diff --git a/sys/kern/sys_eventfd.c b/sys/kern/sys_eventfd.c index 3fdb4afc7850..8a884e4c9a55 100644 --- a/sys/kern/sys_eventfd.c +++ b/sys/kern/sys_eventfd.c @@ -1,349 +1,347 @@ /*- * SPDX-License-Identifier: BSD-2-Clause-FreeBSD * - * Copyright (c) 2007 Roman Divacky * Copyright (c) 2014 Dmitry Chagin - * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #include __FBSDID("$FreeBSD$"); #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include _Static_assert(EFD_CLOEXEC == O_CLOEXEC, "Mismatched EFD_CLOEXEC"); _Static_assert(EFD_NONBLOCK == O_NONBLOCK, "Mismatched EFD_NONBLOCK"); MALLOC_DEFINE(M_EVENTFD, "eventfd", "eventfd structures"); static fo_rdwr_t eventfd_read; static fo_rdwr_t eventfd_write; static fo_ioctl_t eventfd_ioctl; static fo_poll_t eventfd_poll; static fo_kqfilter_t eventfd_kqfilter; static fo_stat_t eventfd_stat; static fo_close_t eventfd_close; static fo_fill_kinfo_t eventfd_fill_kinfo; static struct fileops eventfdops = { .fo_read = eventfd_read, .fo_write = eventfd_write, .fo_truncate = invfo_truncate, .fo_ioctl = eventfd_ioctl, .fo_poll = eventfd_poll, .fo_kqfilter = eventfd_kqfilter, .fo_stat = eventfd_stat, .fo_close = eventfd_close, .fo_chmod = invfo_chmod, .fo_chown = invfo_chown, .fo_sendfile = invfo_sendfile, .fo_fill_kinfo = eventfd_fill_kinfo, .fo_flags = DFLAG_PASSABLE }; static void filt_eventfddetach(struct knote *kn); static int filt_eventfdread(struct knote *kn, long hint); static int filt_eventfdwrite(struct knote *kn, long hint); static struct filterops eventfd_rfiltops = { .f_isfd = 1, .f_detach = filt_eventfddetach, .f_event = filt_eventfdread }; static struct filterops eventfd_wfiltops = { .f_isfd = 1, .f_detach = filt_eventfddetach, .f_event = filt_eventfdwrite }; struct eventfd { eventfd_t efd_count; uint32_t efd_flags; struct selinfo efd_sel; struct mtx efd_lock; }; int eventfd_create_file(struct thread *td, struct file *fp, uint32_t initval, int flags) { struct eventfd *efd; int fflags; AUDIT_ARG_FFLAGS(flags); AUDIT_ARG_VALUE(initval); efd = malloc(sizeof(*efd), M_EVENTFD, M_WAITOK | M_ZERO); efd->efd_flags = flags; efd->efd_count = initval; mtx_init(&efd->efd_lock, "eventfd", NULL, MTX_DEF); knlist_init_mtx(&efd->efd_sel.si_note, &efd->efd_lock); fflags = FREAD | FWRITE; if ((flags & EFD_NONBLOCK) != 0) fflags |= FNONBLOCK; finit(fp, fflags, DTYPE_EVENTFD, efd, &eventfdops); return (0); } static int eventfd_close(struct file *fp, struct thread *td) { struct eventfd *efd; efd = fp->f_data; seldrain(&efd->efd_sel); knlist_destroy(&efd->efd_sel.si_note); mtx_destroy(&efd->efd_lock); free(efd, M_EVENTFD); return (0); } static int eventfd_read(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) { struct eventfd *efd; eventfd_t count; int error; if (uio->uio_resid < sizeof(eventfd_t)) return (EINVAL); error = 0; efd = fp->f_data; mtx_lock(&efd->efd_lock); while (error == 0 && efd->efd_count == 0) { if ((fp->f_flag & FNONBLOCK) != 0) { mtx_unlock(&efd->efd_lock); return (EAGAIN); } error = mtx_sleep(&efd->efd_count, &efd->efd_lock, PCATCH, "efdrd", 0); } if (error == 0) { MPASS(efd->efd_count > 0); if ((efd->efd_flags & EFD_SEMAPHORE) != 0) { count = 1; --efd->efd_count; } else { count = efd->efd_count; efd->efd_count = 0; } KNOTE_LOCKED(&efd->efd_sel.si_note, 0); selwakeup(&efd->efd_sel); wakeup(&efd->efd_count); mtx_unlock(&efd->efd_lock); error = uiomove(&count, sizeof(eventfd_t), uio); } else mtx_unlock(&efd->efd_lock); return (error); } static int eventfd_write(struct file *fp, struct uio *uio, struct ucred *active_cred, int flags, struct thread *td) { struct eventfd *efd; eventfd_t count; int error; if (uio->uio_resid < sizeof(eventfd_t)) return (EINVAL); error = uiomove(&count, sizeof(eventfd_t), uio); if (error != 0) return (error); if (count == UINT64_MAX) return (EINVAL); efd = fp->f_data; mtx_lock(&efd->efd_lock); retry: if (UINT64_MAX - efd->efd_count <= count) { if ((fp->f_flag & FNONBLOCK) != 0) { mtx_unlock(&efd->efd_lock); /* Do not not return the number of bytes written */ uio->uio_resid += sizeof(eventfd_t); return (EAGAIN); } error = mtx_sleep(&efd->efd_count, &efd->efd_lock, PCATCH, "efdwr", 0); if (error == 0) goto retry; } if (error == 0) { MPASS(UINT64_MAX - efd->efd_count > count); efd->efd_count += count; KNOTE_LOCKED(&efd->efd_sel.si_note, 0); selwakeup(&efd->efd_sel); wakeup(&efd->efd_count); } mtx_unlock(&efd->efd_lock); return (error); } static int eventfd_poll(struct file *fp, int events, struct ucred *active_cred, struct thread *td) { struct eventfd *efd; int revents; efd = fp->f_data; revents = 0; mtx_lock(&efd->efd_lock); if ((events & (POLLIN | POLLRDNORM)) != 0 && efd->efd_count > 0) revents |= events & (POLLIN | POLLRDNORM); if ((events & (POLLOUT | POLLWRNORM)) != 0 && UINT64_MAX - 1 > efd->efd_count) revents |= events & (POLLOUT | POLLWRNORM); if (revents == 0) selrecord(td, &efd->efd_sel); mtx_unlock(&efd->efd_lock); return (revents); } static int eventfd_kqfilter(struct file *fp, struct knote *kn) { struct eventfd *efd = fp->f_data; mtx_lock(&efd->efd_lock); switch (kn->kn_filter) { case EVFILT_READ: kn->kn_fop = &eventfd_rfiltops; break; case EVFILT_WRITE: kn->kn_fop = &eventfd_wfiltops; break; default: mtx_unlock(&efd->efd_lock); return (EINVAL); } kn->kn_hook = efd; knlist_add(&efd->efd_sel.si_note, kn, 1); mtx_unlock(&efd->efd_lock); return (0); } static void filt_eventfddetach(struct knote *kn) { struct eventfd *efd = kn->kn_hook; mtx_lock(&efd->efd_lock); knlist_remove(&efd->efd_sel.si_note, kn, 1); mtx_unlock(&efd->efd_lock); } static int filt_eventfdread(struct knote *kn, long hint) { struct eventfd *efd = kn->kn_hook; int ret; mtx_assert(&efd->efd_lock, MA_OWNED); kn->kn_data = (int64_t)efd->efd_count; ret = efd->efd_count > 0; return (ret); } static int filt_eventfdwrite(struct knote *kn, long hint) { struct eventfd *efd = kn->kn_hook; int ret; mtx_assert(&efd->efd_lock, MA_OWNED); kn->kn_data = (int64_t)(UINT64_MAX - 1 - efd->efd_count); ret = UINT64_MAX - 1 > efd->efd_count; return (ret); } static int eventfd_ioctl(struct file *fp, u_long cmd, void *data, struct ucred *active_cred, struct thread *td) { switch (cmd) { case FIONBIO: case FIOASYNC: return (0); } return (ENOTTY); } static int eventfd_stat(struct file *fp, struct stat *st, struct ucred *active_cred, struct thread *td) { bzero((void *)st, sizeof *st); st->st_mode = S_IFIFO; return (0); } static int eventfd_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) { struct eventfd *efd = fp->f_data; kif->kf_type = KF_TYPE_EVENTFD; mtx_lock(&efd->efd_lock); kif->kf_un.kf_eventfd.kf_eventfd_value = efd->efd_count; kif->kf_un.kf_eventfd.kf_eventfd_flags = efd->efd_flags; mtx_unlock(&efd->efd_lock); return (0); }