/* $OpenBSD: hotplug.c,v 1.9 2009/11/09 17:53:39 nicm Exp $ */ /* * Copyright (c) 2004 Alexander Yurchenko <grange@openbsd.org> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * Device attachment and detachment notifications. */ #include <sys/param.h> #include <sys/systm.h> #include <sys/conf.h> #include <sys/device.h> #include <sys/fcntl.h> #include <sys/hotplug.h> #include <sys/ioctl.h> #include <sys/poll.h> #include <sys/vnode.h> #define HOTPLUG_MAXEVENTS 16 static int opened; static struct hotplug_event evqueue[HOTPLUG_MAXEVENTS]; static int evqueue_head, evqueue_tail, evqueue_count; static struct selinfo hotplug_sel; void filt_hotplugrdetach(struct knote *); int filt_hotplugread(struct knote *, long); struct filterops hotplugread_filtops = { 1, NULL, filt_hotplugrdetach, filt_hotplugread}; #define EVQUEUE_NEXT(p) (p == HOTPLUG_MAXEVENTS - 1 ? 0 : p + 1) int hotplug_put_event(struct hotplug_event *); int hotplug_get_event(struct hotplug_event *); void hotplugattach(int); void hotplugattach(int count) { opened = 0; evqueue_head = 0; evqueue_tail = 0; evqueue_count = 0; } void hotplug_device_attach(enum devclass class, char *name) { struct hotplug_event he; he.he_type = HOTPLUG_DEVAT; he.he_devclass = class; strlcpy(he.he_devname, name, sizeof(he.he_devname)); hotplug_put_event(&he); } void hotplug_device_detach(enum devclass class, char *name) { struct hotplug_event he; he.he_type = HOTPLUG_DEVDT; he.he_devclass = class; strlcpy(he.he_devname, name, sizeof(he.he_devname)); hotplug_put_event(&he); } int hotplug_put_event(struct hotplug_event *he) { if (evqueue_count == HOTPLUG_MAXEVENTS && opened) { printf("hotplug: event lost, queue full\n"); return (1); } evqueue[evqueue_head] = *he; evqueue_head = EVQUEUE_NEXT(evqueue_head); if (evqueue_count == HOTPLUG_MAXEVENTS) evqueue_tail = EVQUEUE_NEXT(evqueue_tail); else evqueue_count++; wakeup(&evqueue); selwakeup(&hotplug_sel); return (0); } int hotplug_get_event(struct hotplug_event *he) { int s; if (evqueue_count == 0) return (1); s = splbio(); *he = evqueue[evqueue_tail]; evqueue_tail = EVQUEUE_NEXT(evqueue_tail); evqueue_count--; splx(s); return (0); } int hotplugopen(dev_t dev, int flag, int mode, struct proc *p) { if (minor(dev) != 0) return (ENXIO); if ((flag & FWRITE)) return (EPERM); if (opened) return (EBUSY); opened = 1; return (0); } int hotplugclose(dev_t dev, int flag, int mode, struct proc *p) { struct hotplug_event he; while (hotplug_get_event(&he) == 0) ; opened = 0; return (0); } int hotplugread(dev_t dev, struct uio *uio, int flags) { struct hotplug_event he; int error; if (uio->uio_resid != sizeof(he)) return (EINVAL); again: if (hotplug_get_event(&he) == 0) return (uiomove(&he, sizeof(he), uio)); if (flags & IO_NDELAY) return (EAGAIN); error = tsleep(evqueue, PRIBIO | PCATCH, "htplev", 0); if (error) return (error); goto again; } int hotplugioctl(dev_t dev, u_long cmd, caddr_t data, int flag, struct proc *p) { switch (cmd) { case FIOASYNC: /* ignore */ case FIONBIO: /* handled in the upper fs layer */ break; default: return (ENOTTY); } return (0); } int hotplugpoll(dev_t dev, int events, struct proc *p) { int revents = 0; if (events & (POLLIN | POLLRDNORM)) { if (evqueue_count > 0) revents |= events & (POLLIN | POLLRDNORM); else selrecord(p, &hotplug_sel); } return (revents); } int hotplugkqfilter(dev_t dev, struct knote *kn) { struct klist *klist; int s; switch (kn->kn_filter) { case EVFILT_READ: klist = &hotplug_sel.si_note; kn->kn_fop = &hotplugread_filtops; break; default: return (1); } s = splbio(); SLIST_INSERT_HEAD(klist, kn, kn_selnext); splx(s); return (0); } void filt_hotplugrdetach(struct knote *kn) { int s; s = splbio(); SLIST_REMOVE(&hotplug_sel.si_note, kn, knote, kn_selnext); splx(s); } int filt_hotplugread(struct knote *kn, long hint) { kn->kn_data = evqueue_count; return (evqueue_count > 0); }