f30a88f9b1
The nmdm code enforces a number between the 'nmdm' and 'A|B' portions of the device name. This is then used as a unit number, and sprintf'd back into the tty name. If leading zeros were used in the name, the created device name is different than the string used for the clone-open (e.g. /dev/nmdm0001A will result in /dev/nmdm1A). Since unit numbers are no longer required with the updated tty code, there seems to be no reason to force the string to be a number. The fix is to allow an arbitrary string between 'nmdm' and 'A|B', within the constraints of devfs names. This allows all existing user of numeric strings to continue to work, and also allows more meaningful names to be used, such as bhyve VM names. Tested on amd64, i386 and ppc64. Reported by: Dave Smith PR: 192281 Reviewed by: neel, glebius Phabric: D729 MFC after: 3 days
450 lines
10 KiB
C
450 lines
10 KiB
C
/*-
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* Copyright (c) 1982, 1986, 1989, 1993
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* The Regents of the University of California. 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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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* Pseudo-nulmodem driver
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* Mighty handy for use with serial console in Vmware
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*/
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/tty.h>
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#include <sys/conf.h>
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#include <sys/fcntl.h>
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#include <sys/poll.h>
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#include <sys/kernel.h>
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#include <sys/limits.h>
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#include <sys/module.h>
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#include <sys/serial.h>
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#include <sys/signalvar.h>
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#include <sys/malloc.h>
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#include <sys/taskqueue.h>
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static MALLOC_DEFINE(M_NMDM, "nullmodem", "nullmodem data structures");
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static tsw_inwakeup_t nmdm_outwakeup;
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static tsw_outwakeup_t nmdm_inwakeup;
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static tsw_param_t nmdm_param;
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static tsw_modem_t nmdm_modem;
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static tsw_close_t nmdm_close;
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static tsw_free_t nmdm_free;
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static struct ttydevsw nmdm_class = {
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.tsw_flags = TF_NOPREFIX,
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.tsw_inwakeup = nmdm_inwakeup,
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.tsw_outwakeup = nmdm_outwakeup,
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.tsw_param = nmdm_param,
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.tsw_modem = nmdm_modem,
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.tsw_close = nmdm_close,
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.tsw_free = nmdm_free,
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};
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static void nmdm_task_tty(void *, int);
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struct nmdmsoftc;
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struct nmdmpart {
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struct tty *np_tty;
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int np_dcd;
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struct task np_task;
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struct nmdmpart *np_other;
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struct nmdmsoftc *np_pair;
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struct callout np_callout;
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u_long np_quota;
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u_long np_accumulator;
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int np_rate;
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int np_credits;
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#define QS 8 /* Quota shift */
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};
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struct nmdmsoftc {
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struct nmdmpart ns_part1;
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struct nmdmpart ns_part2;
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struct mtx ns_mtx;
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};
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static int nmdm_count = 0;
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static void
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nmdm_close(struct tty *tp)
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{
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struct nmdmpart *np;
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struct nmdmpart *onp;
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struct tty *otp;
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np = tty_softc(tp);
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onp = np->np_other;
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otp = onp->np_tty;
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/* If second part is opened, do not destroy ourselves. */
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if (tty_opened(otp))
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return;
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/* Shut down self. */
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tty_rel_gone(tp);
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/* Shut down second part. */
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tty_lock(tp);
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onp = np->np_other;
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if (onp == NULL)
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return;
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otp = onp->np_tty;
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tty_rel_gone(otp);
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tty_lock(tp);
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}
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static void
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nmdm_free(void *softc)
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{
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struct nmdmpart *np = (struct nmdmpart *)softc;
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struct nmdmsoftc *ns = np->np_pair;
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callout_drain(&np->np_callout);
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taskqueue_drain(taskqueue_swi, &np->np_task);
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/*
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* The function is called on both parts simultaneously. We serialize
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* with help of ns_mtx. The first invocation should return and
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* delegate freeing of resources to the second.
