+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
+ *
+ */
+/*-
+ * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org>
+ * 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.
+ */
+/*
+ * @(#)kern_event.c 1.0 (3/31/2000)
+ */
+#include <stdint.h>
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/filedesc.h>
+#include <sys/kernel.h>
+#include <sys/proc_internal.h>
+#include <sys/kauth.h>
+#include <sys/malloc.h>
+#include <sys/unistd.h>
+#include <sys/file_internal.h>
+#include <sys/fcntl.h>
+#include <sys/select.h>
+#include <sys/queue.h>
+#include <sys/event.h>
+#include <sys/eventvar.h>
+#include <sys/protosw.h>
+#include <sys/socket.h>
+#include <sys/socketvar.h>
+#include <sys/stat.h>
+#include <sys/sysctl.h>
+#include <sys/uio.h>
+#include <sys/sysproto.h>
+#include <sys/user.h>
+#include <sys/vnode_internal.h>
+#include <string.h>
+#include <sys/proc_info.h>
+
+#include <kern/lock.h>
+#include <kern/clock.h>
+#include <kern/thread_call.h>
+#include <kern/sched_prim.h>
+#include <kern/zalloc.h>
+#include <kern/assert.h>
+
+#include <libkern/libkern.h>
+#include "net/net_str_id.h"
+
+#include <mach/task.h>
+
+#if VM_PRESSURE_EVENTS
+#include <kern/vm_pressure.h>
+#endif
+
+MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system");
+
+#define KQ_EVENT NULL
+
+static inline void kqlock(struct kqueue *kq);
+static inline void kqunlock(struct kqueue *kq);
+
+static int kqlock2knoteuse(struct kqueue *kq, struct knote *kn);
+static int kqlock2knoteusewait(struct kqueue *kq, struct knote *kn);
+static int kqlock2knotedrop(struct kqueue *kq, struct knote *kn);
+static int knoteuse2kqlock(struct kqueue *kq, struct knote *kn);
+
+static void kqueue_wakeup(struct kqueue *kq, int closed);
+static int kqueue_read(struct fileproc *fp, struct uio *uio,
+ int flags, vfs_context_t ctx);
+static int kqueue_write(struct fileproc *fp, struct uio *uio,
+ int flags, vfs_context_t ctx);
+static int kqueue_ioctl(struct fileproc *fp, u_long com, caddr_t data,
+ vfs_context_t ctx);
+static int kqueue_select(struct fileproc *fp, int which, void *wql,
+ vfs_context_t ctx);
+static int kqueue_close(struct fileglob *fg, vfs_context_t ctx);
+static int kqueue_kqfilter(struct fileproc *fp, struct knote *kn, vfs_context_t ctx);
+static int kqueue_drain(struct fileproc *fp, vfs_context_t ctx);
+extern int kqueue_stat(struct fileproc *fp, void *ub, int isstat64, vfs_context_t ctx);
+
+static struct fileops kqueueops = {
+ .fo_read = kqueue_read,
+ .fo_write = kqueue_write,
+ .fo_ioctl = kqueue_ioctl,
+ .fo_select = kqueue_select,
+ .fo_close = kqueue_close,
+ .fo_kqfilter = kqueue_kqfilter,
+ .fo_drain = kqueue_drain,
+};
+
+static int kevent_internal(struct proc *p, int iskev64, user_addr_t changelist,
+ int nchanges, user_addr_t eventlist, int nevents, int fd,
+ user_addr_t utimeout, unsigned int flags, int32_t *retval);
+static int kevent_copyin(user_addr_t *addrp, struct kevent64_s *kevp, struct proc *p, int iskev64);
+static int kevent_copyout(struct kevent64_s *kevp, user_addr_t *addrp, struct proc *p, int iskev64);
+char * kevent_description(struct kevent64_s *kevp, char *s, size_t n);
+
+static int kevent_callback(struct kqueue *kq, struct kevent64_s *kevp, void *data);
+static void kevent_continue(struct kqueue *kq, void *data, int error);
+static void kqueue_scan_continue(void *contp, wait_result_t wait_result);
+static int kqueue_process(struct kqueue *kq, kevent_callback_t callback,
+ void *data, int *countp, struct proc *p);
+static int kqueue_begin_processing(struct kqueue *kq);
+static void kqueue_end_processing(struct kqueue *kq);
+static int knote_process(struct knote *kn, kevent_callback_t callback,
+ void *data, struct kqtailq *inprocessp, struct proc *p);
+static void knote_put(struct knote *kn);
+static int knote_fdpattach(struct knote *kn, struct filedesc *fdp, struct proc *p);
+static void knote_drop(struct knote *kn, struct proc *p);
+static void knote_activate(struct knote *kn, int);
+static void knote_deactivate(struct knote *kn);
+static void knote_enqueue(struct knote *kn);
+static void knote_dequeue(struct knote *kn);
+static struct knote *knote_alloc(void);
+static void knote_free(struct knote *kn);
+
+static int filt_fileattach(struct knote *kn);
+static struct filterops file_filtops = {
+ .f_isfd = 1,
+ .f_attach = filt_fileattach,
+};
+
+static void filt_kqdetach(struct knote *kn);
+static int filt_kqueue(struct knote *kn, long hint);
+static struct filterops kqread_filtops = {
+ .f_isfd = 1,
+ .f_detach = filt_kqdetach,
+ .f_event = filt_kqueue,
+};
+
+/*
+ * placeholder for not-yet-implemented filters
+ */
+static int filt_badattach(struct knote *kn);
+static struct filterops bad_filtops = {
+ .f_attach = filt_badattach,
+};
+
+static int filt_procattach(struct knote *kn);
+static void filt_procdetach(struct knote *kn);
+static int filt_proc(struct knote *kn, long hint);
+static struct filterops proc_filtops = {
+ .f_attach = filt_procattach,
+ .f_detach = filt_procdetach,
+ .f_event = filt_proc,
+};
+
+#if VM_PRESSURE_EVENTS
+static int filt_vmattach(struct knote *kn);
+static void filt_vmdetach(struct knote *kn);
+static int filt_vm(struct knote *kn, long hint);
+static struct filterops vm_filtops = {
+ .f_attach = filt_vmattach,
+ .f_detach = filt_vmdetach,
+ .f_event = filt_vm,
+};
+#endif /* VM_PRESSURE_EVENTS */
+
+extern struct filterops fs_filtops;
+
+extern struct filterops sig_filtops;
+
+/* Timer filter */
+static int filt_timerattach(struct knote *kn);
+static void filt_timerdetach(struct knote *kn);
+static int filt_timer(struct knote *kn, long hint);
+static void filt_timertouch(struct knote *kn, struct kevent64_s *kev,
+ long type);
+static struct filterops timer_filtops = {
+ .f_attach = filt_timerattach,
+ .f_detach = filt_timerdetach,
+ .f_event = filt_timer,
+ .f_touch = filt_timertouch,
+};
+
+/* Helpers */
+
+static void filt_timerexpire(void *knx, void *param1);
+static int filt_timervalidate(struct knote *kn);
+static void filt_timerupdate(struct knote *kn);
+static void filt_timercancel(struct knote *kn);
+
+#define TIMER_RUNNING 0x1
+#define TIMER_CANCELWAIT 0x2
+
+static lck_mtx_t _filt_timerlock;
+static void filt_timerlock(void);
+static void filt_timerunlock(void);
+
+static zone_t knote_zone;
+
+#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
+
+#if 0
+extern struct filterops aio_filtops;
+#endif
+
+/* Mach portset filter */
+extern struct filterops machport_filtops;
+
+/* User filter */
+static int filt_userattach(struct knote *kn);
+static void filt_userdetach(struct knote *kn);
+static int filt_user(struct knote *kn, long hint);
+static void filt_usertouch(struct knote *kn, struct kevent64_s *kev,
+ long type);
+static struct filterops user_filtops = {
+ .f_attach = filt_userattach,
+ .f_detach = filt_userdetach,
+ .f_event = filt_user,
+ .f_touch = filt_usertouch,
+};
+
+/*
+ * Table for for all system-defined filters.
