423 lines
8.7 KiB
C
423 lines
8.7 KiB
C
/*-
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* Parts Copyright (c) 1995 Terrence R. Lambert
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* Copyright (c) 1995 Julian R. Elischer
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Terrence R. Lambert.
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* 4. The name Terrence R. Lambert may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
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* 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 TERRENCE R. LAMBERT 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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* $FreeBSD$
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <sys/sysctl.h>
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#include <sys/systm.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/ctype.h>
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#include <machine/stdarg.h>
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#define cdevsw_ALLOCSTART (NUMCDEVSW/2)
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struct cdevsw *cdevsw[NUMCDEVSW];
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static MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
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/*
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* This is the number of hash-buckets. Experiements with 'real-life'
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* udev_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 dev_t's we can create before malloc(9) kick in. */
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#define DEVT_STASH 50
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static struct specinfo devt_stash[DEVT_STASH];
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static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
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static LIST_HEAD(, specinfo) dev_free;
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devfs_create_t *devfs_create_hook;
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devfs_destroy_t *devfs_destroy_hook;
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int devfs_present;
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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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struct cdevsw *
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devsw(dev_t dev)
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{
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if (dev->si_devsw)
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return (dev->si_devsw);
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return(cdevsw[major(dev)]);
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}
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/*
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* Add a cdevsw entry
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*/
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int
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cdevsw_add(struct cdevsw *newentry)
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{
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if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) {
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printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
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newentry->d_name, newentry->d_maj);
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return (EINVAL);
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}
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if (cdevsw[newentry->d_maj]) {
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printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n",
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newentry->d_name, cdevsw[newentry->d_maj]->d_name);
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}
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cdevsw[newentry->d_maj] = newentry;
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return (0);
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}
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/*
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* Remove a cdevsw entry
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*/
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int
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cdevsw_remove(struct cdevsw *oldentry)
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{
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if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) {
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printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n",
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oldentry->d_name, oldentry->d_maj);
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return EINVAL;
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}
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cdevsw[oldentry->d_maj] = NULL;
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return 0;
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}
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/*
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* dev_t and u_dev_t primitives
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*/
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int
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major(dev_t x)
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{
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if (x == NODEV)
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return NOUDEV;
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return((x->si_udev >> 8) & 0xff);
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}
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int
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minor(dev_t x)
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{
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if (x == NODEV)
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return NOUDEV;
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return(x->si_udev & 0xffff00ff);
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}
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int
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dev2unit(dev_t x)
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{
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int i;
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if (x == NODEV)
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return NOUDEV;
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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 dev_t
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allocdev(void)
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{
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static int stashed;
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struct specinfo *si;
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if (stashed >= DEVT_STASH) {
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MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
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M_USE_RESERVE | M_ZERO);
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} else 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 {
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si = devt_stash + stashed++;
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si->si_flags |= SI_STASHED;
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}
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LIST_INIT(&si->si_names);
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TAILQ_INIT(&si->si_snapshots);
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return (si);
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}
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dev_t
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makedev(int x, int y)
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{
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struct specinfo *si;
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udev_t udev;
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int hash;
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if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
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panic("makedev of NOUDEV");
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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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void
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freedev(dev_t dev)
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{
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dev_t adev;
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if (!free_devt)
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return;
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if (SLIST_FIRST(&dev->si_hlist))
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return;
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if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
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return;
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while (!LIST_EMPTY(&dev->si_names)) {
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adev = LIST_FIRST(&dev->si_names);
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adev->si_drv1 = NULL;
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freedev(adev);
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}
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LIST_REMOVE(dev, si_hash);
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if (dev->si_flags & SI_STASHED) {
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bzero(dev, sizeof(*dev));
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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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udev_t
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dev2udev(dev_t x)
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{
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if (x == NODEV)
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return NOUDEV;
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return (x->si_udev);
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}
