607 lines
16 KiB
C
607 lines
16 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2002-2020 M. Warner Losh <imp@FreeBSD.org>
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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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#include "opt_bus.h"
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#include "opt_ddb.h"
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#include <sys/param.h>
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#include <sys/conf.h>
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#include <sys/eventhandler.h>
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#include <sys/filio.h>
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#include <sys/lock.h>
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#include <sys/kernel.h>
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#include <sys/malloc.h>
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#include <sys/mutex.h>
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#include <sys/poll.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/condvar.h>
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#include <sys/queue.h>
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#include <machine/bus.h>
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#include <sys/sbuf.h>
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#include <sys/selinfo.h>
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#include <sys/smp.h>
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#include <sys/sysctl.h>
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#include <sys/systm.h>
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#include <sys/uio.h>
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#include <sys/bus.h>
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#include <machine/cpu.h>
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#include <machine/stdarg.h>
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#include <vm/uma.h>
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#include <vm/vm.h>
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#include <ddb/ddb.h>
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STAILQ_HEAD(devq, dev_event_info);
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static struct dev_softc {
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int inuse;
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int nonblock;
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int queued;
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int async;
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struct mtx mtx;
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struct cv cv;
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struct selinfo sel;
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struct devq devq;
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struct sigio *sigio;
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uma_zone_t zone;
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} devsoftc;
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/*
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* This design allows only one reader for /dev/devctl. This is not desirable
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* in the long run, but will get a lot of hair out of this implementation.
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* Maybe we should make this device a clonable device.
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*
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* Also note: we specifically do not attach a device to the device_t tree
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* to avoid potential chicken and egg problems. One could argue that all
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* of this belongs to the root node.
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*/
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#define DEVCTL_DEFAULT_QUEUE_LEN 1000
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static int sysctl_devctl_queue(SYSCTL_HANDLER_ARGS);
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static int devctl_queue_length = DEVCTL_DEFAULT_QUEUE_LEN;
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SYSCTL_PROC(_hw_bus, OID_AUTO, devctl_queue, CTLTYPE_INT | CTLFLAG_RWTUN |
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CTLFLAG_MPSAFE, NULL, 0, sysctl_devctl_queue, "I", "devctl queue length");
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static void devctl_attach_handler(void *arg __unused, device_t dev);
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static void devctl_detach_handler(void *arg __unused, device_t dev,
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enum evhdev_detach state);
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static void devctl_nomatch_handler(void *arg __unused, device_t dev);
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static d_open_t devopen;
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static d_close_t devclose;
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static d_read_t devread;
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static d_ioctl_t devioctl;
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static d_poll_t devpoll;
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static d_kqfilter_t devkqfilter;
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#define DEVCTL_BUFFER (1024 - sizeof(void *))
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struct dev_event_info {
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STAILQ_ENTRY(dev_event_info) dei_link;
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char dei_data[DEVCTL_BUFFER];
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};
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static struct cdevsw dev_cdevsw = {
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.d_version = D_VERSION,
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.d_open = devopen,
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.d_close = devclose,
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.d_read = devread,
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.d_ioctl = devioctl,
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.d_poll = devpoll,
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.d_kqfilter = devkqfilter,
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.d_name = "devctl",
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};
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static void filt_devctl_detach(struct knote *kn);
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static int filt_devctl_read(struct knote *kn, long hint);
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static struct filterops devctl_rfiltops = {
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.f_isfd = 1,
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.f_detach = filt_devctl_detach,
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.f_event = filt_devctl_read,
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};
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static struct cdev *devctl_dev;
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static void devaddq(const char *type, const char *what, device_t dev);
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static struct devctlbridge {
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send_event_f *send_f;
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} devctl_notify_hook = { .send_f = NULL };
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static void
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devctl_init(void)
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{
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int reserve;
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uma_zone_t z;
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devctl_dev = make_dev_credf(MAKEDEV_ETERNAL, &dev_cdevsw, 0, NULL,
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UID_ROOT, GID_WHEEL, 0600, "devctl");
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mtx_init(&devsoftc.mtx, "dev mtx", "devd", MTX_DEF);
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cv_init(&devsoftc.cv, "dev cv");
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STAILQ_INIT(&devsoftc.devq);
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knlist_init_mtx(&devsoftc.sel.si_note, &devsoftc.mtx);
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if (devctl_queue_length > 0) {
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/*
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* Allocate a zone for the messages. Preallocate 2% of these for
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* a reserve. Allow only devctl_queue_length slabs to cap memory
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* usage. The reserve usually allows coverage of surges of
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* events during memory shortages. Normally we won't have to
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* re-use events from the queue, but will in extreme shortages.
