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gems-kernel/source/THIRDPARTY/xnu/bsd/kern/kern_event.c

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add darwin/xnu functionality
2024-06-03 11:29:39 -05:00
/*
* Copyright (c) 2000-2021 Apple Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @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 <machine/atomic.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/syscall.h> // SYS_* constants
#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 <sys/codesign.h>
#include <sys/pthread_shims.h>
#include <sys/kdebug.h>
#include <os/base.h>
#include <pexpert/pexpert.h>
#include <kern/thread_group.h>
#include <kern/locks.h>
#include <kern/clock.h>
#include <kern/cpu_data.h>
#include <kern/policy_internal.h>
#include <kern/thread_call.h>
#include <kern/sched_prim.h>
#include <kern/waitq.h>
#include <kern/zalloc.h>
#include <kern/kalloc.h>
#include <kern/assert.h>
#include <kern/ast.h>
#include <kern/thread.h>
#include <kern/kcdata.h>
#include <kern/work_interval.h>
#include <pthread/priority_private.h>
#include <pthread/workqueue_syscalls.h>
#include <pthread/workqueue_internal.h>
#include <libkern/libkern.h>
#include <os/log.h>
#include "net/net_str_id.h"
#if SKYWALK && defined(XNU_TARGET_OS_OSX)
#include <skywalk/lib/net_filter_event.h>
extern bool net_check_compatible_alf(void);
#endif /* SKYWALK && XNU_TARGET_OS_OSX */
#include <mach/task.h>
#include <libkern/section_keywords.h>
#if CONFIG_MEMORYSTATUS
#include <sys/kern_memorystatus.h>
#endif
#if DEVELOPMENT || DEBUG
#define KEVENT_PANIC_ON_WORKLOOP_OWNERSHIP_LEAK (1U << 0)
#define KEVENT_PANIC_ON_NON_ENQUEUED_PROCESS (1U << 1)
TUNABLE(uint32_t, kevent_debug_flags, "kevent_debug", 0);
#endif
static LCK_GRP_DECLARE(kq_lck_grp, "kqueue");
SECURITY_READ_ONLY_EARLY(vm_packing_params_t) kn_kq_packing_params =
VM_PACKING_PARAMS(KNOTE_KQ_PACKED);
extern mach_port_name_t ipc_entry_name_mask(mach_port_name_t name); /* osfmk/ipc/ipc_entry.h */
extern int cansignal(struct proc *, kauth_cred_t, struct proc *, int); /* bsd/kern/kern_sig.c */
#define KEV_EVTID(code) BSDDBG_CODE(DBG_BSD_KEVENT, (code))
static int kqueue_select(struct fileproc *fp, int which, void *wq_link_id,
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,
struct kevent_qos_s *kev);
static int kqueue_drain(struct fileproc *fp, vfs_context_t ctx);
static const struct fileops kqueueops = {
.fo_type = DTYPE_KQUEUE,
.fo_read = fo_no_read,
.fo_write = fo_no_write,
.fo_ioctl = fo_no_ioctl,
.fo_select = kqueue_select,
.fo_close = kqueue_close,
.fo_drain = kqueue_drain,
.fo_kqfilter = kqueue_kqfilter,
};
static inline int kevent_modern_copyout(struct kevent_qos_s *, user_addr_t *);
static int kevent_register_wait_prepare(struct knote *kn, struct kevent_qos_s *kev, int result);
static void kevent_register_wait_block(struct turnstile *ts, thread_t handoff_thread,
thread_continue_t cont, struct _kevent_register *cont_args) __dead2;
static void kevent_register_wait_return(struct _kevent_register *cont_args) __dead2;
static void kevent_register_wait_cleanup(struct knote *kn);
static struct kqtailq *kqueue_get_suppressed_queue(kqueue_t kq, struct knote *kn);
static void kqueue_threadreq_initiate(struct kqueue *kq, workq_threadreq_t, kq_index_t qos, int flags);
static void kqworkq_unbind(proc_t p, workq_threadreq_t);
static thread_qos_t kqworkq_unbind_locked(struct kqworkq *kqwq, workq_threadreq_t, thread_t thread);
static workq_threadreq_t kqworkq_get_request(struct kqworkq *kqwq, kq_index_t qos_index);
static void kqueue_update_iotier_override(kqueue_t kqu);
static void kqworkloop_unbind(struct kqworkloop *kwql);
enum kqwl_unbind_locked_mode {
KQWL_OVERRIDE_DROP_IMMEDIATELY,
KQWL_OVERRIDE_DROP_DELAYED,
};
static void kqworkloop_unbind_locked(struct kqworkloop *kwql, thread_t thread,
enum kqwl_unbind_locked_mode how);
static void kqworkloop_unbind_delayed_override_drop(thread_t thread);
static kq_index_t kqworkloop_override(struct kqworkloop *kqwl);
static void kqworkloop_set_overcommit(struct kqworkloop *kqwl);
enum {
KQWL_UTQ_NONE,
/*
* The wakeup qos is the qos of QUEUED knotes.
*
* This QoS is accounted for with the events override in the
* kqr_override_index field. It is raised each time a new knote is queued at
* a given QoS. The kqwl_wakeup_qos field is a superset of the non empty
* knote buckets and is recomputed after each event delivery.
*/
KQWL_UTQ_UPDATE_WAKEUP_QOS,
KQWL_UTQ_RECOMPUTE_WAKEUP_QOS,
KQWL_UTQ_UNBINDING, /* attempt to rebind */
KQWL_UTQ_PARKING,
/*
* The wakeup override is for suppressed knotes that have fired again at
* a higher QoS than the one for which they are suppressed already.
* This override is cleared when the knote suppressed list becomes empty.
*/
KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE,
KQWL_UTQ_RESET_WAKEUP_OVERRIDE,
/*
* The QoS is the maximum QoS of an event enqueued on this workloop in
* userland. It is copied from the only EVFILT_WORKLOOP knote with
* a NOTE_WL_THREAD_REQUEST bit set allowed on this workloop. If there is no
* such knote, this QoS is 0.
*/
KQWL_UTQ_SET_QOS_INDEX,
KQWL_UTQ_REDRIVE_EVENTS,
};
static void kqworkloop_update_threads_qos(struct kqworkloop *kqwl, int op, kq_index_t qos);
static int kqworkloop_end_processing(struct kqworkloop *kqwl, int flags, int kevent_flags);
static struct knote *knote_alloc(void);
static void knote_free(struct knote *kn);
static int kq_add_knote(struct kqueue *kq, struct knote *kn,
struct knote_lock_ctx *knlc, struct proc *p);
static struct knote *kq_find_knote_and_kq_lock(struct kqueue *kq,
struct kevent_qos_s *kev, bool is_fd, struct proc *p);
static void knote_activate(kqueue_t kqu, struct knote *kn, int result);
static void knote_dequeue(kqueue_t kqu, struct knote *kn);
static void knote_apply_touch(kqueue_t kqu, struct knote *kn,
struct kevent_qos_s *kev, int result);
static void knote_suppress(kqueue_t kqu, struct knote *kn);
static void knote_unsuppress(kqueue_t kqu, struct knote *kn);
static void knote_drop(kqueue_t kqu, struct knote *kn, struct knote_lock_ctx *knlc);
// both these functions may dequeue the knote and it is up to the caller
// to enqueue the knote back
static void knote_adjust_qos(struct kqueue *kq, struct knote *kn, int result);
static void knote_reset_priority(kqueue_t kqu, struct knote *kn, pthread_priority_t pp);
static ZONE_DEFINE(knote_zone, "knote zone",
sizeof(struct knote), ZC_CACHING | ZC_ZFREE_CLEARMEM);
static ZONE_DEFINE(kqfile_zone, "kqueue file zone",
sizeof(struct kqfile), ZC_ZFREE_CLEARMEM | ZC_NOTBITAG);
static ZONE_DEFINE(kqworkq_zone, "kqueue workq zone",
sizeof(struct kqworkq), ZC_ZFREE_CLEARMEM | ZC_NOTBITAG);
static ZONE_DEFINE(kqworkloop_zone, "kqueue workloop zone",
sizeof(struct kqworkloop), ZC_CACHING | ZC_ZFREE_CLEARMEM | ZC_NOTBITAG);
#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
static int filt_no_attach(struct knote *kn, struct kevent_qos_s *kev);
static void filt_no_detach(struct knote *kn);
static int filt_bad_event(struct knote *kn, long hint);
static int filt_bad_touch(struct knote *kn, struct kevent_qos_s *kev);
static int filt_bad_process(struct knote *kn, struct kevent_qos_s *kev);
SECURITY_READ_ONLY_EARLY(static struct filterops) bad_filtops = {
.f_attach = filt_no_attach,
.f_detach = filt_no_detach,
.f_event = filt_bad_event,
.f_touch = filt_bad_touch,
.f_process = filt_bad_process,
};
#if CONFIG_MEMORYSTATUS
extern const struct filterops memorystatus_filtops;
#endif /* CONFIG_MEMORYSTATUS */
extern const struct filterops fs_filtops;
extern const struct filterops sig_filtops;
extern const struct filterops machport_attach_filtops;
extern const struct filterops mach_port_filtops;
extern const struct filterops mach_port_set_filtops;
extern const struct filterops pipe_nfiltops;
extern const struct filterops pipe_rfiltops;
extern const struct filterops pipe_wfiltops;
extern const struct filterops ptsd_kqops;
extern const struct filterops ptmx_kqops;
extern const struct filterops soread_filtops;
extern const struct filterops sowrite_filtops;
extern const struct filterops sock_filtops;
extern const struct filterops soexcept_filtops;
extern const struct filterops spec_filtops;
extern const struct filterops bpfread_filtops;
extern const struct filterops necp_fd_rfiltops;
#if SKYWALK
extern const struct filterops skywalk_channel_rfiltops;
extern const struct filterops skywalk_channel_wfiltops;
extern const struct filterops skywalk_channel_efiltops;
#endif /* SKYWALK */
extern const struct filterops fsevent_filtops;
extern const struct filterops vnode_filtops;
extern const struct filterops tty_filtops;
const static struct filterops file_filtops;
const static struct filterops kqread_filtops;
const static struct filterops proc_filtops;
const static struct filterops timer_filtops;
const static struct filterops user_filtops;
const static struct filterops workloop_filtops;
#if CONFIG_EXCLAVES
extern const struct filterops exclaves_notification_filtops;
#endif /* CONFIG_EXCLAVES */
/*
*
* Rules for adding new filters to the system:
* Public filters:
* - Add a new "EVFILT_" option value to bsd/sys/event.h (typically a negative value)
* in the exported section of the header
* - Update the EVFILT_SYSCOUNT value to reflect the new addition
* - Add a filterops to the sysfilt_ops array. Public filters should be added at the end
* of the Public Filters section in the array.