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dev_t
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udev2dev(udev_t x, int b)
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{
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if (x == NOUDEV)
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return (NODEV);
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switch (b) {
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case 0:
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return makedev(umajor(x), uminor(x));
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case 1:
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return (NODEV);
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default:
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Debugger("udev2dev(...,X)");
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return NODEV;
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}
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}
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int
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uminor(udev_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(udev_t dev)
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{
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return((dev & 0xff00) >> 8);
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}
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udev_t
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makeudev(int x, int y)
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{
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return ((x << 8) | y);
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}
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dev_t
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make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
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{
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dev_t dev;
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va_list ap;
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int i;
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KASSERT(umajor(makeudev(devsw->d_maj, minor)) == devsw->d_maj,
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("Invalid minor (%d) in make_dev", minor));
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dev = makedev(devsw->d_maj, minor);
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if (dev->si_flags & SI_NAMED) {
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printf( "WARNING: Driver mistake: repeat make_dev(\"%s\")\n",
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dev->si_name);
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return (dev);
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}
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va_start(ap, fmt);
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i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
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dev->si_name[i] = '\0';
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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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if (devfs_create_hook)
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devfs_create_hook(dev);
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return (dev);
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}
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dev_t
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make_dev_alias(dev_t pdev, char *fmt, ...)
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{
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dev_t 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->si_flags |= SI_ALIAS;
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dev->si_flags |= SI_NAMED;
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dev->si_drv1 = pdev;
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LIST_INSERT_HEAD(&pdev->si_names, dev, si_hash);
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va_start(ap, fmt);
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i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
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dev->si_name[i] = '\0';
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va_end(ap);
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if (devfs_create_hook)
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devfs_create_hook(dev);
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return (dev);
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}
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void
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destroy_dev(dev_t dev)
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{
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if (!(dev->si_flags & SI_NAMED)) {
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printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
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major(dev), minor(dev));
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return;
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}
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if (devfs_destroy_hook)
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devfs_destroy_hook(dev);
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dev->si_drv1 = 0;
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dev->si_drv2 = 0;
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dev->si_devsw = 0;
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dev->si_flags &= ~SI_NAMED;
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dev->si_flags &= ~SI_ALIAS;
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freedev(dev);
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}
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const char *
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devtoname(dev_t dev)
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{
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char *p;
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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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if (devsw(dev))
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sprintf(p, "#%s/", devsw(dev)->d_name);
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else
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sprintf(p, "#%d/", major(dev));
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p += strlen(p);
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mynor = minor(dev);
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if (mynor < 0 || mynor > 255)
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sprintf(p, "%#x", (u_int)mynor);
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else
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sprintf(p, "%d", mynor);
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}
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return (dev->si_name);
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}
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int
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dev_stdclone(char *name, char **namep, char *stem, int *unit)
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{
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int u, i;
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if (bcmp(stem, name, strlen(stem)) != 0)
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return (0);
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i = strlen(stem);
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if (!isdigit(name[i]))
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return (0);
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u = 0;
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while (isdigit(name[i])) {
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u *= 10;
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u += name[i++] - '0';
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}
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*unit = u;
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if (namep)
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*namep = &name[i];
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if (name[i])
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return (2);
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return (1);
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}
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/*
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* Helper sysctl for devname(3). We're given a {u}dev_t and return
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* the name, if any, registered by the device driver.
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*/
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static int
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sysctl_devname(SYSCTL_HANDLER_ARGS)
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{
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int error;
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udev_t ud;
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dev_t dev;
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error = SYSCTL_IN(req, &ud, sizeof (ud));
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if (error)
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return (error);
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if (ud == NOUDEV)
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return(EINVAL);
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dev = makedev(umajor(ud), uminor(ud));
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if (dev->si_name[0] == '\0')
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error = ENOENT;
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else
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error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
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freedev(dev);
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return (error);
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}
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SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
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NULL, 0, sysctl_devname, "", "devname(3) handler");
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