+ */
+static struct filterops *sysfilt_ops[] = {
+ &file_filtops, /* EVFILT_READ */
+ &file_filtops, /* EVFILT_WRITE */
+#if 0
+ &aio_filtops, /* EVFILT_AIO */
+#else
+ &bad_filtops, /* EVFILT_AIO */
+#endif
+ &file_filtops, /* EVFILT_VNODE */
+ &proc_filtops, /* EVFILT_PROC */
+ &sig_filtops, /* EVFILT_SIGNAL */
+ &timer_filtops, /* EVFILT_TIMER */
+ &machport_filtops, /* EVFILT_MACHPORT */
+ &fs_filtops, /* EVFILT_FS */
+ &user_filtops, /* EVFILT_USER */
+ &bad_filtops, /* unused */
+#if VM_PRESSURE_EVENTS
+ &vm_filtops, /* EVFILT_VM */
+#else
+ &bad_filtops, /* EVFILT_VM */
+#endif
+ &file_filtops, /* EVFILT_SOCK */
+};
+
+/*
+ * kqueue/note lock attributes and implementations
+ *
+ * kqueues have locks, while knotes have use counts
+ * Most of the knote state is guarded by the object lock.
+ * the knote "inuse" count and status use the kqueue lock.
+ */
+lck_grp_attr_t * kq_lck_grp_attr;
+lck_grp_t * kq_lck_grp;
+lck_attr_t * kq_lck_attr;
+
+static inline void
+kqlock(struct kqueue *kq)
+{
+ lck_spin_lock(&kq->kq_lock);
+}
+
+static inline void
+kqunlock(struct kqueue *kq)
+{
+ lck_spin_unlock(&kq->kq_lock);
+}
+
+/*
+ * Convert a kq lock to a knote use referece.
+ *
+ * If the knote is being dropped, we can't get
+ * a use reference, so just return with it
+ * still locked.
+ *
+ * - kq locked at entry
+ * - unlock on exit if we get the use reference
+ */
+static int
+kqlock2knoteuse(struct kqueue *kq, struct knote *kn)
+{
+ if (kn->kn_status & KN_DROPPING)
+ return 0;
+ kn->kn_inuse++;
+ kqunlock(kq);
+ return 1;
+ }
+
+/*
+ * Convert a kq lock to a knote use referece,
+ * but wait for attach and drop events to complete.
+ *
+ * If the knote is being dropped, we can't get
+ * a use reference, so just return with it
+ * still locked.
+ *
+ * - kq locked at entry
+ * - kq always unlocked on exit
+ */
+static int
+kqlock2knoteusewait(struct kqueue *kq, struct knote *kn)
+{
+ if ((kn->kn_status & (KN_DROPPING | KN_ATTACHING)) != 0) {
+ kn->kn_status |= KN_USEWAIT;
+ wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_UNINT, 0);
+ kqunlock(kq);
+ thread_block(THREAD_CONTINUE_NULL);
+ return 0;
+ }
+ kn->kn_inuse++;
+ kqunlock(kq);
+ return 1;
+ }
+
+
+/*
+ * Convert from a knote use reference back to kq lock.
+ *
+ * Drop a use reference and wake any waiters if
+ * this is the last one.
+ *
+ * The exit return indicates if the knote is
+ * still alive - but the kqueue lock is taken
+ * unconditionally.
+ */
+static int
+knoteuse2kqlock(struct kqueue *kq, struct knote *kn)
+{
+ kqlock(kq);
+ if (--kn->kn_inuse == 0) {
+ if ((kn->kn_status & KN_ATTACHING) != 0) {
+ kn->kn_status &= ~KN_ATTACHING;
+ }
+ if ((kn->kn_status & KN_USEWAIT) != 0) {
+ kn->kn_status &= ~KN_USEWAIT;
+ wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_AWAKENED);
+ }
+ }
+ return ((kn->kn_status & KN_DROPPING) == 0);
+ }
+
+/*
+ * Convert a kq lock to a knote drop referece.
+ *
+ * If the knote is in use, wait for the use count
+ * to subside. We first mark our intention to drop
+ * it - keeping other users from "piling on."
+ * If we are too late, we have to wait for the
+ * other drop to complete.
+ *
+ * - kq locked at entry
+ * - always unlocked on exit.
+ * - caller can't hold any locks that would prevent
+ * the other dropper from completing.
+ */
+static int
+kqlock2knotedrop(struct kqueue *kq, struct knote *kn)
+{
+ int oktodrop;
+
+ oktodrop = ((kn->kn_status & (KN_DROPPING | KN_ATTACHING)) == 0);
+ kn->kn_status |= KN_DROPPING;
+ if (oktodrop) {
+ if (kn->kn_inuse == 0) {
+ kqunlock(kq);
+ return oktodrop;
+ }
+ }
+ kn->kn_status |= KN_USEWAIT;
+ wait_queue_assert_wait((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_UNINT, 0);
+ kqunlock(kq);
+ thread_block(THREAD_CONTINUE_NULL);
+ return oktodrop;
+}
+
+/*
+ * Release a knote use count reference.
+ */
+static void
+knote_put(struct knote *kn)
+{
+ struct kqueue *kq = kn->kn_kq;
+
+ kqlock(kq);
+ if (--kn->kn_inuse == 0) {
+ if ((kn->kn_status & KN_USEWAIT) != 0) {
+ kn->kn_status &= ~KN_USEWAIT;
+ wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_status, THREAD_AWAKENED);
+ }
+ }
+ kqunlock(kq);
+ }
+
+static int
+filt_fileattach(struct knote *kn)
+{
+
+ return (fo_kqfilter(kn->kn_fp, kn, vfs_context_current()));
+}
+
+#define f_flag f_fglob->fg_flag
+#define f_type f_fglob->fg_type
+#define f_msgcount f_fglob->fg_msgcount
+#define f_cred f_fglob->fg_cred
+#define f_ops f_fglob->fg_ops
+#define f_offset f_fglob->fg_offset
+#define f_data f_fglob->fg_data
+
+static void
+filt_kqdetach(struct knote *kn)
+{
+ struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+
+ kqlock(kq);
+ KNOTE_DETACH(&kq->kq_sel.si_note, kn);
+ kqunlock(kq);
+}
+
+/*ARGSUSED*/
+static int
+filt_kqueue(struct knote *kn, __unused long hint)
+{
+ struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data;
+
+ kn->kn_data = kq->kq_count;
+ return (kn->kn_data > 0);
+}
+
+static int
+filt_procattach(struct knote *kn)
+{
+ struct proc *p;
+
+ assert(PID_MAX < NOTE_PDATAMASK);
+
+ if ((kn->kn_sfflags & (NOTE_TRACK | NOTE_TRACKERR | NOTE_CHILD)) != 0)
+ return(ENOTSUP);
+
+ p = proc_find(kn->kn_id);
+ if (p == NULL) {
+ return (ESRCH);
+ }
+
+ const int NoteExitStatusBits = NOTE_EXIT | NOTE_EXITSTATUS;
+
+ if ((kn->kn_sfflags & NoteExitStatusBits) == NoteExitStatusBits)
+ do {
+ pid_t selfpid = proc_selfpid();
+
+ if (p->p_ppid == selfpid)
+ break; /* parent => ok */
+
+ if ((p->p_lflag & P_LTRACED) != 0 &&
+ (p->p_oppid == selfpid))
+ break; /* parent-in-waiting => ok */
+
+ proc_rele(p);
+ return (EACCES);
+ } while (0);
+
+ proc_klist_lock();
+
+ kn->kn_flags |= EV_CLEAR; /* automatically set */
+ kn->kn_ptr.p_proc = p; /* store the proc handle */
+
+ KNOTE_ATTACH(&p->p_klist, kn);
+
+ proc_klist_unlock();
+
+ proc_rele(p);
+
+ return (0);
+}
+
+/*
+ * The knote may be attached to a different process, which may exit,
+ * leaving nothing for the knote to be attached to. In that case,
+ * the pointer to the process will have already been nulled out.