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*/
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mtx_lock(&ns->ns_mtx);
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if (np->np_other != NULL) {
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np->np_other->np_other = NULL;
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mtx_unlock(&ns->ns_mtx);
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return;
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}
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mtx_destroy(&ns->ns_mtx);
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free(ns, M_NMDM);
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atomic_subtract_int(&nmdm_count, 1);
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}
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static void
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nmdm_clone(void *arg, struct ucred *cred, char *name, int nameen,
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struct cdev **dev)
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{
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struct nmdmsoftc *ns;
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struct tty *tp;
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char *end;
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int error;
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char endc;
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if (*dev != NULL)
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return;
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if (strncmp(name, "nmdm", 4) != 0)
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return;
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if (strlen(name) <= strlen("nmdmX"))
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return;
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/* Device name must be "nmdm%s%c", where %c is 'A' or 'B'. */
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end = name + strlen(name) - 1;
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endc = *end;
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if (endc != 'A' && endc != 'B')
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return;
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ns = malloc(sizeof(*ns), M_NMDM, M_WAITOK | M_ZERO);
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mtx_init(&ns->ns_mtx, "nmdm", NULL, MTX_DEF);
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/* Hook the pairs together. */
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ns->ns_part1.np_pair = ns;
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ns->ns_part1.np_other = &ns->ns_part2;
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TASK_INIT(&ns->ns_part1.np_task, 0, nmdm_task_tty, &ns->ns_part1);
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callout_init_mtx(&ns->ns_part1.np_callout, &ns->ns_mtx, 0);
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ns->ns_part2.np_pair = ns;
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ns->ns_part2.np_other = &ns->ns_part1;
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TASK_INIT(&ns->ns_part2.np_task, 0, nmdm_task_tty, &ns->ns_part2);
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callout_init_mtx(&ns->ns_part2.np_callout, &ns->ns_mtx, 0);
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/* Create device nodes. */
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tp = ns->ns_part1.np_tty = tty_alloc_mutex(&nmdm_class, &ns->ns_part1,
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&ns->ns_mtx);
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*end = 'A';
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error = tty_makedevf(tp, NULL, endc == 'A' ? TTYMK_CLONING : 0,
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"%s", name);
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if (error) {
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*end = endc;
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mtx_destroy(&ns->ns_mtx);
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free(ns, M_NMDM);
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return;
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}
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tp = ns->ns_part2.np_tty = tty_alloc_mutex(&nmdm_class, &ns->ns_part2,
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&ns->ns_mtx);
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*end = 'B';
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error = tty_makedevf(tp, NULL, endc == 'B' ? TTYMK_CLONING : 0,
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"%s", name);
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if (error) {
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*end = endc;
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mtx_lock(&ns->ns_mtx);
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/* see nmdm_free() */
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ns->ns_part1.np_other = NULL;
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atomic_add_int(&nmdm_count, 1);
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tty_rel_gone(ns->ns_part1.np_tty);
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return;
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}
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if (endc == 'A')
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*dev = ns->ns_part1.np_tty->t_dev;
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else
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*dev = ns->ns_part2.np_tty->t_dev;
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*end = endc;
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atomic_add_int(&nmdm_count, 1);
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}
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static void
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nmdm_timeout(void *arg)
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{
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struct nmdmpart *np = arg;
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if (np->np_rate == 0)
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return;
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/*
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* Do a simple Floyd-Steinberg dither here to avoid FP math.
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* Wipe out unused quota from last tick.
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*/
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np->np_accumulator += np->np_credits;
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np->np_quota = np->np_accumulator >> QS;
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np->np_accumulator &= ((1 << QS) - 1);
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taskqueue_enqueue(taskqueue_swi, &np->np_task);
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callout_reset(&np->np_callout, np->np_rate, nmdm_timeout, np);
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}
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static void
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nmdm_task_tty(void *arg, int pending __unused)
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{
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struct tty *tp, *otp;
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struct nmdmpart *np = arg;
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char c;
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tp = np->np_tty;
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tty_lock(tp);
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if (tty_gone(tp)) {
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tty_unlock(tp);
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return;
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}
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otp = np->np_other->np_tty;
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KASSERT(otp != NULL, ("NULL otp in nmdmstart"));
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KASSERT(otp != tp, ("NULL otp == tp nmdmstart"));
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if (np->np_other->np_dcd) {
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if (!tty_opened(tp)) {
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np->np_other->np_dcd = 0;
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ttydisc_modem(otp, 0);
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}
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} else {
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if (tty_opened(tp)) {
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np->np_other->np_dcd = 1;
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ttydisc_modem(otp, 1);
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}
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}
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/* This may happen when we are in detach process. */
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if (tty_gone(otp)) {
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tty_unlock(otp);
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return;
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}
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while (ttydisc_rint_poll(otp) > 0) {
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if (np->np_rate && !np->np_quota)
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break;
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if (ttydisc_getc(tp, &c, 1) != 1)
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break;