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*/
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z = devsoftc.zone = uma_zcreate("DEVCTL",
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sizeof(struct dev_event_info), NULL, NULL, NULL, NULL,
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UMA_ALIGN_PTR, 0);
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reserve = max(devctl_queue_length / 50, 100); /* 2% reserve */
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uma_zone_set_max(z, devctl_queue_length);
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uma_zone_set_maxcache(z, 0);
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uma_zone_reserve(z, reserve);
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uma_prealloc(z, reserve);
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}
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EVENTHANDLER_REGISTER(device_attach, devctl_attach_handler,
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NULL, EVENTHANDLER_PRI_LAST);
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EVENTHANDLER_REGISTER(device_detach, devctl_detach_handler,
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NULL, EVENTHANDLER_PRI_LAST);
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EVENTHANDLER_REGISTER(device_nomatch, devctl_nomatch_handler,
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NULL, EVENTHANDLER_PRI_LAST);
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}
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SYSINIT(devctl_init, SI_SUB_DRIVERS, SI_ORDER_SECOND, devctl_init, NULL);
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/*
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* A device was added to the tree. We are called just after it successfully
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* attaches (that is, probe and attach success for this device). No call
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* is made if a device is merely parented into the tree. See devnomatch
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* if probe fails. If attach fails, no notification is sent (but maybe
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* we should have a different message for this).
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*/
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static void
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devctl_attach_handler(void *arg __unused, device_t dev)
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{
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devaddq("+", device_get_nameunit(dev), dev);
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}
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/*
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* A device was removed from the tree. We are called just before this
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* happens.
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*/
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static void
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devctl_detach_handler(void *arg __unused, device_t dev, enum evhdev_detach state)
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{
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if (state == EVHDEV_DETACH_COMPLETE)
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devaddq("-", device_get_nameunit(dev), dev);
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}
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/*
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* Called when there's no match for this device. This is only called
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* the first time that no match happens, so we don't keep getting this
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* message. Should that prove to be undesirable, we can change it.
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* This is called when all drivers that can attach to a given bus
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* decline to accept this device. Other errors may not be detected.
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*/
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static void
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devctl_nomatch_handler(void *arg __unused, device_t dev)
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{
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devaddq("?", "", dev);
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}
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static int
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devopen(struct cdev *dev, int oflags, int devtype, struct thread *td)
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{
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mtx_lock(&devsoftc.mtx);
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if (devsoftc.inuse) {
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mtx_unlock(&devsoftc.mtx);
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return (EBUSY);
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}
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/* move to init */
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devsoftc.inuse = 1;
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mtx_unlock(&devsoftc.mtx);
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return (0);
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}
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static int
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devclose(struct cdev *dev, int fflag, int devtype, struct thread *td)
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{
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mtx_lock(&devsoftc.mtx);
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devsoftc.inuse = 0;
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devsoftc.nonblock = 0;
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devsoftc.async = 0;
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cv_broadcast(&devsoftc.cv);
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funsetown(&devsoftc.sigio);
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mtx_unlock(&devsoftc.mtx);
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return (0);
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}
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/*
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* The read channel for this device is used to report changes to
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* userland in realtime. We are required to free the data as well as
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* the n1 object because we allocate them separately. Also note that
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* we return one record at a time. If you try to read this device a
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* character at a time, you will lose the rest of the data. Listening
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* programs are expected to cope.