+ */
+static void
+filt_procdetach(struct knote *kn)
+{
+ struct proc *p;
+
+ proc_klist_lock();
+
+ p = kn->kn_ptr.p_proc;
+ if (p != PROC_NULL) {
+ kn->kn_ptr.p_proc = PROC_NULL;
+ KNOTE_DETACH(&p->p_klist, kn);
+ }
+
+ proc_klist_unlock();
+}
+
+static int
+filt_proc(struct knote *kn, long hint)
+{
+ /* hint is 0 when called from above */
+ if (hint != 0) {
+ u_int event;
+
+ /* ALWAYS CALLED WITH proc_klist_lock when (hint != 0) */
+
+ /*
+ * mask off extra data
+ */
+ event = (u_int)hint & NOTE_PCTRLMASK;
+
+ /*
+ * if the user is interested in this event, record it.
+ */
+ if (kn->kn_sfflags & event)
+ kn->kn_fflags |= event;
+
+ if (event == NOTE_REAP || (event == NOTE_EXIT && !(kn->kn_sfflags & NOTE_REAP))) {
+ kn->kn_flags |= (EV_EOF | EV_ONESHOT);
+ }
+ if ((event == NOTE_EXIT) && ((kn->kn_sfflags & NOTE_EXITSTATUS) != 0)) {
+ kn->kn_fflags |= NOTE_EXITSTATUS;
+ kn->kn_data = (hint & NOTE_PDATAMASK);
+ }
+ if ((event == NOTE_RESOURCEEND) && ((kn->kn_sfflags & NOTE_RESOURCEEND) != 0)) {
+ kn->kn_fflags |= NOTE_RESOURCEEND;
+ kn->kn_data = (hint & NOTE_PDATAMASK);
+ }
+#if CONFIG_EMBEDDED
+ /* If the event is one of the APPSTATE events,remove the rest */
+ if (((event & NOTE_APPALLSTATES) != 0) && ((kn->kn_sfflags & NOTE_APPALLSTATES) != 0)) {
+ /* only one state at a time */
+ kn->kn_fflags &= ~NOTE_APPALLSTATES;
+ kn->kn_fflags |= event;
+ }
+#endif /* CONFIG_EMBEDDED */
+ }
+
+ /* atomic check, no locking need when called from above */
+ return (kn->kn_fflags != 0);
+}
+
+#if VM_PRESSURE_EVENTS
+/*
+ * Virtual memory kevents
+ *
+ * author: Matt Jacobson [matthew_jacobson@apple.com]
+ */
+
+static int
+filt_vmattach(struct knote *kn)
+{
+ /*
+ * The note will be cleared once the information has been flushed to the client.
+ * If there is still pressure, we will be re-alerted.
+ */
+ kn->kn_flags |= EV_CLEAR;
+
+ return vm_knote_register(kn);
+}
+
+static void
+filt_vmdetach(struct knote *kn)
+{
+ vm_knote_unregister(kn);
+}
+
+static int
+filt_vm(struct knote *kn, long hint)
+{
+ /* hint == 0 means this is just an alive? check (always true) */
+ if (hint != 0) {
+ const pid_t pid = (pid_t)hint;
+ if ((kn->kn_sfflags & NOTE_VM_PRESSURE) && (kn->kn_kq->kq_p->p_pid == pid)) {
+ kn->kn_fflags |= NOTE_VM_PRESSURE;
+ }
+ }
+
+ return (kn->kn_fflags != 0);
+}
+#endif /* VM_PRESSURE_EVENTS */
+
+/*
+ * filt_timervalidate - process data from user
+ *
+ * Converts to either interval or deadline format.
+ *
+ * The saved-data field in the knote contains the
+ * time value. The saved filter-flags indicates
+ * the unit of measurement.
+ *
+ * After validation, either the saved-data field
+ * contains the interval in absolute time, or ext[0]
+ * contains the expected deadline. If that deadline
+ * is in the past, ext[0] is 0.
+ *
+ * Returns EINVAL for unrecognized units of time.
+ *
+ * Timer filter lock is held.
+ *
+ */
+static int
+filt_timervalidate(struct knote *kn)
+{
+ uint64_t multiplier;
+ uint64_t raw;
+
+ switch (kn->kn_sfflags & (NOTE_SECONDS|NOTE_USECONDS|NOTE_NSECONDS)) {
+ case NOTE_SECONDS:
+ multiplier = NSEC_PER_SEC;
+ break;
+ case NOTE_USECONDS:
+ multiplier = NSEC_PER_USEC;
+ break;
+ case NOTE_NSECONDS:
+ multiplier = 1;
+ break;
+ case 0: /* milliseconds (default) */
+ multiplier = NSEC_PER_SEC / 1000;
+ break;
+ default:
+ return EINVAL;
+ }
+
+ nanoseconds_to_absolutetime((uint64_t)kn->kn_sdata * multiplier, &raw);
+
+ kn->kn_ext[0] = 0;
+ kn->kn_sdata = 0;
+
+ if (kn->kn_sfflags & NOTE_ABSOLUTE) {
+ clock_sec_t seconds;
+ clock_nsec_t nanoseconds;
+ uint64_t now;
+
+ clock_get_calendar_nanotime(&seconds, &nanoseconds);
+ nanoseconds_to_absolutetime((uint64_t)seconds * NSEC_PER_SEC +
+ nanoseconds, &now);
+
+ if (raw < now) {
+ /* time has already passed */
+ kn->kn_ext[0] = 0;
+ } else {
+ raw -= now;
+ clock_absolutetime_interval_to_deadline(raw,
+ &kn->kn_ext[0]);
+ }
+ } else {
+ kn->kn_sdata = raw;
+ }
+
+ return 0;
+}
+
+/*
+ * filt_timerupdate - compute the next deadline
+ *
+ * Repeating timers store their interval in kn_sdata. Absolute
+ * timers have already calculated the deadline, stored in ext[0].
+ *
+ * On return, the next deadline (or zero if no deadline is needed)
+ * is stored in kn_ext[0].