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np->np_quota--;
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ttydisc_rint(otp, c, 0);
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}
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ttydisc_rint_done(otp);
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tty_unlock(tp);
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}
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static int
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bits_per_char(struct termios *t)
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{
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int bits;
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bits = 1; /* start bit */
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switch (t->c_cflag & CSIZE) {
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case CS5: bits += 5; break;
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case CS6: bits += 6; break;
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case CS7: bits += 7; break;
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case CS8: bits += 8; break;
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}
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bits++; /* stop bit */
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if (t->c_cflag & PARENB)
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bits++;
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if (t->c_cflag & CSTOPB)
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bits++;
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return (bits);
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}
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static int
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nmdm_param(struct tty *tp, struct termios *t)
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{
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struct nmdmpart *np = tty_softc(tp);
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struct tty *tp2;
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int bpc, rate, speed, i;
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tp2 = np->np_other->np_tty;
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if (!((t->c_cflag | tp2->t_termios.c_cflag) & CDSR_OFLOW)) {
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np->np_rate = 0;
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np->np_other->np_rate = 0;
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return (0);
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}
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/*
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* DSRFLOW one either side enables rate-simulation for both
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* directions.
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* NB: the two directions may run at different rates.
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*/
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/* Find the larger of the number of bits transmitted */
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bpc = imax(bits_per_char(t), bits_per_char(&tp2->t_termios));
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for (i = 0; i < 2; i++) {
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/* Use the slower of our receive and their transmit rate */
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speed = imin(tp2->t_termios.c_ospeed, t->c_ispeed);
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if (speed == 0) {
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np->np_rate = 0;
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np->np_other->np_rate = 0;
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return (0);
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}
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speed <<= QS; /* [bit/sec, scaled] */
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speed /= bpc; /* [char/sec, scaled] */
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rate = (hz << QS) / speed; /* [hz per callout] */
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if (rate == 0)
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rate = 1;
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speed *= rate;
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speed /= hz; /* [(char/sec)/tick, scaled */
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np->np_credits = speed;
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np->np_rate = rate;
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callout_reset(&np->np_callout, rate, nmdm_timeout, np);
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/*
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* swap pointers for second pass so the other end gets
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* updated as well.
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*/
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np = np->np_other;
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t = &tp2->t_termios;
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tp2 = tp;
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}
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return (0);
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}
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static int
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nmdm_modem(struct tty *tp, int sigon, int sigoff)
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{
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struct nmdmpart *np = tty_softc(tp);
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int i = 0;
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if (sigon || sigoff) {
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if (sigon & SER_DTR)
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np->np_other->np_dcd = 1;
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if (sigoff & SER_DTR)
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np->np_other->np_dcd = 0;
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ttydisc_modem(np->np_other->np_tty, np->np_other->np_dcd);
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return (0);
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} else {
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if (np->np_dcd)
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i |= SER_DCD;
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if (np->np_other->np_dcd)
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i |= SER_DTR;
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return (i);
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}
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}
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static void
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nmdm_inwakeup(struct tty *tp)
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{
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struct nmdmpart *np = tty_softc(tp);
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/* We can receive again, so wake up the other side. */
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taskqueue_enqueue(taskqueue_swi, &np->np_other->np_task);
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}
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static void
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nmdm_outwakeup(struct tty *tp)
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{
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struct nmdmpart *np = tty_softc(tp);
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/* We can transmit again, so wake up our side. */
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taskqueue_enqueue(taskqueue_swi, &np->np_task);
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}
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/*
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* Module handling
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*/
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static int
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nmdm_modevent(module_t mod, int type, void *data)
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{
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static eventhandler_tag tag;
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switch(type) {
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case MOD_LOAD:
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tag = EVENTHANDLER_REGISTER(dev_clone, nmdm_clone, 0, 1000);
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if (tag == NULL)
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return (ENOMEM);
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break;
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case MOD_SHUTDOWN:
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break;
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case MOD_UNLOAD:
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if (nmdm_count != 0)
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return (EBUSY);
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EVENTHANDLER_DEREGISTER(dev_clone, tag);
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break;
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default:
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return (EOPNOTSUPP);
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}
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return (0);
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}
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DEV_MODULE(nmdm, nmdm_modevent, NULL);
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