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*/
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static int
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devread(struct cdev *dev, struct uio *uio, int ioflag)
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{
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struct dev_event_info *n1;
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int rv;
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mtx_lock(&devsoftc.mtx);
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while (STAILQ_EMPTY(&devsoftc.devq)) {
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if (devsoftc.nonblock) {
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mtx_unlock(&devsoftc.mtx);
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return (EAGAIN);
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}
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rv = cv_wait_sig(&devsoftc.cv, &devsoftc.mtx);
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if (rv) {
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/*
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* Need to translate ERESTART to EINTR here? -- jake
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*/
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mtx_unlock(&devsoftc.mtx);
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return (rv);
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}
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}
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n1 = STAILQ_FIRST(&devsoftc.devq);
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STAILQ_REMOVE_HEAD(&devsoftc.devq, dei_link);
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devsoftc.queued--;
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mtx_unlock(&devsoftc.mtx);
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rv = uiomove(n1->dei_data, strlen(n1->dei_data), uio);
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uma_zfree(devsoftc.zone, n1);
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return (rv);
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}
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static int
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devioctl(struct cdev *dev, u_long cmd, caddr_t data, int fflag, struct thread *td)
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{
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switch (cmd) {
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case FIONBIO:
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if (*(int*)data)
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devsoftc.nonblock = 1;
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else
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devsoftc.nonblock = 0;
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return (0);
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case FIOASYNC:
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if (*(int*)data)
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devsoftc.async = 1;
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else
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devsoftc.async = 0;
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return (0);
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case FIOSETOWN:
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return fsetown(*(int *)data, &devsoftc.sigio);
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case FIOGETOWN:
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*(int *)data = fgetown(&devsoftc.sigio);
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return (0);
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/* (un)Support for other fcntl() calls. */
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case FIOCLEX:
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case FIONCLEX:
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case FIONREAD:
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default:
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break;
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}
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return (ENOTTY);
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}
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static int
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devpoll(struct cdev *dev, int events, struct thread *td)
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{
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int revents = 0;
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mtx_lock(&devsoftc.mtx);
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if (events & (POLLIN | POLLRDNORM)) {
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if (!STAILQ_EMPTY(&devsoftc.devq))
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revents = events & (POLLIN | POLLRDNORM);
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else
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selrecord(td, &devsoftc.sel);
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}
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mtx_unlock(&devsoftc.mtx);
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return (revents);
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}
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static int
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devkqfilter(struct cdev *dev, struct knote *kn)
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{
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int error;
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if (kn->kn_filter == EVFILT_READ) {
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kn->kn_fop = &devctl_rfiltops;
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knlist_add(&devsoftc.sel.si_note, kn, 0);
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error = 0;
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} else
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error = EINVAL;
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return (error);
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}
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static void
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filt_devctl_detach(struct knote *kn)
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{
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knlist_remove(&devsoftc.sel.si_note, kn, 0);
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}
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static int
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filt_devctl_read(struct knote *kn, long hint)
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{
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kn->kn_data = devsoftc.queued;
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return (kn->kn_data != 0);
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}
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/**
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* @brief Return whether the userland process is running
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*/
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bool
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devctl_process_running(void)
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{
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return (devsoftc.inuse == 1);
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}
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static struct dev_event_info *
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devctl_alloc_dei(void)
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{
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struct dev_event_info *dei = NULL;
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mtx_lock(&devsoftc.mtx);
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if (devctl_queue_length == 0)
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goto out;
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dei = uma_zalloc(devsoftc.zone, M_NOWAIT);
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if (dei == NULL)
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dei = uma_zalloc(devsoftc.zone, M_NOWAIT | M_USE_RESERVE);
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if (dei == NULL) {
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/*
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* Guard against no items in the queue. Normally, this won't
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* happen, but if lots of events happen all at once and there's
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* a chance we're out of allocated space but none have yet been
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* queued when we get here, leaving nothing to steal. This can
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* also happen with error injection. Fail safe by returning
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* NULL in that case..