+ *
+ * Timer filter lock is held.
+ */
+static void
+filt_timerupdate(struct knote *kn)
+{
+ /* if there's no interval, deadline is just in kn_ext[0] */
+ if (kn->kn_sdata == 0)
+ return;
+
+ /* if timer hasn't fired before, fire in interval nsecs */
+ if (kn->kn_ext[0] == 0) {
+ clock_absolutetime_interval_to_deadline(kn->kn_sdata,
+ &kn->kn_ext[0]);
+ } else {
+ /*
+ * If timer has fired before, schedule the next pop
+ * relative to the last intended deadline.
+ *
+ * We could check for whether the deadline has expired,
+ * but the thread call layer can handle that.
+ */
+ kn->kn_ext[0] += kn->kn_sdata;
+ }
+}
+
+/*
+ * filt_timerexpire - the timer callout routine
+ *
+ * Just propagate the timer event into the knote
+ * filter routine (by going through the knote
+ * synchronization point). Pass a hint to
+ * indicate this is a real event, not just a
+ * query from above.
+ */
+static void
+filt_timerexpire(void *knx, __unused void *spare)
+{
+ struct klist timer_list;
+ struct knote *kn = knx;
+
+ filt_timerlock();
+
+ kn->kn_hookid &= ~TIMER_RUNNING;
+
+ /* no "object" for timers, so fake a list */
+ SLIST_INIT(&timer_list);
+ SLIST_INSERT_HEAD(&timer_list, kn, kn_selnext);
+ KNOTE(&timer_list, 1);
+
+ /* if someone is waiting for timer to pop */
+ if (kn->kn_hookid & TIMER_CANCELWAIT) {
+ struct kqueue *kq = kn->kn_kq;
+ wait_queue_wakeup_all((wait_queue_t)kq->kq_wqs, &kn->kn_hook,
+ THREAD_AWAKENED);
+ }
+
+ filt_timerunlock();
+}
+
+/*
+ * Cancel a running timer (or wait for the pop).
+ * Timer filter lock is held.
+ */
+static void
+filt_timercancel(struct knote *kn)
+{
+ struct kqueue *kq = kn->kn_kq;
+ thread_call_t callout = kn->kn_hook;
+ boolean_t cancelled;
+
+ if (kn->kn_hookid & TIMER_RUNNING) {
+ /* cancel the callout if we can */
+ cancelled = thread_call_cancel(callout);
+ if (cancelled) {
+ kn->kn_hookid &= ~TIMER_RUNNING;
+ } else {
+ /* we have to wait for the expire routine. */
+ kn->kn_hookid |= TIMER_CANCELWAIT;
+ wait_queue_assert_wait((wait_queue_t)kq->kq_wqs,
+ &kn->kn_hook, THREAD_UNINT, 0);
+ filt_timerunlock();
+ thread_block(THREAD_CONTINUE_NULL);
+ filt_timerlock();
+ assert((kn->kn_hookid & TIMER_RUNNING) == 0);
+ }
+ }
+}
+
+/*
+ * Allocate a thread call for the knote's lifetime, and kick off the timer.
+ */
+static int
+filt_timerattach(struct knote *kn)
+{
+ thread_call_t callout;
+ int error;
+
+ callout = thread_call_allocate(filt_timerexpire, kn);
+ if (NULL == callout)
+ return (ENOMEM);
+
+ filt_timerlock();
+ error = filt_timervalidate(kn);
+ if (error) {
+ filt_timerunlock();
+ return (error);
+ }
+
+ kn->kn_hook = (void*)callout;
+ kn->kn_hookid = 0;
+
+ /* absolute=EV_ONESHOT */
+ if (kn->kn_sfflags & NOTE_ABSOLUTE)
+ kn->kn_flags |= EV_ONESHOT;
+
+ filt_timerupdate(kn);
+ if (kn->kn_ext[0]) {
+ kn->kn_flags |= EV_CLEAR;
+ thread_call_enter_delayed(callout, kn->kn_ext[0]);
+ kn->kn_hookid |= TIMER_RUNNING;
+ } else {
+ /* fake immediate */
+ kn->kn_data = 1;
+ }
+
+ filt_timerunlock();
+ return (0);
+}
+
+/*
+ * Shut down the timer if it's running, and free the callout.
+ */
+static void
+filt_timerdetach(struct knote *kn)
+{
+ thread_call_t callout;
+
+ filt_timerlock();
+
+ callout = (thread_call_t)kn->kn_hook;
+ filt_timercancel(kn);
+
+ filt_timerunlock();
+
+ thread_call_free(callout);
+}
+
+
+
+static int
+filt_timer(struct knote *kn, long hint)
+{
+ int result;
+
+ if (hint) {
+ /* real timer pop -- timer lock held by filt_timerexpire */
+
+ kn->kn_data++;
+
+ if (((kn->kn_hookid & TIMER_CANCELWAIT) == 0) &&
+ ((kn->kn_flags & EV_ONESHOT) == 0)) {
+
+ /* evaluate next time to fire */
+ filt_timerupdate(kn);
+
+ if (kn->kn_ext[0]) {
+ /* keep the callout and re-arm */
+ thread_call_enter_delayed(kn->kn_hook,
+ kn->kn_ext[0]);
+ kn->kn_hookid |= TIMER_RUNNING;
+ }
+ }
+
+ return 1;
+ }
+
+ /* user-query */
+ filt_timerlock();
+
+ result = (kn->kn_data != 0);
+
+ filt_timerunlock();
+ return result;
+}
+
+
+/*
+ * filt_timertouch - update knote with new user input
+ *
+ * Cancel and restart the timer based on new user data. When
+ * the user picks up a knote, clear the count of how many timer
+ * pops have gone off (in kn_data).