* Private filters:
* - Add a new "EVFILT_" value to bsd/sys/event_private.h (typically a positive value)
* - Update the EVFILTID_MAX value to reflect the new addition
* - Add a filterops to the sysfilt_ops. Private filters should be added at the end of
* the Private filters section of the array.
*/
static_assert(EVFILTID_MAX < UINT8_MAX, "kn_filtid expects this to be true");
static const struct filterops * const sysfilt_ops[EVFILTID_MAX] = {
/* Public Filters */
[~EVFILT_READ] = &file_filtops,
[~EVFILT_WRITE] = &file_filtops,
[~EVFILT_AIO] = &bad_filtops,
[~EVFILT_VNODE] = &file_filtops,
[~EVFILT_PROC] = &proc_filtops,
[~EVFILT_SIGNAL] = &sig_filtops,
[~EVFILT_TIMER] = &timer_filtops,
[~EVFILT_MACHPORT] = &machport_attach_filtops,
[~EVFILT_FS] = &fs_filtops,
[~EVFILT_USER] = &user_filtops,
[~EVFILT_UNUSED_11] = &bad_filtops,
[~EVFILT_VM] = &bad_filtops,
[~EVFILT_SOCK] = &file_filtops,
#if CONFIG_MEMORYSTATUS
[~EVFILT_MEMORYSTATUS] = &memorystatus_filtops,
#else
[~EVFILT_MEMORYSTATUS] = &bad_filtops,
#endif
[~EVFILT_EXCEPT] = &file_filtops,
#if SKYWALK
[~EVFILT_NW_CHANNEL] = &file_filtops,
#else /* !SKYWALK */
[~EVFILT_NW_CHANNEL] = &bad_filtops,
#endif /* !SKYWALK */
[~EVFILT_WORKLOOP] = &workloop_filtops,
#if CONFIG_EXCLAVES
[~EVFILT_EXCLAVES_NOTIFICATION] = &exclaves_notification_filtops,
#else /* !CONFIG_EXCLAVES */
[~EVFILT_EXCLAVES_NOTIFICATION] = &bad_filtops,
#endif /* CONFIG_EXCLAVES*/
/* Private filters */
[EVFILTID_KQREAD] = &kqread_filtops,
[EVFILTID_PIPE_N] = &pipe_nfiltops,
[EVFILTID_PIPE_R] = &pipe_rfiltops,
[EVFILTID_PIPE_W] = &pipe_wfiltops,
[EVFILTID_PTSD] = &ptsd_kqops,
[EVFILTID_SOREAD] = &soread_filtops,
[EVFILTID_SOWRITE] = &sowrite_filtops,
[EVFILTID_SCK] = &sock_filtops,
[EVFILTID_SOEXCEPT] = &soexcept_filtops,
[EVFILTID_SPEC] = &spec_filtops,
[EVFILTID_BPFREAD] = &bpfread_filtops,
[EVFILTID_NECP_FD] = &necp_fd_rfiltops,
#if SKYWALK
[EVFILTID_SKYWALK_CHANNEL_W] = &skywalk_channel_wfiltops,
[EVFILTID_SKYWALK_CHANNEL_R] = &skywalk_channel_rfiltops,
[EVFILTID_SKYWALK_CHANNEL_E] = &skywalk_channel_efiltops,
#else /* !SKYWALK */
[EVFILTID_SKYWALK_CHANNEL_W] = &bad_filtops,
[EVFILTID_SKYWALK_CHANNEL_R] = &bad_filtops,
[EVFILTID_SKYWALK_CHANNEL_E] = &bad_filtops,
#endif /* !SKYWALK */
[EVFILTID_FSEVENT] = &fsevent_filtops,
[EVFILTID_VN] = &vnode_filtops,
[EVFILTID_TTY] = &tty_filtops,
[EVFILTID_PTMX] = &ptmx_kqops,
[EVFILTID_MACH_PORT] = &mach_port_filtops,
[EVFILTID_MACH_PORT_SET] = &mach_port_set_filtops,
/* fake filter for detached knotes, keep last */
[EVFILTID_DETACHED] = &bad_filtops,
};
static inline bool
kqr_thread_bound(workq_threadreq_t kqr)
{
return kqr->tr_state == WORKQ_TR_STATE_BOUND;
}
static inline bool
kqr_thread_requested_pending(workq_threadreq_t kqr)
{
workq_tr_state_t tr_state = kqr->tr_state;
return tr_state > WORKQ_TR_STATE_IDLE && tr_state < WORKQ_TR_STATE_BOUND;
}
static inline bool
kqr_thread_requested(workq_threadreq_t kqr)
{
return kqr->tr_state != WORKQ_TR_STATE_IDLE;
}
static inline thread_t
kqr_thread_fast(workq_threadreq_t kqr)
{
assert(kqr_thread_bound(kqr));
return kqr->tr_thread;
}
static inline thread_t
kqr_thread(workq_threadreq_t kqr)
{
return kqr_thread_bound(kqr) ? kqr->tr_thread : THREAD_NULL;
}
static inline struct kqworkloop *
kqr_kqworkloop(workq_threadreq_t kqr)
{
if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) {
return __container_of(kqr, struct kqworkloop, kqwl_request);
}
return NULL;
}
static inline kqueue_t
kqr_kqueue(proc_t p, workq_threadreq_t kqr)
{
kqueue_t kqu;
if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) {
kqu.kqwl = kqr_kqworkloop(kqr);
} else {
kqu.kqwq = p->p_fd.fd_wqkqueue;
assert(kqr >= kqu.kqwq->kqwq_request &&
kqr < kqu.kqwq->kqwq_request + KQWQ_NBUCKETS);
}
return kqu;
}
#if CONFIG_PREADOPT_TG
/* There are no guarantees about which locks are held when this is called */
inline thread_group_qos_t
kqr_preadopt_thread_group(workq_threadreq_t req)
{
struct kqworkloop *kqwl = kqr_kqworkloop(req);
return kqwl ? os_atomic_load(&kqwl->kqwl_preadopt_tg, relaxed) : NULL;
}
/* There are no guarantees about which locks are held when this is called */
inline _Atomic(thread_group_qos_t) *
kqr_preadopt_thread_group_addr(workq_threadreq_t req)
{
struct kqworkloop *kqwl = kqr_kqworkloop(req);
return kqwl ? (&kqwl->kqwl_preadopt_tg) : NULL;
}
#endif
/*
* kqueue/note lock implementations
*
* The kqueue lock guards the kq state, the state of its queues,
* and the kqueue-aware status and locks of individual knotes.
*
* The kqueue workq lock is used to protect state guarding the
* interaction of the kqueue with the workq. This state cannot
* be guarded by the kq lock - as it needs to be taken when we
* already have the waitq set lock held (during the waitq hook
* callback). It might be better to use the waitq lock itself
* for this, but the IRQ requirements make that difficult).
*
* Knote flags, filter flags, and associated data are protected
* by the underlying object lock - and are only ever looked at
* by calling the filter to get a [consistent] snapshot of that
* data.
*/
static inline void
kqlock(kqueue_t kqu)
{
lck_spin_lock(&kqu.kq->kq_lock);
}
static inline void
kqlock_held(__assert_only kqueue_t kqu)
{
LCK_SPIN_ASSERT(&kqu.kq->kq_lock, LCK_ASSERT_OWNED);
}
static inline void
kqunlock(kqueue_t kqu)
{
lck_spin_unlock(&kqu.kq->kq_lock);
}
static inline void
knhash_lock(struct filedesc *fdp)
{
lck_mtx_lock(&fdp->fd_knhashlock);
}
static inline void
knhash_unlock(struct filedesc *fdp)
{
lck_mtx_unlock(&fdp->fd_knhashlock);
}
/* wait event for knote locks */
static inline event_t
knote_lock_wev(struct knote *kn)
{
return (event_t)(&kn->kn_hook);
}
/* wait event for kevent_register_wait_* */
static inline event64_t
knote_filt_wev64(struct knote *kn)
{
/* kdp_workloop_sync_wait_find_owner knows about this */
return CAST_EVENT64_T(kn);
}
/* wait event for knote_post/knote_drop */
static inline event_t
knote_post_wev(struct knote *kn)
{
return &kn->kn_kevent;
}
/*!
* @function knote_has_qos
*
* @brief
* Whether the knote has a regular QoS.
*
* @discussion
* kn_qos_override is:
* - 0 on kqfiles
* - THREAD_QOS_LAST for special buckets (manager)
*
* Other values mean the knote participates to QoS propagation.
*/
static inline bool
knote_has_qos(struct knote *kn)
{
return kn->kn_qos_override > 0 && kn->kn_qos_override < THREAD_QOS_LAST;
}
#pragma mark knote locks
/*
* Enum used by the knote_lock_* functions.
*
* KNOTE_KQ_LOCK_ALWAYS
* The function will always return with the kq lock held.
*
* KNOTE_KQ_LOCK_ON_SUCCESS
* The function will return with the kq lock held if it was successful
* (knote_lock() is the only function that can fail).
*
* KNOTE_KQ_LOCK_ON_FAILURE
* The function will return with the kq lock held if it was unsuccessful
* (knote_lock() is the only function that can fail).
*
* KNOTE_KQ_UNLOCK:
* The function returns with the kq unlocked.