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*/
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if (devsoftc.queued == 0)
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goto out;
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dei = STAILQ_FIRST(&devsoftc.devq);
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STAILQ_REMOVE_HEAD(&devsoftc.devq, dei_link);
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devsoftc.queued--;
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}
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MPASS(dei != NULL);
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*dei->dei_data = '\0';
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out:
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mtx_unlock(&devsoftc.mtx);
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return (dei);
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}
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static struct dev_event_info *
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devctl_alloc_dei_sb(struct sbuf *sb)
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{
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struct dev_event_info *dei;
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dei = devctl_alloc_dei();
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if (dei != NULL)
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sbuf_new(sb, dei->dei_data, sizeof(dei->dei_data), SBUF_FIXEDLEN);
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return (dei);
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}
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static void
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devctl_free_dei(struct dev_event_info *dei)
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{
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uma_zfree(devsoftc.zone, dei);
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}
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static void
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devctl_queue(struct dev_event_info *dei)
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{
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mtx_lock(&devsoftc.mtx);
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STAILQ_INSERT_TAIL(&devsoftc.devq, dei, dei_link);
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devsoftc.queued++;
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cv_broadcast(&devsoftc.cv);
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KNOTE_LOCKED(&devsoftc.sel.si_note, 0);
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mtx_unlock(&devsoftc.mtx);
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selwakeup(&devsoftc.sel);
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if (devsoftc.async && devsoftc.sigio != NULL)
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pgsigio(&devsoftc.sigio, SIGIO, 0);
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}
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/**
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* @brief Send a 'notification' to userland, using standard ways
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*/
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void
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devctl_notify(const char *system, const char *subsystem, const char *type,
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const char *data)
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{
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struct dev_event_info *dei;
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struct sbuf sb;
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if (system == NULL || subsystem == NULL || type == NULL)
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return;
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if (devctl_notify_hook.send_f != NULL)
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devctl_notify_hook.send_f(system, subsystem, type, data);
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dei = devctl_alloc_dei_sb(&sb);
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if (dei == NULL)
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return;
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sbuf_cpy(&sb, "!system=");
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sbuf_cat(&sb, system);
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sbuf_cat(&sb, " subsystem=");
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sbuf_cat(&sb, subsystem);
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sbuf_cat(&sb, " type=");
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sbuf_cat(&sb, type);
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if (data != NULL) {
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sbuf_putc(&sb, ' ');
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sbuf_cat(&sb, data);
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}
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sbuf_putc(&sb, '\n');
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if (sbuf_finish(&sb) != 0)
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devctl_free_dei(dei); /* overflow -> drop it */
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else
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devctl_queue(dei);
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}
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/*
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* Common routine that tries to make sending messages as easy as possible.
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* We allocate memory for the data, copy strings into that, but do not
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* free it unless there's an error. The dequeue part of the driver should
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* free the data. We don't send data when the device is disabled. We do
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* send data, even when we have no listeners, because we wish to avoid
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* races relating to startup and restart of listening applications.
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*
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* devaddq is designed to string together the type of event, with the
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* object of that event, plus the plug and play info and location info
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* for that event. This is likely most useful for devices, but less
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* useful for other consumers of this interface. Those should use
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* the devctl_notify() interface instead.