+ */
+static void
+filt_timertouch(struct knote *kn, struct kevent64_s *kev, long type)
+{
+ int error;
+ filt_timerlock();
+
+ switch (type) {
+ case EVENT_REGISTER:
+ /* cancel current call */
+ filt_timercancel(kn);
+
+ /* recalculate deadline */
+ kn->kn_sdata = kev->data;
+ kn->kn_sfflags = kev->fflags;
+
+ error = filt_timervalidate(kn);
+ if (error) {
+ /* no way to report error, so mark it in the knote */
+ kn->kn_flags |= EV_ERROR;
+ kn->kn_data = error;
+ break;
+ }
+
+ /* start timer if necessary */
+ filt_timerupdate(kn);
+ if (kn->kn_ext[0]) {
+ thread_call_enter_delayed(kn->kn_hook, kn->kn_ext[0]);
+ kn->kn_hookid |= TIMER_RUNNING;
+ } else {
+ /* pretend the timer has fired */
+ kn->kn_data = 1;
+ }
+
+ break;
+
+ case EVENT_PROCESS:
+ /* reset the timer pop count in kn_data */
+ *kev = kn->kn_kevent;
+ kev->ext[0] = 0;
+ kn->kn_data = 0;
+ if (kn->kn_flags & EV_CLEAR)
+ kn->kn_fflags = 0;
+ break;
+ default:
+ panic("filt_timertouch() - invalid type (%ld)", type);
+ break;
+ }
+
+ filt_timerunlock();
+}
+
+static void
+filt_timerlock(void)
+{
+ lck_mtx_lock(&_filt_timerlock);
+}
+
+static void
+filt_timerunlock(void)
+{
+ lck_mtx_unlock(&_filt_timerlock);
+}
+
+static int
+filt_userattach(struct knote *kn)
+{
+ /* EVFILT_USER knotes are not attached to anything in the kernel */
+ kn->kn_hook = NULL;
+ if (kn->kn_fflags & NOTE_TRIGGER) {
+ kn->kn_hookid = 1;
+ } else {
+ kn->kn_hookid = 0;
+ }
+ return 0;
+}
+
+static void
+filt_userdetach(__unused struct knote *kn)
+{
+ /* EVFILT_USER knotes are not attached to anything in the kernel */
+}
+
+static int
+filt_user(struct knote *kn, __unused long hint)
+{
+ return kn->kn_hookid;
+}
+
+static void
+filt_usertouch(struct knote *kn, struct kevent64_s *kev, long type)
+{
+ uint32_t ffctrl;
+ switch (type) {
+ case EVENT_REGISTER:
+ if (kev->fflags & NOTE_TRIGGER) {
+ kn->kn_hookid = 1;
+ }
+
+ ffctrl = kev->fflags & NOTE_FFCTRLMASK;
+ kev->fflags &= NOTE_FFLAGSMASK;
+ switch (ffctrl) {
+ case NOTE_FFNOP:
+ break;
+ case NOTE_FFAND:
+ OSBitAndAtomic(kev->fflags, &kn->kn_sfflags);
+ break;
+ case NOTE_FFOR:
+ OSBitOrAtomic(kev->fflags, &kn->kn_sfflags);
+ break;
+ case NOTE_FFCOPY:
+ kn->kn_sfflags = kev->fflags;
+ break;
+ }
+ kn->kn_sdata = kev->data;
+ break;
+ case EVENT_PROCESS:
+ *kev = kn->kn_kevent;
+ kev->fflags = (volatile UInt32)kn->kn_sfflags;
+ kev->data = kn->kn_sdata;
+ if (kn->kn_flags & EV_CLEAR) {
+ kn->kn_hookid = 0;
+ kn->kn_data = 0;
+ kn->kn_fflags = 0;
+ }
+ break;
+ default:
+ panic("filt_usertouch() - invalid type (%ld)", type);
+ break;
+ }
+}
+
+/*
+ * JMM - placeholder for not-yet-implemented filters
+ */
+static int
+filt_badattach(__unused struct knote *kn)
+{
+ return(ENOTSUP);
+}
+
+
+struct kqueue *
+kqueue_alloc(struct proc *p)
+{
+ struct filedesc *fdp = p->p_fd;
+ struct kqueue *kq;
+
+ MALLOC_ZONE(kq, struct kqueue *, sizeof(struct kqueue), M_KQUEUE, M_WAITOK);
+ if (kq != NULL) {
+ wait_queue_set_t wqs;
+
+ wqs = wait_queue_set_alloc(SYNC_POLICY_FIFO | SYNC_POLICY_PREPOST);
+ if (wqs != NULL) {
+ bzero(kq, sizeof(struct kqueue));
+ lck_spin_init(&kq->kq_lock, kq_lck_grp, kq_lck_attr);
+ TAILQ_INIT(&kq->kq_head);
+ kq->kq_wqs = wqs;
+ kq->kq_p = p;
+ } else {
+ FREE_ZONE(kq, sizeof(struct kqueue), M_KQUEUE);
+ }
+ }
+
+ if (fdp->fd_knlistsize < 0) {
+ proc_fdlock(p);
+ if (fdp->fd_knlistsize < 0)
+ fdp->fd_knlistsize = 0; /* this process has had a kq */
+ proc_fdunlock(p);
+ }
+
+ return kq;
+}
+
+
+/*
+ * kqueue_dealloc - detach all knotes from a kqueue and free it
+ *
+ * We walk each list looking for knotes referencing this
+ * this kqueue. If we find one, we try to drop it. But
+ * if we fail to get a drop reference, that will wait
+ * until it is dropped. So, we can just restart again
+ * safe in the assumption that the list will eventually
+ * not contain any more references to this kqueue (either
+ * we dropped them all, or someone else did).
+ *
+ * Assumes no new events are being added to the kqueue.
+ * Nothing locked on entry or exit.
+ */
+void
+kqueue_dealloc(struct kqueue *kq)
+{
+ struct proc *p = kq->kq_p;
+ struct filedesc *fdp = p->p_fd;
+ struct knote *kn;
+ int i;
+
+ proc_fdlock(p);
+ for (i = 0; i < fdp->fd_knlistsize; i++) {
+ kn = SLIST_FIRST(&fdp->fd_knlist[i]);
+ while (kn != NULL) {
+ if (kq == kn->kn_kq) {
+ kqlock(kq);
+ proc_fdunlock(p);
+ /* drop it ourselves or wait */
+ if (kqlock2knotedrop(kq, kn)) {
+ kn->kn_fop->f_detach(kn);
+ knote_drop(kn, p);
+ }
+ proc_fdlock(p);
+ /* start over at beginning of list */
+ kn = SLIST_FIRST(&fdp->fd_knlist[i]);
+ continue;
+ }
+ kn = SLIST_NEXT(kn, kn_link);
+ }
+ }
+ if (fdp->fd_knhashmask != 0) {
+ for (i = 0; i < (int)fdp->fd_knhashmask + 1; i++) {
+ kn = SLIST_FIRST(&fdp->fd_knhash[i]);
+ while (kn != NULL) {
+ if (kq == kn->kn_kq) {
+ kqlock(kq);
+ proc_fdunlock(p);
+ /* drop it ourselves or wait */
+ if (kqlock2knotedrop(kq, kn)) {
+ kn->kn_fop->f_detach(kn);
+ knote_drop(kn, p);
+ }
+ proc_fdlock(p);
+ /* start over at beginning of list */
+ kn = SLIST_FIRST(&fdp->fd_knhash[i]);
+ continue;
+ }
+ kn = SLIST_NEXT(kn, kn_link);
+ }
+ }
+ }
+ proc_fdunlock(p);
+
+ /*
+ * before freeing the wait queue set for this kqueue,
+ * make sure it is unlinked from all its containing (select) sets.