*/
enum kqlocking {
KNOTE_KQ_LOCK_ALWAYS,
KNOTE_KQ_LOCK_ON_SUCCESS,
KNOTE_KQ_LOCK_ON_FAILURE,
KNOTE_KQ_UNLOCK,
};
static struct knote_lock_ctx *
knote_lock_ctx_find(kqueue_t kqu, struct knote *kn)
{
struct knote_lock_ctx *ctx;
LIST_FOREACH(ctx, &kqu.kq->kq_knlocks, knlc_link) {
if (ctx->knlc_knote == kn) {
return ctx;
}
}
panic("knote lock context not found: %p", kn);
__builtin_trap();
}
/* slowpath of knote_lock() */
__attribute__((noinline))
static bool __result_use_check
knote_lock_slow(kqueue_t kqu, struct knote *kn,
struct knote_lock_ctx *knlc, int kqlocking)
{
struct knote_lock_ctx *owner_lc;
struct uthread *uth = current_uthread();
wait_result_t wr;
kqlock_held(kqu);
owner_lc = knote_lock_ctx_find(kqu, kn);
#if DEBUG || DEVELOPMENT
knlc->knlc_state = KNOTE_LOCK_CTX_WAITING;
#endif
owner_lc->knlc_waiters++;
/*
* Make our lock context visible to knote_unlock()
*/
uth->uu_knlock = knlc;
wr = lck_spin_sleep_with_inheritor(&kqu.kq->kq_lock, LCK_SLEEP_UNLOCK,
knote_lock_wev(kn), owner_lc->knlc_thread,
THREAD_UNINT | THREAD_WAIT_NOREPORT, TIMEOUT_WAIT_FOREVER);
if (wr == THREAD_RESTART) {
/*
* We haven't been woken up by knote_unlock() but knote_unlock_cancel.
* We need to cleanup the state since no one did.
*/
uth->uu_knlock = NULL;
#if DEBUG || DEVELOPMENT
assert(knlc->knlc_state == KNOTE_LOCK_CTX_WAITING);
knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED;
#endif
if (kqlocking == KNOTE_KQ_LOCK_ALWAYS ||
kqlocking == KNOTE_KQ_LOCK_ON_FAILURE) {
kqlock(kqu);
}
return false;
} else {
if (kqlocking == KNOTE_KQ_LOCK_ALWAYS ||
kqlocking == KNOTE_KQ_LOCK_ON_SUCCESS) {
kqlock(kqu);
#if DEBUG || DEVELOPMENT
/*
* This state is set under the lock so we can't
* really assert this unless we hold the lock.
*/
assert(knlc->knlc_state == KNOTE_LOCK_CTX_LOCKED);
#endif
}
return true;
}
}
/*
* Attempts to take the "knote" lock.
*
* Called with the kqueue lock held.
*
* Returns true if the knote lock is acquired, false if it has been dropped
*/
static bool __result_use_check
knote_lock(kqueue_t kqu, struct knote *kn, struct knote_lock_ctx *knlc,
enum kqlocking kqlocking)
{
kqlock_held(kqu);
#if DEBUG || DEVELOPMENT
assert(knlc->knlc_state == KNOTE_LOCK_CTX_UNLOCKED);
#endif
knlc->knlc_knote = kn;
knlc->knlc_thread = current_thread();
knlc->knlc_waiters = 0;
if (__improbable(kn->kn_status & KN_LOCKED)) {
return knote_lock_slow(kqu, kn, knlc, kqlocking);
}
/*
* When the knote will be dropped, the knote lock is taken before
* KN_DROPPING is set, and then the knote will be removed from any
* hash table that references it before the lock is canceled.
*/
assert((kn->kn_status & KN_DROPPING) == 0);
LIST_INSERT_HEAD(&kqu.kq->kq_knlocks, knlc, knlc_link);
kn->kn_status |= KN_LOCKED;
#if DEBUG || DEVELOPMENT
knlc->knlc_state = KNOTE_LOCK_CTX_LOCKED;
#endif
if (kqlocking == KNOTE_KQ_UNLOCK ||
kqlocking == KNOTE_KQ_LOCK_ON_FAILURE) {
kqunlock(kqu);
}
return true;
}
/*
* Unlocks a knote successfully locked with knote_lock().
*
* Called with the kqueue lock held.
*
* Returns with the kqueue lock held according to KNOTE_KQ_* mode.
*/
static void
knote_unlock(kqueue_t kqu, struct knote *kn,
struct knote_lock_ctx *knlc, enum kqlocking kqlocking)
{
kqlock_held(kqu);
assert(knlc->knlc_knote == kn);
assert(kn->kn_status & KN_LOCKED);
#if DEBUG || DEVELOPMENT
assert(knlc->knlc_state == KNOTE_LOCK_CTX_LOCKED);
#endif
LIST_REMOVE(knlc, knlc_link);
if (knlc->knlc_waiters) {
thread_t thread = THREAD_NULL;
wakeup_one_with_inheritor(knote_lock_wev(kn), THREAD_AWAKENED,
LCK_WAKE_DEFAULT, &thread);
/*
* knote_lock_slow() publishes the lock context of waiters
* in uthread::uu_knlock.
*
* Reach out and make this context the new owner.
*/
struct uthread *ut = get_bsdthread_info(thread);
struct knote_lock_ctx *next_owner_lc = ut->uu_knlock;
assert(next_owner_lc->knlc_knote == kn);
next_owner_lc->knlc_waiters = knlc->knlc_waiters - 1;
LIST_INSERT_HEAD(&kqu.kq->kq_knlocks, next_owner_lc, knlc_link);
#if DEBUG || DEVELOPMENT
next_owner_lc->knlc_state = KNOTE_LOCK_CTX_LOCKED;
#endif
ut->uu_knlock = NULL;
thread_deallocate_safe(thread);
} else {
kn->kn_status &= ~KN_LOCKED;
}
if ((kn->kn_status & KN_MERGE_QOS) && !(kn->kn_status & KN_POSTING)) {
/*
* No f_event() in flight anymore, we can leave QoS "Merge" mode
*
* See knote_adjust_qos()
*/
kn->kn_status &= ~KN_MERGE_QOS;
}
if (kqlocking == KNOTE_KQ_UNLOCK) {
kqunlock(kqu);
}
#if DEBUG || DEVELOPMENT
knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED;
#endif
}
/*
* Aborts all waiters for a knote lock, and unlock the knote.
*
* Called with the kqueue lock held.
*
* Returns with the kqueue unlocked.
*/
static void
knote_unlock_cancel(struct kqueue *kq, struct knote *kn,
struct knote_lock_ctx *knlc)
{
kqlock_held(kq);
assert(knlc->knlc_knote == kn);
assert(kn->kn_status & KN_LOCKED);
assert(kn->kn_status & KN_DROPPING);
LIST_REMOVE(knlc, knlc_link);
kn->kn_status &= ~KN_LOCKED;
kqunlock(kq);
if (knlc->knlc_waiters) {
wakeup_all_with_inheritor(knote_lock_wev(kn), THREAD_RESTART);
}
#if DEBUG || DEVELOPMENT
knlc->knlc_state = KNOTE_LOCK_CTX_UNLOCKED;
#endif
}
/*
* Call the f_event hook of a given filter.
*
* Takes a use count to protect against concurrent drops.
* Called with the object lock held.
*/
static void
knote_post(struct knote *kn, long hint)
{
struct kqueue *kq = knote_get_kq(kn);
int dropping, result;
kqlock(kq);
if (__improbable(kn->kn_status & (KN_DROPPING | KN_VANISHED))) {
return kqunlock(kq);
}
if (__improbable(kn->kn_status & KN_POSTING)) {
panic("KNOTE() called concurrently on knote %p", kn);
}
kn->kn_status |= KN_POSTING;
kqunlock(kq);
result = filter_call(knote_fops(kn), f_event(kn, hint));
kqlock(kq);
/* Someone dropped the knote/the monitored object vanished while we
* were in f_event, swallow the side effects of the post.
*/
dropping = (kn->kn_status & (KN_DROPPING | KN_VANISHED));
if (!dropping && (result & FILTER_ADJUST_EVENT_IOTIER_BIT)) {
kqueue_update_iotier_override(kq);
}
if (!dropping && (result & FILTER_ACTIVE)) {
knote_activate(kq, kn, result);
}
if ((kn->kn_status & KN_LOCKED) == 0) {
/*
* There's no other f_* call in flight, we can leave QoS "Merge" mode.
*
* See knote_adjust_qos()
*/
kn->kn_status &= ~(KN_POSTING | KN_MERGE_QOS);
} else {
kn->kn_status &= ~KN_POSTING;
}
if (__improbable(dropping)) {
thread_wakeup(knote_post_wev(kn));
}
kqunlock(kq);
}
/*
* Called by knote_drop() and knote_fdclose() to wait for the last f_event()
* caller to be done.
*
* - kq locked at entry
* - kq unlocked at exit
*/
static void
knote_wait_for_post(struct kqueue *kq, struct knote *kn)
{
kqlock_held(kq);
assert(kn->kn_status & (KN_DROPPING | KN_VANISHED));
if (kn->kn_status & KN_POSTING) {
lck_spin_sleep(&kq->kq_lock, LCK_SLEEP_UNLOCK, knote_post_wev(kn),
THREAD_UNINT | THREAD_WAIT_NOREPORT);
} else {
kqunlock(kq);
}
}
#pragma mark knote helpers for filters
OS_ALWAYS_INLINE
void *
knote_kn_hook_get_raw(struct knote *kn)
{
uintptr_t *addr = &kn->kn_hook;
void *hook = (void *) *addr;
#if __has_feature(ptrauth_calls)
if (hook) {
uint16_t blend = kn->kn_filter;
blend |= (kn->kn_filtid << 8);
blend ^= OS_PTRAUTH_DISCRIMINATOR("kn.kn_hook");
hook = ptrauth_auth_data(hook, ptrauth_key_process_independent_data,
ptrauth_blend_discriminator(addr, blend));
}
#endif
return hook;
}
OS_ALWAYS_INLINE void
knote_kn_hook_set_raw(struct knote *kn, void *kn_hook)
{
uintptr_t *addr = &kn->kn_hook;
#if __has_feature(ptrauth_calls)
if (kn_hook) {
uint16_t blend = kn->kn_filter;
blend |= (kn->kn_filtid << 8);
blend ^= OS_PTRAUTH_DISCRIMINATOR("kn.kn_hook");
kn_hook = ptrauth_sign_unauthenticated(kn_hook,
ptrauth_key_process_independent_data,
ptrauth_blend_discriminator(addr, blend));
}
#endif
*addr = (uintptr_t) kn_hook;
}
OS_ALWAYS_INLINE
void
knote_set_error(struct knote *kn, int error)
{
kn->kn_flags |= EV_ERROR;
kn->kn_sdata = error;
}
OS_ALWAYS_INLINE
int64_t
knote_low_watermark(const struct knote *kn)
{
return (kn->kn_sfflags & NOTE_LOWAT) ? kn->kn_sdata : 1;
}
/*!
