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67673e6677
and the previously malloc'ed snapshot lock. Malloc struct snapdata instead of just the lock. Replace snapshot fields in cdev with pointer to snapdata (saves 16 bytes). While here, give the private readblock() function a vnode argument in preparation for moving UFS to access GEOM directly.
802 lines
18 KiB
C
802 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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static void
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devlock(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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static void
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devunlock(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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devlock();
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dev->si_refcount++;
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devunlock();
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}
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void
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dev_rel(struct cdev *dev)
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{
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devlock();
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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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if (dev->si_devsw == NULL && dev->si_refcount == 0) {
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LIST_REMOVE(dev, si_list);
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freedev(dev);
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}
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devunlock();
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}
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void
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cdevsw_ref(struct cdevsw *csw)
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{
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devlock();
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csw->d_refcount++;
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devunlock();
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}
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void
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cdevsw_rel(struct cdevsw *csw)
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{
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devlock();
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csw->d_refcount--;
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KASSERT(csw->d_refcount >= 0,
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("cdevsw_vrel(%s) gave negative count", csw->d_name));
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devunlock();
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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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struct cdevsw *
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devsw(struct cdev *dev)
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{
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if (dev->si_devsw != NULL)
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return (dev->si_devsw);
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return (&dead_cdevsw);
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}
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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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devlock();
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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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devunlock();
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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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devlock();
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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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devunlock();
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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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devlock();
|
|
cdev->si_parent = pdev;
|
|
cdev->si_flags |= SI_CHILD;
|
|
LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
|
|
devunlock();
|
|
}
|
|
|
|
struct cdev *
|
|
make_dev_alias(struct cdev *pdev, const char *fmt, ...)
|
|
{
|
|
struct cdev *dev;
|
|
va_list ap;
|
|
int i;
|
|
|
|
dev = allocdev();
|
|
devlock();
|
|
dev->si_flags |= SI_ALIAS;
|
|
dev->si_flags |= SI_NAMED;
|
|
va_start(ap, fmt);
|
|
i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
|
|
if (i > (sizeof dev->__si_namebuf - 1)) {
|
|
printf("WARNING: Device name truncated! (%s)\n",
|
|
dev->__si_namebuf);
|
|
}
|
|
va_end(ap);
|
|
|
|
devfs_create(dev);
|
|
devunlock();
|
|
dev_depends(pdev, dev);
|
|
return (dev);
|
|
}
|
|
|
|
static void
|
|
idestroy_dev(struct cdev *dev)
|
|
{
|
|
if (!(dev->si_flags & SI_NAMED)) {
|
|
printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
|
|
major(dev), minor(dev));
|
|
panic("don't do that");
|
|
}
|
|
|
|
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))
|
|
idestroy_dev(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;
|
|
}
|
|
|
|
if (!(dev->si_flags & SI_ALIAS)) {
|
|
/* Remove from cdevsw list */
|
|
LIST_REMOVE(dev, si_list);
|
|
|
|
/* If cdevsw has no struct cdev *'s, clean it */
|
|
if (LIST_EMPTY(&dev->si_devsw->d_devs))
|
|
fini_cdevsw(dev->si_devsw);
|
|
|
|
LIST_REMOVE(dev, si_hash);
|
|
}
|
|
dev->si_drv1 = 0;
|
|
dev->si_drv2 = 0;
|
|
dev->si_devsw = NULL;
|
|
bzero(&dev->__si_u, sizeof(dev->__si_u));
|
|
dev->si_flags &= ~SI_ALIAS;
|
|
if (dev->si_refcount > 0) {
|
|
LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
|
|
} else {
|
|
freedev(dev);
|
|
}
|
|
}
|
|
|
|
void
|
|
destroy_dev(struct cdev *dev)
|
|
{
|
|
|
|
devlock();
|
|
idestroy_dev(dev);
|
|
devunlock();
|
|
}
|
|
|
|
const char *
|
|
devtoname(struct cdev *dev)
|
|
{
|
|
char *p;
|
|
int mynor;
|
|
|
|
if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
|
|
p = dev->si_name;
|
|
if (devsw(dev))
|
|
sprintf(p, "#%s/", devsw(dev)->d_name);
|
|
else
|
|
sprintf(p, "#%d/", major(dev));
|
|
p += strlen(p);
|
|
mynor = minor(dev);
|
|
if (mynor < 0 || mynor > 255)
|
|
sprintf(p, "%#x", (u_int)mynor);
|
|
else
|
|
sprintf(p, "%d", mynor);
|
|
}
|
|
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");
|