+ */
+ wait_queue_unlink_all((wait_queue_t)kq->kq_wqs);
+ wait_queue_set_free(kq->kq_wqs);
+ lck_spin_destroy(&kq->kq_lock, kq_lck_grp);
+ FREE_ZONE(kq, sizeof(struct kqueue), M_KQUEUE);
+}
+
+int
+kqueue(struct proc *p, __unused struct kqueue_args *uap, int32_t *retval)
+{
+ struct kqueue *kq;
+ struct fileproc *fp;
+ int fd, error;
+
+ error = falloc(p, &fp, &fd, vfs_context_current());
+ if (error) {
+ return (error);
+ }
+
+ kq = kqueue_alloc(p);
+ if (kq == NULL) {
+ fp_free(p, fd, fp);
+ return (ENOMEM);
+ }
+
+ fp->f_flag = FREAD | FWRITE;
+ fp->f_type = DTYPE_KQUEUE;
+ fp->f_ops = &kqueueops;
+ fp->f_data = (caddr_t)kq;
+
+ proc_fdlock(p);
+ procfdtbl_releasefd(p, fd, NULL);
+ fp_drop(p, fd, fp, 1);
+ proc_fdunlock(p);
+
+ *retval = fd;
+ return (error);
+}
+
+static int
+kevent_copyin(user_addr_t *addrp, struct kevent64_s *kevp, struct proc *p, int iskev64)
+{
+ int advance;
+ int error;
+
+ if (iskev64) {
+ advance = sizeof(struct kevent64_s);
+ error = copyin(*addrp, (caddr_t)kevp, advance);
+ } else if (IS_64BIT_PROCESS(p)) {
+ struct user64_kevent kev64;
+ bzero(kevp, sizeof(struct kevent64_s));
+
+ advance = sizeof(kev64);
+ error = copyin(*addrp, (caddr_t)&kev64, advance);
+ if (error)
+ return error;
+ kevp->ident = kev64.ident;
+ kevp->filter = kev64.filter;
+ kevp->flags = kev64.flags;
+ kevp->fflags = kev64.fflags;
+ kevp->data = kev64.data;
+ kevp->udata = kev64.udata;
+ } else {
+ struct user32_kevent kev32;
+ bzero(kevp, sizeof(struct kevent64_s));
+
+ advance = sizeof(kev32);
+ error = copyin(*addrp, (caddr_t)&kev32, advance);
+ if (error)
+ return error;
+ kevp->ident = (uintptr_t)kev32.ident;
+ kevp->filter = kev32.filter;
+ kevp->flags = kev32.flags;
+ kevp->fflags = kev32.fflags;
+ kevp->data = (intptr_t)kev32.data;
+ kevp->udata = CAST_USER_ADDR_T(kev32.udata);
+ }
+ if (!error)
+ *addrp += advance;
+ return error;
+}
+
+static int
+kevent_copyout(struct kevent64_s *kevp, user_addr_t *addrp, struct proc *p, int iskev64)
+{
+ int advance;
+ int error;
+
+ if (iskev64) {
+ advance = sizeof(struct kevent64_s);
+ error = copyout((caddr_t)kevp, *addrp, advance);
+ } else if (IS_64BIT_PROCESS(p)) {
+ struct user64_kevent kev64;
+
+ /*
+ * deal with the special case of a user-supplied
+ * value of (uintptr_t)-1.
+ */
+ kev64.ident = (kevp->ident == (uintptr_t)-1) ?
+ (uint64_t)-1LL : (uint64_t)kevp->ident;
+
+ kev64.filter = kevp->filter;
+ kev64.flags = kevp->flags;
+ kev64.fflags = kevp->fflags;
+ kev64.data = (int64_t) kevp->data;
+ kev64.udata = kevp->udata;
+ advance = sizeof(kev64);
+ error = copyout((caddr_t)&kev64, *addrp, advance);
+ } else {
+ struct user32_kevent kev32;
+
+ kev32.ident = (uint32_t)kevp->ident;
+ kev32.filter = kevp->filter;
+ kev32.flags = kevp->flags;
+ kev32.fflags = kevp->fflags;
+ kev32.data = (int32_t)kevp->data;
+ kev32.udata = kevp->udata;
+ advance = sizeof(kev32);
+ error = copyout((caddr_t)&kev32, *addrp, advance);
+ }
+ if (!error)
+ *addrp += advance;
+ return error;
+}
+
+/*
+ * kevent_continue - continue a kevent syscall after blocking
+ *
+ * assume we inherit a use count on the kq fileglob.
+ */
+
+static void
+kevent_continue(__unused struct kqueue *kq, void *data, int error)
+{
+ struct _kevent *cont_args;
+ struct fileproc *fp;
+ int32_t *retval;
+ int noutputs;
+ int fd;
+ struct proc *p = current_proc();
+
+ cont_args = (struct _kevent *)data;
+ noutputs = cont_args->eventout;
+ retval = cont_args->retval;
+ fd = cont_args->fd;
+ fp = cont_args->fp;
+
+ fp_drop(p, fd, fp, 0);
+
+ /* don't restart after signals... */
+ if (error == ERESTART)
+ error = EINTR;
+ else if (error == EWOULDBLOCK)
+ error = 0;
+ if (error == 0)
+ *retval = noutputs;
+ unix_syscall_return(error);
+}
+
+/*
+ * kevent - [syscall] register and wait for kernel events
+ *
+ */
+int
+kevent(struct proc *p, struct kevent_args *uap, int32_t *retval)
+{
+ return kevent_internal(p,
+ 0,
+ uap->changelist,
+ uap->nchanges,
+ uap->eventlist,
+ uap->nevents,
+ uap->fd,
+ uap->timeout,
+ 0, /* no flags from old kevent() call */
+ retval);
+}
+
+int
+kevent64(struct proc *p, struct kevent64_args *uap, int32_t *retval)
+{
+ return kevent_internal(p,
+ 1,
+ uap->changelist,
+ uap->nchanges,
+ uap->eventlist,
+ uap->nevents,
+ uap->fd,
+ uap->timeout,
+ uap->flags,
+ retval);
+}
+
+static int
+kevent_internal(struct proc *p, int iskev64, user_addr_t changelist,
+ int nchanges, user_addr_t ueventlist, int nevents, int fd,
+ user_addr_t utimeout, __unused unsigned int flags,
+ int32_t *retval)
+{
+ struct _kevent *cont_args;
+ uthread_t ut;
+ struct kqueue *kq;
+ struct fileproc *fp;
+ struct kevent64_s kev;
+ int error, noutputs;
+ struct timeval atv;
+
+ /* convert timeout to absolute - if we have one */
+ if (utimeout != USER_ADDR_NULL) {
+ struct timeval rtv;
+ if (IS_64BIT_PROCESS(p)) {
+ struct user64_timespec ts;
+ error = copyin(utimeout, &ts, sizeof(ts));
+ if ((ts.tv_sec & 0xFFFFFFFF00000000ull) != 0)
+ error = EINVAL;
+ else
+ TIMESPEC_TO_TIMEVAL(&rtv, &ts);
+ } else {
+ struct user32_timespec ts;
+ error = copyin(utimeout, &ts, sizeof(ts));
+ TIMESPEC_TO_TIMEVAL(&rtv, &ts);
+ }
+ if (error)
+ return error;
+ if (itimerfix(&rtv))
+ return EINVAL;
+ getmicrouptime(&atv);
+ timevaladd(&atv, &rtv);
+ } else {
+ atv.tv_sec = 0;
+ atv.tv_usec = 0;
+ }
+
+ /* get a usecount for the kq itself */
+ if ((error = fp_getfkq(p, fd, &fp, &kq)) != 0)
+ return(error);
+
+ /* each kq should only be used for events of one type */
+ kqlock(kq);
+ if (kq->kq_state & (KQ_KEV32 | KQ_KEV64)) {
+ if (((iskev64 && (kq->kq_state & KQ_KEV32)) ||
+ (!iskev64 && (kq->kq_state & KQ_KEV64)))) {
+ error = EINVAL;
+ kqunlock(kq);
+ goto errorout;
+ }
+ } else {
+ kq->kq_state |= (iskev64 ? KQ_KEV64 : KQ_KEV32);
+ }
+ kqunlock(kq);
+
+ /* register all the change requests the user provided... */
+ noutputs = 0;
+ while (nchanges > 0 && error == 0) {
+ error = kevent_copyin(&changelist, &kev, p, iskev64);
+ if (error)
+ break;
+
+ kev.flags &= ~EV_SYSFLAGS;
+ error = kevent_register(kq, &kev, p);
+ if ((error || (kev.flags & EV_RECEIPT)) && nevents > 0) {
+ kev.flags = EV_ERROR;
+ kev.data = error;
+ error = kevent_copyout(&kev, &ueventlist, p, iskev64);
+ if (error == 0) {
+ nevents--;
+ noutputs++;
+ }
+ }
+ nchanges--;
+ }
+
+ /* store the continuation/completion data in the uthread */
+ ut = (uthread_t)get_bsdthread_info(current_thread());
+ cont_args = &ut->uu_kevent.ss_kevent;
+ cont_args->fp = fp;
+ cont_args->fd = fd;
+ cont_args->retval = retval;
+ cont_args->eventlist = ueventlist;
+ cont_args->eventcount = nevents;
+ cont_args->eventout = noutputs;
+ cont_args->eventsize = iskev64;
+
+ if (nevents > 0 && noutputs == 0 && error == 0)
+ error = kqueue_scan(kq, kevent_callback,
+ kevent_continue, cont_args,
+ &atv, p);
+ kevent_continue(kq, cont_args, error);
+
+errorout:
+ fp_drop(p, fd, fp, 0);
+ return error;
+}
+
+
+/*
+ * kevent_callback - callback for each individual event
+ *
+ * called with nothing locked
+ * caller holds a reference on the kqueue
+ */
+
+static int
+kevent_callback(__unused struct kqueue *kq, struct kevent64_s *kevp,
+ void *data)
+{
+ struct _kevent *cont_args;
+ int error;
+ int iskev64;
+
+ cont_args = (struct _kevent *)data;
+ assert(cont_args->eventout < cont_args->eventcount);
+
+ iskev64 = cont_args->eventsize;
+
+ /*
+ * Copy out the appropriate amount of event data for this user.