* @function knote_fill_kevent_with_sdata
*
* @brief
* Fills in a kevent from the current content of a knote.
*
* @discussion
* This is meant to be called from filter's f_process hooks.
* The kevent data is filled with kn->kn_sdata.
*
* kn->kn_fflags is cleared if kn->kn_flags has EV_CLEAR set.
*
* Using knote_fill_kevent is typically preferred.
*/
OS_ALWAYS_INLINE
void
knote_fill_kevent_with_sdata(struct knote *kn, struct kevent_qos_s *kev)
{
#define knote_assert_aliases(name1, offs1, name2) \
static_assert(offsetof(struct kevent_qos_s, name1) + offs1 == \
offsetof(struct kevent_internal_s, name2), \
"kevent_qos_s::" #name1 " and kevent_internal_s::" #name2 "need to alias")
/*
* All the code makes assumptions on these aliasing,
* so make sure we fail the build if we ever ever ever break them.
*/
knote_assert_aliases(ident, 0, kei_ident);
#ifdef __LITTLE_ENDIAN__
knote_assert_aliases(filter, 0, kei_filter); // non trivial overlap
knote_assert_aliases(filter, 1, kei_filtid); // non trivial overlap
#else
knote_assert_aliases(filter, 0, kei_filtid); // non trivial overlap
knote_assert_aliases(filter, 1, kei_filter); // non trivial overlap
#endif
knote_assert_aliases(flags, 0, kei_flags);
knote_assert_aliases(qos, 0, kei_qos);
knote_assert_aliases(udata, 0, kei_udata);
knote_assert_aliases(fflags, 0, kei_fflags);
knote_assert_aliases(xflags, 0, kei_sfflags); // non trivial overlap
knote_assert_aliases(data, 0, kei_sdata); // non trivial overlap
knote_assert_aliases(ext, 0, kei_ext);
#undef knote_assert_aliases
/*
* Fix the differences between kevent_qos_s and kevent_internal_s:
* - xflags is where kn_sfflags lives, we need to zero it
* - fixup the high bits of `filter` where kn_filtid lives
*/
*kev = *(struct kevent_qos_s *)&kn->kn_kevent;
kev->xflags = 0;
kev->filter |= 0xff00;
if (kn->kn_flags & EV_CLEAR) {
kn->kn_fflags = 0;
}
}
/*!
* @function knote_fill_kevent
*
* @brief
* Fills in a kevent from the current content of a knote.
*
* @discussion
* This is meant to be called from filter's f_process hooks.
* The kevent data is filled with the passed in data.
*
* kn->kn_fflags is cleared if kn->kn_flags has EV_CLEAR set.
*/
OS_ALWAYS_INLINE
void
knote_fill_kevent(struct knote *kn, struct kevent_qos_s *kev, int64_t data)
{
knote_fill_kevent_with_sdata(kn, kev);
kev->filter = kn->kn_filter;
kev->data = data;
}
#pragma mark file_filtops
static int
filt_fileattach(struct knote *kn, struct kevent_qos_s *kev)
{
return fo_kqfilter(kn->kn_fp, kn, kev);
}
SECURITY_READ_ONLY_EARLY(static struct filterops) file_filtops = {
.f_isfd = 1,
.f_attach = filt_fileattach,
};
#pragma mark kqread_filtops
#define f_flag fp_glob->fg_flag
#define f_ops fp_glob->fg_ops
#define f_lflags fp_glob->fg_lflags
static void
filt_kqdetach(struct knote *kn)
{
struct kqfile *kqf = (struct kqfile *)fp_get_data(kn->kn_fp);
struct kqueue *kq = &kqf->kqf_kqueue;
kqlock(kq);
KNOTE_DETACH(&kqf->kqf_sel.si_note, kn);
kqunlock(kq);
}
static int
filt_kqueue(struct knote *kn, __unused long hint)
{
struct kqueue *kq = (struct kqueue *)fp_get_data(kn->kn_fp);
return kq->kq_count > 0;
}
static int
filt_kqtouch(struct knote *kn, struct kevent_qos_s *kev)
{
#pragma unused(kev)
struct kqueue *kq = (struct kqueue *)fp_get_data(kn->kn_fp);
int res;
kqlock(kq);
res = (kq->kq_count > 0);
kqunlock(kq);
return res;
}
static int
filt_kqprocess(struct knote *kn, struct kevent_qos_s *kev)
{
struct kqueue *kq = (struct kqueue *)fp_get_data(kn->kn_fp);
int res = 0;
kqlock(kq);
if (kq->kq_count) {
knote_fill_kevent(kn, kev, kq->kq_count);
res = 1;
}
kqunlock(kq);
return res;
}
SECURITY_READ_ONLY_EARLY(static struct filterops) kqread_filtops = {
.f_isfd = 1,
.f_detach = filt_kqdetach,
.f_event = filt_kqueue,
.f_touch = filt_kqtouch,
.f_process = filt_kqprocess,
};
#pragma mark proc_filtops
static int
filt_procattach(struct knote *kn, __unused struct kevent_qos_s *kev)
{
struct proc *p;
assert(PID_MAX < NOTE_PDATAMASK);
if ((kn->kn_sfflags & (NOTE_TRACK | NOTE_TRACKERR | NOTE_CHILD)) != 0) {
knote_set_error(kn, ENOTSUP);
return 0;
}
p = proc_find((int)kn->kn_id);
if (p == NULL) {
knote_set_error(kn, ESRCH);
return 0;
}
const uint32_t 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 */
}
if (cansignal(current_proc(), kauth_cred_get(), p, SIGKILL)) {
break; /* allowed to signal => ok */
}
proc_rele(p);
knote_set_error(kn, EACCES);
return 0;
} while (0);
}
kn->kn_proc = p;
kn->kn_flags |= EV_CLEAR; /* automatically set */
kn->kn_sdata = 0; /* incoming data is ignored */
proc_klist_lock();
KNOTE_ATTACH(&p->p_klist, kn);
proc_klist_unlock();
proc_rele(p);
/*
* only captures edge-triggered events after this point
* so it can't already be fired.
*/
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_proc;
if (p != PROC_NULL) {
kn->kn_proc = PROC_NULL;
KNOTE_DETACH(&p->p_klist, kn);
}
proc_klist_unlock();
}
static int
filt_procevent(struct knote *kn, long hint)
{
u_int event;
/* ALWAYS CALLED WITH proc_klist_lock */
/*
* Note: a lot of bits in hint may be obtained from the knote
* To free some of those bits, see <rdar://problem/12592988> Freeing up
* bits in hint for filt_procevent
*
* mask off extra data
*/
event = (u_int)hint & NOTE_PCTRLMASK;
/*
* termination lifecycle events can happen while a debugger
* has reparented a process, in which case notifications
* should be quashed except to the tracing parent. When
* the debugger reaps the child (either via wait4(2) or
* process exit), the child will be reparented to the original
* parent and these knotes re-fired.
*/
if (event & NOTE_EXIT) {
if ((kn->kn_proc->p_oppid != 0)
&& (proc_getpid(knote_get_kq(kn)->kq_p) != kn->kn_proc->p_ppid)) {
/*
* This knote is not for the current ptrace(2) parent, ignore.
*/
return 0;
}
}
/*
* if the user is interested in this event, record it.
*/
if (kn->kn_sfflags & event) {
kn->kn_fflags |= event;
}
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
if ((event == NOTE_REAP) || ((event == NOTE_EXIT) && !(kn->kn_sfflags & NOTE_REAP))) {
kn->kn_flags |= (EV_EOF | EV_ONESHOT);
}
#pragma clang diagnostic pop
/*
* The kernel has a wrapper in place that returns the same data
* as is collected here, in kn_hook32. Any changes to how
* NOTE_EXITSTATUS and NOTE_EXIT_DETAIL are collected
* should also be reflected in the proc_pidnoteexit() wrapper.
*/
if (event == NOTE_EXIT) {
kn->kn_hook32 = 0;
if ((kn->kn_sfflags & NOTE_EXITSTATUS) != 0) {
kn->kn_fflags |= NOTE_EXITSTATUS;
kn->kn_hook32 |= (hint & NOTE_PDATAMASK);
}
if ((kn->kn_sfflags & NOTE_EXIT_DETAIL) != 0) {
kn->kn_fflags |= NOTE_EXIT_DETAIL;
if ((kn->kn_proc->p_lflag &
P_LTERM_DECRYPTFAIL) != 0) {
kn->kn_hook32 |= NOTE_EXIT_DECRYPTFAIL;
}
if ((kn->kn_proc->p_lflag &
P_LTERM_JETSAM) != 0) {
kn->kn_hook32 |= NOTE_EXIT_MEMORY;
switch (kn->kn_proc->p_lflag & P_JETSAM_MASK) {
case P_JETSAM_VMPAGESHORTAGE:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_VMPAGESHORTAGE;
break;
case P_JETSAM_VMTHRASHING:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_VMTHRASHING;
break;
case P_JETSAM_FCTHRASHING:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_FCTHRASHING;
break;
case P_JETSAM_VNODE:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_VNODE;
break;
case P_JETSAM_HIWAT:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_HIWAT;
break;
case P_JETSAM_PID:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_PID;
break;
case P_JETSAM_IDLEEXIT:
kn->kn_hook32 |= NOTE_EXIT_MEMORY_IDLE;
break;
}
}
if ((proc_getcsflags(kn->kn_proc) &
CS_KILLED) != 0) {
kn->kn_hook32 |= NOTE_EXIT_CSERROR;
}
}
}
/* if we have any matching state, activate the knote */
return kn->kn_fflags != 0;
}
static int
filt_proctouch(struct knote *kn, struct kevent_qos_s *kev)
{
int res;
proc_klist_lock();
/* accept new filter flags and mask off output events no long interesting */
kn->kn_sfflags = kev->fflags;
/* restrict the current results to the (smaller?) set of new interest */
/*
* For compatibility with previous implementations, we leave kn_fflags
* as they were before.