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*
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* Output:
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* ${type}${what} at $(location dev) $(pnp-info dev) on $(parent dev)
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*/
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static void
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devaddq(const char *type, const char *what, device_t dev)
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{
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struct dev_event_info *dei;
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const char *parstr;
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struct sbuf sb;
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size_t beginlen;
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dei = devctl_alloc_dei_sb(&sb);
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if (dei == NULL)
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return;
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sbuf_cpy(&sb, type);
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sbuf_cat(&sb, what);
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sbuf_cat(&sb, " at ");
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beginlen = sbuf_len(&sb);
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/* Add in the location */
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bus_child_location(dev, &sb);
|
|
sbuf_putc(&sb, ' ');
|
|
|
|
/* Add in pnpinfo */
|
|
bus_child_pnpinfo(dev, &sb);
|
|
|
|
/* Get the parent of this device, or / if high enough in the tree. */
|
|
if (device_get_parent(dev) == NULL)
|
|
parstr = "."; /* Or '/' ? */
|
|
else
|
|
parstr = device_get_nameunit(device_get_parent(dev));
|
|
sbuf_cat(&sb, " on ");
|
|
sbuf_cat(&sb, parstr);
|
|
sbuf_putc(&sb, '\n');
|
|
if (sbuf_finish(&sb) != 0)
|
|
goto bad;
|
|
if (devctl_notify_hook.send_f != NULL) {
|
|
const char *t;
|
|
|
|
switch (*type) {
|
|
case '+':
|
|
t = "ATTACH";
|
|
break;
|
|
case '-':
|
|
t = "DETACH";
|
|
break;
|
|
default:
|
|
t = "NOMATCH";
|
|
break;
|
|
}
|
|
devctl_notify_hook.send_f("device",
|
|
what, t, sbuf_data(&sb) + beginlen);
|
|
}
|
|
devctl_queue(dei);
|
|
return;
|
|
bad:
|
|
devctl_free_dei(dei);
|
|
}
|
|
|
|
static int
|
|
sysctl_devctl_queue(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int q, error;
|
|
|
|
q = devctl_queue_length;
|
|
error = sysctl_handle_int(oidp, &q, 0, req);
|
|
if (error || !req->newptr)
|
|
return (error);
|
|
if (q < 0)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* When set as a tunable, we've not yet initialized the mutex.
|
|
* It is safe to just assign to devctl_queue_length and return
|
|
* as we're racing no one. We'll use whatever value set in
|
|
* devinit.
|
|
*/
|
|
if (!mtx_initialized(&devsoftc.mtx)) {
|
|
devctl_queue_length = q;
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* XXX It's hard to grow or shrink the UMA zone. Only allow
|
|
* disabling the queue size for the moment until underlying
|
|
* UMA issues can be sorted out.
|
|
*/
|
|
if (q != 0)
|
|
return (EINVAL);
|
|
if (q == devctl_queue_length)
|
|
return (0);
|
|
mtx_lock(&devsoftc.mtx);
|
|
devctl_queue_length = 0;
|
|
uma_zdestroy(devsoftc.zone);
|
|
devsoftc.zone = 0;
|
|
mtx_unlock(&devsoftc.mtx);
|
|
return (0);
|
|
}
|
|
|
|
/**
|
|
* @brief safely quotes strings that might have double quotes in them.
|
|
*
|
|
* The devctl protocol relies on quoted strings having matching quotes.
|
|
* This routine quotes any internal quotes so the resulting string
|
|
* is safe to pass to snprintf to construct, for example pnp info strings.
|
|
*
|
|
* @param sb sbuf to place the characters into
|
|
* @param src Original buffer.
|
|
*/
|
|
void
|
|
devctl_safe_quote_sb(struct sbuf *sb, const char *src)
|
|
{
|
|
while (*src != '\0') {
|
|
if (*src == '"' || *src == '\\')
|
|
sbuf_putc(sb, '\\');
|
|
sbuf_putc(sb, *src++);
|
|
}
|
|
}
|
|
|
|
void
|
|
devctl_set_notify_hook(send_event_f *hook)
|
|
{
|
|
devctl_notify_hook.send_f = hook;
|
|
}
|
|
|
|
void
|
|
devctl_unset_notify_hook(void)
|
|
{
|
|
devctl_notify_hook.send_f = NULL;
|
|
}
|
|
|