+ */
+ error = kevent_copyout(kevp, &cont_args->eventlist, current_proc(), iskev64);
+
+ /*
+ * If there isn't space for additional events, return
+ * a harmless error to stop the processing here
+ */
+ if (error == 0 && ++cont_args->eventout == cont_args->eventcount)
+ error = EWOULDBLOCK;
+ return error;
+}
+
+/*
+ * kevent_description - format a description of a kevent for diagnostic output
+ *
+ * called with a 128-byte string buffer
+ */
+
+char *
+kevent_description(struct kevent64_s *kevp, char *s, size_t n)
+{
+ snprintf(s, n,
+ "kevent="
+ "{.ident=%#llx, .filter=%d, .flags=%#x, .fflags=%#x, .data=%#llx, .udata=%#llx, .ext[0]=%#llx, .ext[1]=%#llx}",
+ kevp->ident,
+ kevp->filter,
+ kevp->flags,
+ kevp->fflags,
+ kevp->data,
+ kevp->udata,
+ kevp->ext[0],
+ kevp->ext[1]);
+ return s;
+}
+
+/*
+ * kevent_register - add a new event to a kqueue
+ *
+ * Creates a mapping between the event source and
+ * the kqueue via a knote data structure.
+ *
+ * Because many/most the event sources are file
+ * descriptor related, the knote is linked off
+ * the filedescriptor table for quick access.
+ *
+ * called with nothing locked
+ * caller holds a reference on the kqueue
+ */
+
+int
+kevent_register(struct kqueue *kq, struct kevent64_s *kev, __unused struct proc *ctxp)
+{
+ struct proc *p = kq->kq_p;
+ struct filedesc *fdp = p->p_fd;
+ struct filterops *fops;
+ struct fileproc *fp = NULL;
+ struct knote *kn = NULL;
+ int error = 0;
+
+ if (kev->filter < 0) {
+ if (kev->filter + EVFILT_SYSCOUNT < 0)
+ return (EINVAL);
+ fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
+ } else {
+ /*
+ * XXX
+ * filter attach routine is responsible for insuring that
+ * the identifier can be attached to it.
+ */
+ printf("unknown filter: %d\n", kev->filter);
+ return (EINVAL);
+ }
+
+ restart:
+ /* this iocount needs to be dropped if it is not registered */
+ proc_fdlock(p);
+ if (fops->f_isfd && (error = fp_lookup(p, kev->ident, &fp, 1)) != 0) {
+ proc_fdunlock(p);
+ return(error);
+ }
+
+ if (fops->f_isfd) {
+ /* fd-based knotes are linked off the fd table */
+ if (kev->ident < (u_int)fdp->fd_knlistsize) {
+ SLIST_FOREACH(kn, &fdp->fd_knlist[kev->ident], kn_link)
+ if (kq == kn->kn_kq &&
+ kev->filter == kn->kn_filter)
+ break;
+ }
+ } else {
+ /* hash non-fd knotes here too */
+ if (fdp->fd_knhashmask != 0) {
+ struct klist *list;
+
+ list = &fdp->fd_knhash[
+ KN_HASH((u_long)kev->ident, fdp->fd_knhashmask)];
+ SLIST_FOREACH(kn, list, kn_link)
+ if (kev->ident == kn->kn_id &&
+ kq == kn->kn_kq &&
+ kev->filter == kn->kn_filter)
+ break;
+ }
+ }
+
+ /*
+ * kn now contains the matching knote, or NULL if no match
+ */
+ if (kn == NULL) {
+ if ((kev->flags & (EV_ADD|EV_DELETE)) == EV_ADD) {
+ kn = knote_alloc();
+ if (kn == NULL) {
+ proc_fdunlock(p);
+ error = ENOMEM;
+ goto done;
+ }
+ kn->kn_fp = fp;
+ kn->kn_kq = kq;
+ kn->kn_tq = &kq->kq_head;
+ kn->kn_fop = fops;
+ kn->kn_sfflags = kev->fflags;
+ kn->kn_sdata = kev->data;
+ kev->fflags = 0;
+ kev->data = 0;
+ kn->kn_kevent = *kev;
+ kn->kn_inuse = 1; /* for f_attach() */
+ kn->kn_status = KN_ATTACHING;
+
+ /* before anyone can find it */
+ if (kev->flags & EV_DISABLE)
+ kn->kn_status |= KN_DISABLED;
+
+ error = knote_fdpattach(kn, fdp, p);
+ proc_fdunlock(p);
+
+ if (error) {
+ knote_free(kn);
+ goto done;
+ }
+
+ /*
+ * apply reference count to knote structure, and
+ * do not release it at the end of this routine.
+ */
+ fp = NULL;
+
+ error = fops->f_attach(kn);
+
+ kqlock(kq);
+
+ if (error != 0) {
+ /*
+ * Failed to attach correctly, so drop.
+ * All other possible users/droppers
+ * have deferred to us.
+ */
+ kn->kn_status |= KN_DROPPING;
+ kqunlock(kq);
+ knote_drop(kn, p);
+ goto done;
+ } else if (kn->kn_status & KN_DROPPING) {
+ /*
+ * Attach succeeded, but someone else
+ * deferred their drop - now we have
+ * to do it for them (after detaching).