*/
//kn->kn_fflags &= kn->kn_sfflags;
res = (kn->kn_fflags != 0);
proc_klist_unlock();
return res;
}
static int
filt_procprocess(struct knote *kn, struct kevent_qos_s *kev)
{
int res = 0;
proc_klist_lock();
if (kn->kn_fflags) {
knote_fill_kevent(kn, kev, kn->kn_hook32);
kn->kn_hook32 = 0;
res = 1;
}
proc_klist_unlock();
return res;
}
SECURITY_READ_ONLY_EARLY(static struct filterops) proc_filtops = {
.f_attach = filt_procattach,
.f_detach = filt_procdetach,
.f_event = filt_procevent,
.f_touch = filt_proctouch,
.f_process = filt_procprocess,
};
#pragma mark timer_filtops
struct filt_timer_params {
uint64_t deadline; /* deadline in abs/cont time
* (or 0 if NOTE_ABSOLUTE and deadline is in past) */
uint64_t leeway; /* leeway in abstime, or 0 if none */
uint64_t interval; /* interval in abstime or 0 if non-repeating timer */
};
/*
* Values stored in the knote at rest (using Mach absolute time units)
*
* kn->kn_thcall where the thread_call object is stored
* kn->kn_ext[0] next deadline or 0 if immediate expiration
* kn->kn_ext[1] leeway value
* kn->kn_sdata interval timer: the interval
* absolute/deadline timer: 0
* kn->kn_hook32 timer state (with gencount)
*
* TIMER_IDLE:
* The timer has either never been scheduled or been cancelled.
* It is safe to schedule a new one in this state.
*
* TIMER_ARMED:
* The timer has been scheduled
*
* TIMER_FIRED
* The timer has fired and an event needs to be delivered.
* When in this state, the callout may still be running.
*
* TIMER_IMMEDIATE
* The timer has fired at registration time, and the callout was never
* dispatched.
*/
#define TIMER_IDLE 0x0
#define TIMER_ARMED 0x1
#define TIMER_FIRED 0x2
#define TIMER_IMMEDIATE 0x3
#define TIMER_STATE_MASK 0x3
#define TIMER_GEN_INC 0x4
static void
filt_timer_set_params(struct knote *kn, struct filt_timer_params *params)
{
kn->kn_ext[0] = params->deadline;
kn->kn_ext[1] = params->leeway;
kn->kn_sdata = params->interval;
}
/*
* filt_timervalidate - process data from user
*
* Sets up the deadline, interval, and leeway from the provided user data
*
* Input:
* kn_sdata timer deadline or interval time
* kn_sfflags style of timer, unit of measurement
*
* Output:
* struct filter_timer_params to apply to the filter with
* filt_timer_set_params when changes are ready to be commited.
*
* Returns:
* EINVAL Invalid user data parameters
* ERANGE Various overflows with the parameters
*
* Called with timer filter lock held.
*/
static int
filt_timervalidate(const struct kevent_qos_s *kev,
struct filt_timer_params *params)
{
/*
* There are 5 knobs that need to be chosen for a timer registration:
*
* A) Units of time (what is the time duration of the specified number)
* Absolute and interval take:
* NOTE_SECONDS, NOTE_USECONDS, NOTE_NSECONDS, NOTE_MACHTIME
* Defaults to milliseconds if not specified
*
* B) Clock epoch (what is the zero point of the specified number)
* For interval, there is none
* For absolute, defaults to the gettimeofday/calendar epoch
* With NOTE_MACHTIME, uses mach_absolute_time()
* With NOTE_MACHTIME and NOTE_MACH_CONTINUOUS_TIME, uses mach_continuous_time()
*
* C) The knote's behavior on delivery
* Interval timer causes the knote to arm for the next interval unless one-shot is set
* Absolute is a forced one-shot timer which deletes on delivery
* TODO: Add a way for absolute to be not forced one-shot
*
* D) Whether the time duration is relative to now or absolute
* Interval fires at now + duration when it is set up
* Absolute fires at now + difference between now walltime and passed in walltime
* With NOTE_MACHTIME it fires at an absolute MAT or MCT.
*
* E) Whether the timer continues to tick across sleep
* By default all three do not.
* For interval and absolute, NOTE_MACH_CONTINUOUS_TIME causes them to tick across sleep
* With NOTE_ABSOLUTE | NOTE_MACHTIME | NOTE_MACH_CONTINUOUS_TIME:
* expires when mach_continuous_time() is > the passed in value.
*/
uint64_t multiplier;
boolean_t use_abstime = FALSE;
switch (kev->fflags & (NOTE_SECONDS | NOTE_USECONDS | NOTE_NSECONDS | NOTE_MACHTIME)) {
case NOTE_SECONDS:
multiplier = NSEC_PER_SEC;
break;
case NOTE_USECONDS:
multiplier = NSEC_PER_USEC;
break;
case NOTE_NSECONDS:
multiplier = 1;
break;
case NOTE_MACHTIME:
multiplier = 0;
use_abstime = TRUE;
break;
case 0: /* milliseconds (default) */
multiplier = NSEC_PER_SEC / 1000;
break;
default:
return EINVAL;
}
/* transform the leeway in kn_ext[1] to same time scale */
if (kev->fflags & NOTE_LEEWAY) {
uint64_t leeway_abs;
if (use_abstime) {
leeway_abs = (uint64_t)kev->ext[1];
} else {
uint64_t leeway_ns;
if (os_mul_overflow((uint64_t)kev->ext[1], multiplier, &leeway_ns)) {
return ERANGE;
}
nanoseconds_to_absolutetime(leeway_ns, &leeway_abs);
}
params->leeway = leeway_abs;
} else {
params->leeway = 0;
}
if (kev->fflags & NOTE_ABSOLUTE) {
uint64_t deadline_abs;
if (use_abstime) {
deadline_abs = (uint64_t)kev->data;
} else {
uint64_t calendar_deadline_ns;
if (os_mul_overflow((uint64_t)kev->data, multiplier, &calendar_deadline_ns)) {
return ERANGE;
}
/* calendar_deadline_ns is in nanoseconds since the epoch */
clock_sec_t seconds;
clock_nsec_t nanoseconds;
/*
* Note that the conversion through wall-time is only done once.
*
* If the relationship between MAT and gettimeofday changes,
* the underlying timer does not update.
*
* TODO: build a wall-time denominated timer_call queue
* and a flag to request DTRTing with wall-time timers
*/
clock_get_calendar_nanotime(&seconds, &nanoseconds);
uint64_t calendar_now_ns = (uint64_t)seconds * NSEC_PER_SEC + nanoseconds;
/* if deadline is in the future */
if (calendar_now_ns < calendar_deadline_ns) {
uint64_t interval_ns = calendar_deadline_ns - calendar_now_ns;
uint64_t interval_abs;
nanoseconds_to_absolutetime(interval_ns, &interval_abs);
/*
* Note that the NOTE_MACH_CONTINUOUS_TIME flag here only
* causes the timer to keep ticking across sleep, but
* it does not change the calendar timebase.
*/
if (kev->fflags & NOTE_MACH_CONTINUOUS_TIME) {
clock_continuoustime_interval_to_deadline(interval_abs,
&deadline_abs);
} else {
clock_absolutetime_interval_to_deadline(interval_abs,
&deadline_abs);
}
} else {
deadline_abs = 0; /* cause immediate expiration */
}
}
params->deadline = deadline_abs;
params->interval = 0; /* NOTE_ABSOLUTE is non-repeating */
} else if (kev->data < 0) {
/*
* Negative interval timers fire immediately, once.
*
* Ideally a negative interval would be an error, but certain clients
* pass negative values on accident, and expect an event back.
*
* In the old implementation the timer would repeat with no delay
* N times until mach_absolute_time() + (N * interval) underflowed,
* then it would wait ~forever by accidentally arming a timer for the far future.
*
* We now skip the power-wasting hot spin phase and go straight to the idle phase.
*/
params->deadline = 0; /* expire immediately */
params->interval = 0; /* non-repeating */
} else {
uint64_t interval_abs = 0;
if (use_abstime) {
interval_abs = (uint64_t)kev->data;
} else {
uint64_t interval_ns;
if (os_mul_overflow((uint64_t)kev->data, multiplier, &interval_ns)) {
return ERANGE;
}
nanoseconds_to_absolutetime(interval_ns, &interval_abs);
}
uint64_t deadline = 0;
if (kev->fflags & NOTE_MACH_CONTINUOUS_TIME) {
clock_continuoustime_interval_to_deadline(interval_abs, &deadline);
} else {
clock_absolutetime_interval_to_deadline(interval_abs, &deadline);
}
params->deadline = deadline;
params->interval = interval_abs;
}
return 0;
}
/*
* filt_timerexpire - the timer callout routine
*/
static void
filt_timerexpire(void *knx, void *state_on_arm)
{
struct knote *kn = knx;
uint32_t state = (uint32_t)(uintptr_t)state_on_arm;
uint32_t fired_state = state ^ TIMER_ARMED ^ TIMER_FIRED;
if (os_atomic_cmpxchg(&kn->kn_hook32, state, fired_state, relaxed)) {
// our f_event always would say FILTER_ACTIVE,
// so be leaner and just do it.
struct kqueue *kq = knote_get_kq(kn);
kqlock(kq);
knote_activate(kq, kn, FILTER_ACTIVE);
kqunlock(kq);
} else {
/*
* The timer has been reprogrammed or canceled since it was armed,
* and this is a late firing for the timer, just ignore it.
*/
}
}
/*
* Does this deadline needs a timer armed for it, or has it expired?
