flags |= D_INIT;
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if (devsw->d_maj == MAJOR_AUTO) {
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find_major(devsw);
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} else {
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if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */
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devsw->d_maj = 0;
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KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
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("Invalid major (%d) in make_dev", devsw->d_maj));
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if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
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printf("WARNING: driver \"%s\" used %s %d\n",
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devsw->d_name, "unreserved major device number",
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devsw->d_maj);
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reserved_majors[devsw->d_maj] = devsw->d_maj;
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}
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}
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dev_unlock();
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}
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struct cdev *
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make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
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{
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struct cdev *dev;
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va_list ap;
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int i;
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KASSERT((minornr & ~0xffff00ff) == 0,
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("Invalid minor (0x%x) in make_dev", minornr));
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if (!(devsw->d_flags & D_INIT))
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prep_cdevsw(devsw);
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dev = newdev(devsw->d_maj, minornr);
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if (dev->si_flags & SI_CHEAPCLONE &&
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dev->si_flags & SI_NAMED &&
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dev->si_devsw == devsw) {
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/*
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* This is allowed as it removes races and generally
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* simplifies cloning devices.
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* XXX: still ??
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*/
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return (dev);
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}
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dev_lock();
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KASSERT(!(dev->si_flags & SI_NAMED),
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("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
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devsw->d_name, major(dev), minor(dev), devtoname(dev)));
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va_start(ap, fmt);
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i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
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if (i > (sizeof dev->__si_namebuf - 1)) {
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printf("WARNING: Device name truncated! (%s)\n",
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dev->__si_namebuf);
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}
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va_end(ap);
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dev->si_devsw = devsw;
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dev->si_uid = uid;
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dev->si_gid = gid;
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dev->si_mode = perms;
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dev->si_flags |= SI_NAMED;
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LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
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devfs_create(dev);
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dev_unlock();
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return (dev);
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}
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int
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dev_named(struct cdev *pdev, const char *name)
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{
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struct cdev *cdev;
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if (strcmp(devtoname(pdev), name) == 0)
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return (1);
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LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
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if (strcmp(devtoname(cdev), name) == 0)
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return (1);
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return (0);
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}
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void
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dev_depends(struct cdev *pdev, struct cdev *cdev)
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{
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|
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dev_lock();
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cdev->si_parent = pdev;
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cdev->si_flags |= SI_CHILD;
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LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
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dev_unlock();
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}
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struct cdev *
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make_dev_alias(struct cdev *pdev, const char *fmt, ...)
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{
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struct cdev *dev;
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va_list ap;
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int i;
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dev = allocdev();
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dev_lock();
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dev->si_flags |= SI_ALIAS;
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dev->si_flags |= SI_NAMED;
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va_start(ap, fmt);
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i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
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if (i > (sizeof dev->__si_namebuf - 1)) {
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printf("WARNING: Device name truncated! (%s)\n",
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dev->__si_namebuf);
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}
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va_end(ap);
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devfs_create(dev);
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dev_unlock();
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dev_depends(pdev, dev);