+ */
+ kqunlock(kq);
+ kn->kn_fop->f_detach(kn);
+ knote_drop(kn, p);
+ goto done;
+ }
+ kn->kn_status &= ~KN_ATTACHING;
+ kqunlock(kq);
+ } else {
+ proc_fdunlock(p);
+ error = ENOENT;
+ goto done;
+ }
+ } else {
+ /* existing knote - get kqueue lock */
+ kqlock(kq);
+ proc_fdunlock(p);
+
+ if (kev->flags & EV_DELETE) {
+ knote_dequeue(kn);
+ kn->kn_status |= KN_DISABLED;
+ if (kqlock2knotedrop(kq, kn)) {
+ kn->kn_fop->f_detach(kn);
+ knote_drop(kn, p);
+ }
+ goto done;
+ }
+
+ /* update status flags for existing knote */
+ if (kev->flags & EV_DISABLE) {
+ knote_dequeue(kn);
+ kn->kn_status |= KN_DISABLED;
+ } else if (kev->flags & EV_ENABLE) {
+ kn->kn_status &= ~KN_DISABLED;
+ if (kn->kn_status & KN_ACTIVE)
+ knote_enqueue(kn);
+ }
+
+ /*
+ * The user may change some filter values after the
+ * initial EV_ADD, but doing so will not reset any
+ * filter which have already been triggered.
+ */
+ kn->kn_kevent.udata = kev->udata;
+ if (fops->f_isfd || fops->f_touch == NULL) {
+ kn->kn_sfflags = kev->fflags;
+ kn->kn_sdata = kev->data;
+ }
+
+ /*
+ * If somebody is in the middle of dropping this
+ * knote - go find/insert a new one. But we have
+ * wait for this one to go away first. Attaches
+ * running in parallel may also drop/modify the
+ * knote. Wait for those to complete as well and
+ * then start over if we encounter one.
+ */
+ if (!kqlock2knoteusewait(kq, kn)) {
+ /* kqueue, proc_fdlock both unlocked */
+ goto restart;
+ }
+
+ /*
+ * Call touch routine to notify filter of changes
+ * in filter values.
+ */
+ if (!fops->f_isfd && fops->f_touch != NULL)
+ fops->f_touch(kn, kev, EVENT_REGISTER);
+ }
+ /* still have use ref on knote */
+
+ /*
+ * If the knote is not marked to always stay enqueued,
+ * invoke the filter routine to see if it should be
+ * enqueued now.
+ */
+ if ((kn->kn_status & KN_STAYQUEUED) == 0 && kn->kn_fop->f_event(kn, 0)) {
+ if (knoteuse2kqlock(kq, kn))
+ knote_activate(kn, 1);
+ kqunlock(kq);
+ } else {
+ knote_put(kn);
+ }
+
+done:
+ if (fp != NULL)
+ fp_drop(p, kev->ident, fp, 0);
+ return (error);
+}
+
+
+/*
+ * knote_process - process a triggered event
+ *
+ * Validate that it is really still a triggered event
+ * by calling the filter routines (if necessary). Hold
+ * a use reference on the knote to avoid it being detached.
+ * If it is still considered triggered, invoke the callback
+ * routine provided and move it to the provided inprocess
+ * queue.
+ *
+ * caller holds a reference on the kqueue.
+ * kqueue locked on entry and exit - but may be dropped
+ */
+static int
+knote_process(struct knote *kn,
+ kevent_callback_t callback,
+ void *data,
+ struct kqtailq *inprocessp,
+ struct proc *p)
+{
+ struct kqueue *kq = kn->kn_kq;
+ struct kevent64_s kev;
+ int touch;
+ int result;
+ int error;
+
+ /*
+ * Determine the kevent state we want to return.
+ *
+ * Some event states need to be revalidated before returning
+ * them, others we take the snapshot at the time the event
+ * was enqueued.
+ *
+ * Events with non-NULL f_touch operations must be touched.
+ * Triggered events must fill in kev for the callback.
+ *
+ * Convert our lock to a use-count and call the event's
+ * filter routine(s) to update.
+ */
+ if ((kn->kn_status & KN_DISABLED) != 0) {
+ result = 0;
+ touch = 0;
+ } else {
+ int revalidate;
+
+ result = 1;
+ revalidate = ((kn->kn_status & KN_STAYQUEUED) != 0 ||
+ (kn->kn_flags & EV_ONESHOT) == 0);
+ touch = (!kn->kn_fop->f_isfd && kn->kn_fop->f_touch != NULL);
+
+ if (revalidate || touch) {
+ if (revalidate)
+ knote_deactivate(kn);
+
+ /* call the filter/touch routines with just a ref */
+ if (kqlock2knoteuse(kq, kn)) {
+
+ /* if we have to revalidate, call the filter */
+ if (revalidate) {
+ result = kn->kn_fop->f_event(kn, 0);
+ }
+
+ /* capture the kevent data - using touch if specified */
+ if (result && touch) {
+ kn->kn_fop->f_touch(kn, &kev, EVENT_PROCESS);
+ }
+
+ /* convert back to a kqlock - bail if the knote went away */
+ if (!knoteuse2kqlock(kq, kn)) {
+ return EJUSTRETURN;
+ } else if (result) {
+ /* if revalidated as alive, make sure it's active */
+ if (!(kn->kn_status & KN_ACTIVE)) {
+ knote_activate(kn, 0);
+ }
+
+ /* capture all events that occurred during filter */
+ if (!touch) {
+ kev = kn->kn_kevent;
+ }
+
+ } else if ((kn->kn_status & KN_STAYQUEUED) == 0) {
+ /* was already dequeued, so just bail on this one */
+ return EJUSTRETURN;
+ }
+ } else {
+ return EJUSTRETURN;
+ }
+ } else {
+ kev = kn->kn_kevent;
+ }
+ }
+
+ /* move knote onto inprocess queue */
+ assert(kn->kn_tq == &kq->kq_head);
+ TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe);
+ kn->kn_tq = inprocessp;
+ TAILQ_INSERT_TAIL(inprocessp, kn, kn_tqe);
+
+ /*
+ * Determine how to dispatch the knote for future event handling.
+ * not-fired: just return (do not callout).
+ * One-shot: deactivate it.
+ * Clear: deactivate and clear the state.
+ * Dispatch: don't clear state, just deactivate it and mark it disabled.
+ * All others: just leave where they are.
+ */
+
+ if (result == 0) {
+ return EJUSTRETURN;
+ } else if ((kn->kn_flags & EV_ONESHOT) != 0) {
+ knote_deactivate(kn);
+ if (kqlock2knotedrop(kq, kn)) {
+ kn->kn_fop->f_detach(kn);
+ knote_drop(kn, p);
+ }
+ } else if ((kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) != 0) {
+ if ((kn->kn_flags & EV_DISPATCH) != 0) {
+ /* deactivate and disable all dispatch knotes */
+ knote_deactivate(kn);
+ kn->kn_status |= KN_DISABLED;
+ } else if (!touch || kn->kn_fflags == 0) {
+ /* only deactivate if nothing since the touch */
+ knote_deactivate(kn);
+ }
+ if (!touch && (kn->kn_flags & EV_CLEAR) != 0) {
+ /* manually clear non-touch knotes */
+ kn->kn_data = 0;
+ kn->kn_fflags = 0;
+ }
+ kqunlock(kq);
+ } else {
+ /*
+ * leave on inprocess queue. We'll
+ * move all the remaining ones back
+ * the kq queue and wakeup any
+ * waiters when we are done.
+ */
+ kqunlock(kq);
+ }
+
+ /* callback to handle each event as we find it */
+ error = (callback)(kq, &kev, data);
+
+ kqlock(kq);
+ return error;
+}
+
+/*
+ * Return 0 to indicate that processing should proceed,
+ * -1 if there is nothing to process.
projects / apple / xnu.git / blobdiff