*/
static bool
filt_timer_is_ready(struct knote *kn)
{
uint64_t now, deadline = kn->kn_ext[0];
if (deadline == 0) {
return true;
}
if (kn->kn_sfflags & NOTE_MACH_CONTINUOUS_TIME) {
now = mach_continuous_time();
} else {
now = mach_absolute_time();
}
return deadline <= now;
}
/*
* Arm a timer
*
* It is the responsibility of the caller to make sure the timer call
* has completed or been cancelled properly prior to arming it.
*/
static void
filt_timerarm(struct knote *kn)
{
uint64_t deadline = kn->kn_ext[0];
uint64_t leeway = kn->kn_ext[1];
uint32_t state;
int filter_flags = kn->kn_sfflags;
unsigned int timer_flags = 0;
if (filter_flags & NOTE_CRITICAL) {
timer_flags |= THREAD_CALL_DELAY_USER_CRITICAL;
} else if (filter_flags & NOTE_BACKGROUND) {
timer_flags |= THREAD_CALL_DELAY_USER_BACKGROUND;
} else {
timer_flags |= THREAD_CALL_DELAY_USER_NORMAL;
}
if (filter_flags & NOTE_LEEWAY) {
timer_flags |= THREAD_CALL_DELAY_LEEWAY;
}
if (filter_flags & NOTE_MACH_CONTINUOUS_TIME) {
timer_flags |= THREAD_CALL_CONTINUOUS;
}
/*
* Move to ARMED.
*
* We increase the gencount, and setup the thread call with this expected
* state. It means that if there was a previous generation of the timer in
* flight that needs to be ignored, then 3 things are possible:
*
* - the timer fires first, filt_timerexpire() and sets the state to FIRED
* but we clobber it with ARMED and a new gencount. The knote will still
* be activated, but filt_timerprocess() which is serialized with this
* call will not see the FIRED bit set and will not deliver an event.
*
* - this code runs first, but filt_timerexpire() comes second. Because it
* knows an old gencount, it will debounce and not activate the knote.
*
* - filt_timerexpire() wasn't in flight yet, and thread_call_enter below
* will just cancel it properly.
*
* This is important as userspace expects to never be woken up for past
* timers after filt_timertouch ran.
*/
state = os_atomic_load(&kn->kn_hook32, relaxed);
state &= ~TIMER_STATE_MASK;
state += TIMER_GEN_INC + TIMER_ARMED;
os_atomic_store(&kn->kn_hook32, state, relaxed);
thread_call_enter_delayed_with_leeway(kn->kn_thcall,
(void *)(uintptr_t)state, deadline, leeway, timer_flags);
}
/*
* Mark a timer as "already fired" when it is being reprogrammed
*
* If there is a timer in flight, this will do a best effort at canceling it,
* but will not wait. If the thread call was in flight, having set the
* TIMER_IMMEDIATE bit will debounce a filt_timerexpire() racing with this
* cancelation.
*/
static void
filt_timerfire_immediate(struct knote *kn)
{
uint32_t state;
static_assert(TIMER_IMMEDIATE == TIMER_STATE_MASK,
"validate that this atomic or will transition to IMMEDIATE");
state = os_atomic_or_orig(&kn->kn_hook32, TIMER_IMMEDIATE, relaxed);
if ((state & TIMER_STATE_MASK) == TIMER_ARMED) {
thread_call_cancel(kn->kn_thcall);
}
}
/*
* Allocate a thread call for the knote's lifetime, and kick off the timer.
*/
static int
filt_timerattach(struct knote *kn, struct kevent_qos_s *kev)
{
thread_call_t callout;
struct filt_timer_params params;
int error;
if ((error = filt_timervalidate(kev, &params)) != 0) {
knote_set_error(kn, error);
return 0;
}
callout = thread_call_allocate_with_options(filt_timerexpire,
(thread_call_param_t)kn, THREAD_CALL_PRIORITY_HIGH,
THREAD_CALL_OPTIONS_ONCE);
if (NULL == callout) {
knote_set_error(kn, ENOMEM);
return 0;
}
filt_timer_set_params(kn, &params);
kn->kn_thcall = callout;
kn->kn_flags |= EV_CLEAR;
os_atomic_store(&kn->kn_hook32, TIMER_IDLE, relaxed);
/* NOTE_ABSOLUTE implies EV_ONESHOT */
if (kn->kn_sfflags & NOTE_ABSOLUTE) {
kn->kn_flags |= EV_ONESHOT;
}
if (filt_timer_is_ready(kn)) {
os_atomic_store(&kn->kn_hook32, TIMER_IMMEDIATE, relaxed);
return FILTER_ACTIVE;
} else {
filt_timerarm(kn);
return 0;
}
}
/*
* Shut down the timer if it's running, and free the callout.
*/
static void
filt_timerdetach(struct knote *kn)
{
__assert_only boolean_t freed;
/*
* Unconditionally cancel to make sure there can't be any filt_timerexpire()
* running anymore.
*/
thread_call_cancel_wait(kn->kn_thcall);
freed = thread_call_free(kn->kn_thcall);
assert(freed);
}
/*
* filt_timertouch - update timer 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 int
filt_timertouch(struct knote *kn, struct kevent_qos_s *kev)
{
struct filt_timer_params params;
uint32_t changed_flags = (kn->kn_sfflags ^ kev->fflags);
int error;
if (kev->qos && (knote_get_kq(kn)->kq_state & KQ_WORKLOOP) &&
!_pthread_priority_thread_qos(kev->qos)) {
/* validate usage of FILTER_UPDATE_REQ_QOS */
kev->flags |= EV_ERROR;
kev->data = ERANGE;
return 0;
}
if (changed_flags & NOTE_ABSOLUTE) {
kev->flags |= EV_ERROR;
kev->data = EINVAL;
return 0;
}
if ((error = filt_timervalidate(kev, &params)) != 0) {
kev->flags |= EV_ERROR;
kev->data = error;
return 0;
}
/* capture the new values used to compute deadline */
filt_timer_set_params(kn, &params);
kn->kn_sfflags = kev->fflags;
if (filt_timer_is_ready(kn)) {
filt_timerfire_immediate(kn);
return FILTER_ACTIVE | FILTER_UPDATE_REQ_QOS;
} else {
filt_timerarm(kn);
return FILTER_UPDATE_REQ_QOS;
}
}
/*
* filt_timerprocess - query state of knote and snapshot event data
*
* Determine if the timer has fired in the past, snapshot the state
* of the kevent for returning to user-space, and clear pending event
* counters for the next time.
*/
static int
filt_timerprocess(struct knote *kn, struct kevent_qos_s *kev)
{
uint32_t state = os_atomic_load(&kn->kn_hook32, relaxed);
/*
* filt_timerprocess is serialized with any filter routine except for
* filt_timerexpire which atomically does a TIMER_ARMED -> TIMER_FIRED
* transition, and on success, activates the knote.
*
* Hence, we don't need atomic modifications of the state, only to peek at
* whether we see any of the "FIRED" state, and if we do, it is safe to
* do simple state machine transitions.
*/
switch (state & TIMER_STATE_MASK) {
case TIMER_IDLE:
case TIMER_ARMED:
/*
* This can happen if a touch resets a timer that had fired
* without being processed
*/
return 0;
}
os_atomic_store(&kn->kn_hook32, state & ~TIMER_STATE_MASK, relaxed);
/*
* Copy out the interesting kevent state,
* but don't leak out the raw time calculations.
*
* TODO: potential enhancements - tell the user about:
* - deadline to which this timer thought it was expiring
* - return kn_sfflags in the fflags field so the client can know
* under what flags the timer fired
*/
knote_fill_kevent(kn, kev, 1);
kev->ext[0] = 0;
/* kev->ext[1] = 0; JMM - shouldn't we hide this too? */
if (kn->kn_sdata != 0) {
/*
* This is a 'repeating' timer, so we have to emit
* how many intervals expired between the arm
* and the process.
*
* A very strange style of interface, because
* this could easily be done in the client...
*/
uint64_t now;
if (kn->kn_sfflags & NOTE_MACH_CONTINUOUS_TIME) {
now = mach_continuous_time();
} else {
now = mach_absolute_time();
}
uint64_t first_deadline = kn->kn_ext[0];
uint64_t interval_abs = kn->kn_sdata;
uint64_t orig_arm_time = first_deadline - interval_abs;
assert(now > orig_arm_time);
assert(now > first_deadline);
uint64_t elapsed = now - orig_arm_time;
uint64_t num_fired = elapsed / interval_abs;
/*
* To reach this code, we must have seen the timer pop
* and be in repeating mode, so therefore it must have been
* more than 'interval' time since the attach or last
* successful touch.
*/
assert(num_fired > 0);
/* report how many intervals have elapsed to the user */
kev->data = (int64_t)num_fired;
/* We only need to re-arm the timer if it's not about to be destroyed */
if ((kn->kn_flags & EV_ONESHOT) == 0) {
/* fire at the end of the next interval */
uint64_t new_deadline = first_deadline + num_fired * interval_abs;
assert(new_deadline > now);
kn->kn_ext[0] = new_deadline;
/*
* This can't shortcut setting up the thread call, because
* knote_process deactivates EV_CLEAR knotes unconditionnally.