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return (dev);
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}
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static void
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idestroy_dev(struct cdev *dev)
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{
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struct cdevsw *csw;
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KASSERT(dev->si_flags & SI_NAMED,
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("WARNING: Driver mistake: destroy_dev on %d/%d\n",
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major(dev), minor(dev)));
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devfs_destroy(dev);
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/* Remove name marking */
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dev->si_flags &= ~SI_NAMED;
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/* If we are a child, remove us from the parents list */
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if (dev->si_flags & SI_CHILD) {
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LIST_REMOVE(dev, si_siblings);
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dev->si_flags &= ~SI_CHILD;
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}
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/* Kill our children */
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while (!LIST_EMPTY(&dev->si_children))
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idestroy_dev(LIST_FIRST(&dev->si_children));
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|
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/* Remove from clone list */
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if (dev->si_flags & SI_CLONELIST) {
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LIST_REMOVE(dev, si_clone);
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dev->si_flags &= ~SI_CLONELIST;
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}
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csw = dev->si_devsw;
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dev->si_devsw = NULL; /* already NULL for SI_ALIAS */
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while (csw != NULL && csw->d_purge != NULL && dev->si_threadcount) {
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printf("Purging %lu threads from %s\n",
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dev->si_threadcount, devtoname(dev));
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csw->d_purge(dev);
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msleep(csw, &devmtx, PRIBIO, "devprg", hz/10);
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}
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if (csw != NULL && csw->d_purge != NULL)
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printf("All threads purged from %s\n", devtoname(dev));
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dev->si_drv1 = 0;
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dev->si_drv2 = 0;
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bzero(&dev->__si_u, sizeof(dev->__si_u));
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if (!(dev->si_flags & SI_ALIAS)) {
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/* Remove from cdevsw list */
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LIST_REMOVE(dev, si_list);
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|
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/* If cdevsw has no struct cdev *'s, clean it */
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if (LIST_EMPTY(&csw->d_devs))
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fini_cdevsw(csw);
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LIST_REMOVE(dev, si_hash);
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}
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dev->si_flags &= ~SI_ALIAS;
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|
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if (dev->si_refcount > 0) {
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LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
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} else {
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freedev(dev);
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}
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}
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|
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void
|
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destroy_dev(struct cdev *dev)
|
|
{
|
|
|
|
dev_lock();
|
|
idestroy_dev(dev);
|
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dev_unlock();
|
|
}
|
|
|
|
const char *
|
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devtoname(struct cdev *dev)
|
|
{
|
|
char *p;
|
|
struct cdevsw *csw;
|
|
int mynor;
|
|
|
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if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
|
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p = dev->si_name;
|
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sprintf(p, "#%d", major(dev));
|
|
p += strlen(p);
|
|
csw = dev_refthread(dev);
|
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if (csw != NULL) {
|
|
sprintf(p, "(%s)", csw->d_name);
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dev_relthread(dev);
|
|
}
|
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p += strlen(p);
|
|
mynor = minor(dev);
|
|
if (mynor < 0 || mynor > 255)
|
|
sprintf(p, "/%#x", (u_int)mynor);
|
|
else
|
|
sprintf(p, "/%d", mynor);
|
|
}
|
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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, u_int extra)
|
|
{
|
|
struct clonedevs *cd;
|
|
struct cdev *dev, *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));
|
|
|
|
if (csw->d_maj == MAJOR_AUTO)
|
|
find_major(csw);
|
|
|
|
/*
|
|
* 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;
|
|
low = extra;
|
|
de = dl = NULL;
|
|
cd = *cdp;
|
|
LIST_FOREACH(dev, &cd->head, si_clone) {
|
|
u = dev2unit(dev);
|
|
if (u == (unit | extra)) {
|
|
*dp = dev;
|
|
return (0);
|
|
}
|
|
if (unit == -1 && u == low) {
|
|
low++;
|
|
de = dev;
|
|
continue;
|
|
}
|
|
if (u > (unit | extra)) {
|
|
dl = dev;
|
|
break;
|
|
}
|
|
de = dev;
|
|
}
|
|
if (unit == -1)
|
|
unit = low & CLONE_UNITMASK;
|
|
dev = newdev(csw->d_maj, unit2minor(unit | extra));
|
|
KASSERT(!(dev->si_flags & SI_CLONELIST),
|
|
("Dev %p should not be on clonelist", dev));
|
|
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;
|
|
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, *tdev;
|
|
struct clonedevs *cd;
|
|
|
|
cd = *cdp;
|
|
if (cd == NULL)
|
|
return;
|
|
LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
|
|
KASSERT(dev->si_flags & SI_NAMED,
|
|
("Driver has goofed in cloning underways udev %x", dev->si_udev));
|
|
destroy_dev(dev);
|
|
}
|
|
free(cd, M_DEVBUF);
|
|
*cdp = NULL;
|
|
}
|
|
|
|
/*
|
|
* Helper sysctl for devname(3). We're given a struct cdev * and return
|
|
* the name, if any, registered by the device driver.
|
|
*/
|
|
static int
|
|
sysctl_devname(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
dev_t ud;
|
|
struct cdev *dev;
|
|
|
|
error = SYSCTL_IN(req, &ud, sizeof (ud));
|
|
if (error)
|
|
return (error);
|
|
if (ud == NODEV)
|
|
return(EINVAL);
|
|
dev = findcdev(ud);
|
|
if (dev == NULL)
|
|
error = ENOENT;
|
|
else
|
|
error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
|
|
return (error);
|
|
}
|
|
|
|
SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
|
|
NULL, 0, sysctl_devname, "", "devname(3) handler");
|