*/
filt_timerarm(kn);
}
}
return FILTER_ACTIVE;
}
SECURITY_READ_ONLY_EARLY(static struct filterops) timer_filtops = {
.f_extended_codes = true,
.f_attach = filt_timerattach,
.f_detach = filt_timerdetach,
.f_event = filt_bad_event,
.f_touch = filt_timertouch,
.f_process = filt_timerprocess,
};
#pragma mark user_filtops
static int
filt_userattach(struct knote *kn, __unused struct kevent_qos_s *kev)
{
if (kn->kn_sfflags & NOTE_TRIGGER) {
kn->kn_hook32 = FILTER_ACTIVE;
} else {
kn->kn_hook32 = 0;
}
return kn->kn_hook32;
}
static int
filt_usertouch(struct knote *kn, struct kevent_qos_s *kev)
{
uint32_t ffctrl;
int fflags;
ffctrl = kev->fflags & NOTE_FFCTRLMASK;
fflags = kev->fflags & NOTE_FFLAGSMASK;
switch (ffctrl) {
case NOTE_FFNOP:
break;
case NOTE_FFAND:
kn->kn_sfflags &= fflags;
break;
case NOTE_FFOR:
kn->kn_sfflags |= fflags;
break;
case NOTE_FFCOPY:
kn->kn_sfflags = fflags;
break;
}
kn->kn_sdata = kev->data;
if (kev->fflags & NOTE_TRIGGER) {
kn->kn_hook32 = FILTER_ACTIVE;
}
return (int)kn->kn_hook32;
}
static int
filt_userprocess(struct knote *kn, struct kevent_qos_s *kev)
{
int result = (int)kn->kn_hook32;
if (result) {
/* EVFILT_USER returns the data that was passed in */
knote_fill_kevent_with_sdata(kn, kev);
kev->fflags = kn->kn_sfflags;
if (kn->kn_flags & EV_CLEAR) {
/* knote_fill_kevent cleared kn_fflags */
kn->kn_hook32 = 0;
}
}
return result;
}
SECURITY_READ_ONLY_EARLY(static struct filterops) user_filtops = {
.f_extended_codes = true,
.f_attach = filt_userattach,
.f_detach = filt_no_detach,
.f_event = filt_bad_event,
.f_touch = filt_usertouch,
.f_process = filt_userprocess,
};
#pragma mark workloop_filtops
#define EPREEMPTDISABLED (-1)
static inline void
filt_wllock(struct kqworkloop *kqwl)
{
lck_spin_lock(&kqwl->kqwl_statelock);
}
static inline void
filt_wlunlock(struct kqworkloop *kqwl)
{
lck_spin_unlock(&kqwl->kqwl_statelock);
}
/*
* Returns true when the interlock for the turnstile is the workqueue lock
*
* When this is the case, all turnstiles operations are delegated
* to the workqueue subsystem.
*
* This is required because kqueue_threadreq_bind_prepost only holds the
* workqueue lock but needs to move the inheritor from the workloop turnstile
* away from the creator thread, so that this now fulfilled request cannot be
* picked anymore by other threads.
*/
static inline bool
filt_wlturnstile_interlock_is_workq(struct kqworkloop *kqwl)
{
return kqr_thread_requested_pending(&kqwl->kqwl_request);
}
static void
filt_wlupdate_inheritor(struct kqworkloop *kqwl, struct turnstile *ts,
turnstile_update_flags_t flags)
{
turnstile_inheritor_t inheritor = TURNSTILE_INHERITOR_NULL;
workq_threadreq_t kqr = &kqwl->kqwl_request;
/*
* binding to the workq should always happen through
* workq_kern_threadreq_update_inheritor()
*/
assert(!filt_wlturnstile_interlock_is_workq(kqwl));
if ((inheritor = kqwl->kqwl_owner)) {
flags |= TURNSTILE_INHERITOR_THREAD;
} else if ((inheritor = kqr_thread(kqr))) {
flags |= TURNSTILE_INHERITOR_THREAD;
}
turnstile_update_inheritor(ts, inheritor, flags);
}
#define EVFILT_WORKLOOP_EFAULT_RETRY_COUNT 100
#define FILT_WLATTACH 0
#define FILT_WLTOUCH 1
#define FILT_WLDROP 2
__result_use_check
static int
filt_wlupdate(struct kqworkloop *kqwl, struct knote *kn,
struct kevent_qos_s *kev, kq_index_t qos_index, int op)
{
user_addr_t uaddr = CAST_USER_ADDR_T(kev->ext[EV_EXTIDX_WL_ADDR]);
workq_threadreq_t kqr = &kqwl->kqwl_request;
thread_t cur_owner, new_owner, extra_thread_ref = THREAD_NULL;
kq_index_t cur_override = THREAD_QOS_UNSPECIFIED;
int efault_retry = EVFILT_WORKLOOP_EFAULT_RETRY_COUNT;
int action = KQWL_UTQ_NONE, error = 0;
bool wl_inheritor_updated = false, needs_wake = false;
uint64_t kdata = kev->ext[EV_EXTIDX_WL_VALUE];
uint64_t mask = kev->ext[EV_EXTIDX_WL_MASK];
uint64_t udata = 0;
struct turnstile *ts = TURNSTILE_NULL;
filt_wllock(kqwl);
again:
new_owner = cur_owner = kqwl->kqwl_owner;
/*
* Phase 1:
*
* If asked, load the uint64 value at the user provided address and compare
* it against the passed in mask and expected value.
*
* If NOTE_WL_DISCOVER_OWNER is specified, translate the loaded name as
* a thread reference.
*
* If NOTE_WL_END_OWNERSHIP is specified and the currently known owner is
* the current thread, then end ownership.
*
* Lastly decide whether we need to perform a QoS update.
*/
if (uaddr) {
/*
* Until <rdar://problem/24999882> exists,
* disabling preemption copyin forces any
* vm_fault we encounter to fail.
*/
error = copyin_atomic64(uaddr, &udata);
/*
* If we get EFAULT, drop locks, and retry.
* If we still get an error report it,
* else assume the memory has been faulted
* and attempt to copyin under lock again.
*/
switch (error) {
case 0:
break;
case EFAULT:
if (efault_retry-- > 0) {
filt_wlunlock(kqwl);
error = copyin_atomic64(uaddr, &udata);
filt_wllock(kqwl);
if (error == 0) {
goto again;
}
}
OS_FALLTHROUGH;
default:
goto out;
}
/* Update state as copied in. */
kev->ext[EV_EXTIDX_WL_VALUE] = udata;
if ((udata & mask) != (kdata & mask)) {
error = ESTALE;
} else if (kev->fflags & NOTE_WL_DISCOVER_OWNER) {
/*
* Decipher the owner port name, and translate accordingly.
* The low 2 bits were borrowed for other flags, so mask them off.
*
* Then attempt translation to a thread reference or fail.
*/
mach_port_name_t name = (mach_port_name_t)udata & ~0x3;
if (name != MACH_PORT_NULL) {
name = ipc_entry_name_mask(name);
extra_thread_ref = port_name_to_thread(name,
PORT_INTRANS_THREAD_IN_CURRENT_TASK);
if (extra_thread_ref == THREAD_NULL) {
error = EOWNERDEAD;
goto out;
}
new_owner = extra_thread_ref;
}
}
}
if ((kev->fflags & NOTE_WL_END_OWNERSHIP) && new_owner == current_thread()) {
new_owner = THREAD_NULL;
}
if (error == 0) {
if ((kev->fflags & NOTE_WL_THREAD_REQUEST) && (kev->flags & EV_DELETE)) {
action = KQWL_UTQ_SET_QOS_INDEX;
} else if (qos_index && kqr->tr_kq_qos_index != qos_index) {
action = KQWL_UTQ_SET_QOS_INDEX;
}
if (op == FILT_WLTOUCH) {
/*
* Save off any additional fflags/data we just accepted
* But only keep the last round of "update" bits we acted on which helps
* debugging a lot.
*/
kn->kn_sfflags &= ~NOTE_WL_UPDATES_MASK;
kn->kn_sfflags |= kev->fflags;
if (kev->fflags & NOTE_WL_SYNC_WAKE) {
needs_wake = (kn->kn_thread != THREAD_NULL);
}
} else if (op == FILT_WLDROP) {
if ((kn->kn_sfflags & (NOTE_WL_SYNC_WAIT | NOTE_WL_SYNC_WAKE)) ==
NOTE_WL_SYNC_WAIT) {
/*
* When deleting a SYNC_WAIT knote that hasn't been woken up
* explicitly, issue a wake up.
*/
kn->kn_sfflags |= NOTE_WL_SYNC_WAKE;
needs_wake = (kn->kn_thread != THREAD_NULL);
}
}
}
/*
* Phase 2:
*
* Commit ownership and QoS changes if any, possibly wake up waiters
*/
if (cur_owner == new_owner && action == KQWL_UTQ_NONE && !needs_wake) {
goto out;
}
kqlock(kqwl);
/* If already tracked as servicer, don't track as owner */
if (new_owner == kqr_thread(kqr)) {
new_owner = THREAD_NULL;
}
if (cur_owner != new_owner) {
kqwl->kqwl_owner = new_owner;
if (new_owner == extra_thread_ref) {
/* we just transfered this ref to kqwl_owner */
extra_thread_ref = THREAD_NULL;
}
cur_override = kqworkloop_override(kqwl);
if (new_owner) {
/* override it before we drop the old */
if (cur_override != THREAD_QOS_UNSPECIFIED) {
thread_add_kevent_override(new_owner, cur_override);
}
if (kqr_thread_requested_pending(kqr)) {
if (action == KQWL_UTQ_NONE) {
action = KQWL_UTQ_REDRIVE_EVENTS;
}
}
} else if (action == KQWL_UTQ_NONE &&
!kqr_thread_requested(kqr) &&
kqwl->kqwl_wakeup_qos) {
action = KQWL_UTQ_REDRIVE_EVENTS;
}
}
if (action != KQWL_UTQ_NONE) {
kqworkloop_update_threads_qos(kqwl, action, qos_index);
}
ts = kqwl->kqwl_turnstile;
if (cur_owner != new_owner && ts) {
if (action == KQWL_UTQ_REDRIVE_EVENTS) {
/*
* Note that when action is KQWL_UTQ_REDRIVE_EVENTS,
* the code went through workq_kern_threadreq_initiate()
* and the workqueue has set the inheritor already
*/
assert(filt_wlturnstile_interlock_is_workq(kqwl));
} else if (filt_wlturnstile_interlock_is_workq(kqwl)) {
workq_kern_threadreq_lock(kqwl->kqwl_p);
workq_kern_threadreq_update_inheritor(kqwl->kqwl_p, kqr, new_owner,
ts, TURNSTILE_IMMEDIATE_UPDATE);
workq_kern_threadreq_unlock(kqwl->kqwl_p);
if (!filt_wlturnstile_interlock_is_workq(kqwl)) {
/*
* If the workq is no longer the interlock, then
* workq_kern_threadreq_update_inheritor() has finished a bind
* and we need to fallback to the regular path.
*/
filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE);
}
wl_inheritor_updated = true;
} else {
filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE);
wl_inheritor_updated = true;
}
/*
* We need a turnstile reference because we are dropping the interlock
* and the caller has not called turnstile_prepare.
*/
if (wl_inheritor_updated) {
turnstile_reference(ts);
}
}
if (needs_wake && ts) {
waitq_wakeup64_thread(&ts->ts_waitq, knote_filt_wev64(kn),
kn->kn_thread, THREAD_AWAKENED);
if (op == FILT_WLATTACH || op == FILT_WLTOUCH) {
disable_preemption();
error = EPREEMPTDISABLED;
}
}
kqunlock(kqwl);
out:
/*
* Phase 3:
*
* Unlock and cleanup various lingering references and things.
*/
filt_wlunlock(kqwl);
#if CONFIG_WORKLOOP_DEBUG
KQWL_HISTORY_WRITE_ENTRY(kqwl, {
.updater = current_thread(),
.servicer = kqr_thread(kqr), /* Note: racy */
.old_owner = cur_owner,
.new_owner = new_owner,
.kev_ident = kev->ident,
.error = (int16_t)error,
.kev_flags = kev->flags,
.kev_fflags = kev->fflags,
.kev_mask = mask,
.kev_value = kdata,
.in_value = udata,
});
#endif // CONFIG_WORKLOOP_DEBUG
if (wl_inheritor_updated) {
turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_NOT_HELD);
turnstile_deallocate_safe(ts);
}
if (cur_owner && new_owner != cur_owner) {
if (cur_override != THREAD_QOS_UNSPECIFIED) {
thread_drop_kevent_override(cur_owner);
}
thread_deallocate_safe(cur_owner);
}
if (extra_thread_ref) {
thread_deallocate_safe(extra_thread_ref);
}
return error;
}
/*
* Remembers the last updated that came in from userspace for debugging reasons.
* - fflags is mirrored from the userspace kevent
* - ext[i, i != VALUE] is mirrored from the userspace kevent
* - ext[VALUE] is set to what the kernel loaded atomically
* - data is set to the error if any
*/
static inline void
filt_wlremember_last_update(struct knote *kn, struct kevent_qos_s *kev,
int error)
{
kn->kn_fflags = kev->fflags;
kn->kn_sdata = error;
memcpy(kn->kn_ext, kev->ext, sizeof(kev->ext));
}
static int
filt_wlupdate_sync_ipc(struct kqworkloop *kqwl, struct knote *kn,
struct kevent_qos_s *kev, int op)
{
user_addr_t uaddr = (user_addr_t) kev->ext[EV_EXTIDX_WL_ADDR];
uint64_t kdata = kev->ext[EV_EXTIDX_WL_VALUE];
uint64_t mask = kev->ext[EV_EXTIDX_WL_MASK];
uint64_t udata = 0;
int efault_retry = EVFILT_WORKLOOP_EFAULT_RETRY_COUNT;
int error = 0;
if (op == FILT_WLATTACH) {
(void)kqueue_alloc_turnstile(&kqwl->kqwl_kqueue);
} else if (uaddr == 0) {
return 0;
}
filt_wllock(kqwl);
again:
/*
* Do the debounce thing, the lock serializing the state is the knote lock.
*/
if (uaddr) {
/*
* Until <rdar://problem/24999882> exists,
* disabling preemption copyin forces any
* vm_fault we encounter to fail.
*/
error = copyin_atomic64(uaddr, &udata);
/*
* If we get EFAULT, drop locks, and retry.
* If we still get an error report it,
* else assume the memory has been faulted
* and attempt to copyin under lock again.
*/
switch (error) {
case 0:
break;
case EFAULT:
if (efault_retry-- > 0) {
filt_wlunlock(kqwl);
error = copyin_atomic64(uaddr, &udata);
filt_wllock(kqwl);
if (error == 0) {
goto again;
}
}
OS_FALLTHROUGH;
default:
goto out;
}
kev->ext[EV_EXTIDX_WL_VALUE] = udata;
kn->kn_ext[EV_EXTIDX_WL_VALUE] = udata;
if ((udata & mask) != (kdata & mask)) {
error = ESTALE;
goto out;
}
}
if (op == FILT_WLATTACH) {
error = filt_wlattach_sync_ipc(kn);
if (error == 0) {
disable_preemption();
error = EPREEMPTDISABLED;
}
}
out:
filt_wlunlock(kqwl);
return error;
}
static int
filt_wlattach(struct knote *kn, struct kevent_qos_s *kev)
{
struct kqueue *kq = knote_get_kq(kn);
struct kqworkloop *kqwl = (struct kqworkloop *)kq;
int error = 0, result = 0;
kq_index_t qos_index = 0;
if (__improbable((kq->kq_state & KQ_WORKLOOP) == 0)) {
error = ENOTSUP;
goto out;
}
uint32_t command = (kn->kn_sfflags & NOTE_WL_COMMANDS_MASK);
switch (command) {
case NOTE_WL_THREAD_REQUEST:
if (kn->kn_id != kqwl->kqwl_dynamicid) {
error = EINVAL;
goto out;
}
qos_index = _pthread_priority_thread_qos(kn->kn_qos);
if (qos_index == THREAD_QOS_UNSPECIFIED) {
error = ERANGE;
goto out;
}
if (kqwl->kqwl_request.tr_kq_qos_index) {
/*
* There already is a thread request, and well, you're only allowed
* one per workloop, so fail the attach.
*/
error = EALREADY;
goto out;
}
break;
case NOTE_WL_SYNC_WAIT:
case NOTE_WL_SYNC_WAKE:
if (kn->kn_id == kqwl->kqwl_dynamicid) {
error = EINVAL;
goto out;
}
if ((kn->kn_flags & EV_DISABLE) == 0) {
error = EINVAL;
goto out;
}
if (kn->kn_sfflags & NOTE_WL_END_OWNERSHIP) {
error = EINVAL;
goto out;
}
break;
case NOTE_WL_SYNC_IPC:
if ((kn->kn_flags & EV_DISABLE) == 0) {
error = EINVAL;
goto out;
}
if (kn->kn_sfflags & (NOTE_WL_UPDATE_QOS | NOTE_WL_DISCOVER_OWNER)) {
error = EINVAL;
goto out;
}
break;
default:
error = EINVAL;
goto out;
}
if (command == NOTE_WL_SYNC_IPC) {
error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLATTACH);
} else {
error = filt_wlupdate(kqwl, kn, kev, qos_index, FILT_WLATTACH);
}
if (error == EPREEMPTDISABLED) {
error = 0;
result = FILTER_THREADREQ_NODEFEER;
}
out:
if (error) {
/* If userland wants ESTALE to be hidden, fail the attach anyway */
if (error == ESTALE && (kn->kn_sfflags & NOTE_WL_IGNORE_ESTALE)) {
error = 0;
}
knote_set_error(kn, error);
return result;
}
if (command == NOTE_WL_SYNC_WAIT) {
return kevent_register_wait_prepare(kn, kev, result);
}
/* Just attaching the thread request successfully will fire it */
if (command == NOTE_WL_THREAD_REQUEST) {
/*
* Thread Request knotes need an explicit touch to be active again,
* so delivering an event needs to also consume it.
*/
kn->kn_flags |= EV_CLEAR;
return result | FILTER_ACTIVE;
}
return result;
}
static void __dead2
filt_wlwait_continue(void *parameter, wait_result_t wr)
{
struct _kevent_register *cont_args = parameter;
struct kqworkloop *kqwl = cont_args->kqwl;
kqlock(kqwl);
if (filt_wlturnstile_interlock_is_workq(kqwl)) {
workq_kern_threadreq_lock(kqwl->kqwl_p);
turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile, NULL, TURNSTILE_WORKLOOPS);
workq_kern_threadreq_unlock(kqwl->kqwl_p);
} else {
turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile, NULL, TURNSTILE_WORKLOOPS);
}
kqunlock(kqwl);
turnstile_cleanup();
if (wr == THREAD_INTERRUPTED) {
cont_args->kev.flags |= EV_ERROR;
cont_args->kev.data = EINTR;
} else if (wr != THREAD_AWAKENED) {
panic("Unexpected wait result: %d", wr);
}
kevent_register_wait_return(cont_args);
}
/*
* Called with the workloop mutex held, most of the time never returns as it
* calls filt_wlwait_continue through a continuation.
*/
static void __dead2
filt_wlpost_register_wait(struct uthread *uth, struct knote *kn,
struct _kevent_register *cont_args)
{
struct kqworkloop *kqwl = cont_args->kqwl;
workq_threadreq_t kqr = &kqwl->kqwl_request;
struct turnstile *ts;
bool workq_locked = false;
kqlock_held(kqwl);
if (filt_wlturnstile_interlock_is_workq(kqwl)) {
workq_kern_threadreq_lock(kqwl->kqwl_p);
workq_locked = true;
}
ts = turnstile_prepare((uintptr_t)kqwl, &kqwl->kqwl_turnstile,
TURNSTILE_NULL, TURNSTILE_WORKLOOPS);
if (workq_locked) {
workq_kern_threadreq_update_inheritor(kqwl->kqwl_p,
&kqwl->kqwl_request, kqwl->kqwl_owner, ts,
TURNSTILE_DELAYED_UPDATE);
if (!filt_wlturnstile_interlock_is_workq(kqwl)) {
/*
* if the interlock is no longer the workqueue lock,
* then we don't need to hold it anymore.
*/
workq_kern_threadreq_unlock(kqwl->kqwl_p);
workq_locked = false;
}
}
if (!workq_locked) {
/*
* If the interlock is the workloop's, then it's our responsibility to
* call update_inheritor, so just do it.
*/
filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_DELAYED_UPDATE);
}
thread_set_pending_block_hint(get_machthread(uth), kThreadWaitWorkloopSyncWait);
waitq_assert_wait64(&ts->ts_waitq, knote_filt_wev64(kn),
THREAD_ABORTSAFE, TIMEOUT_WAIT_FOREVER);
if (workq_locked) {
workq_kern_threadreq_unlock(kqwl->kqwl_p);
}
thread_t thread = kqwl->kqwl_owner ?: kqr_thread(kqr);
if (thread) {
thread_reference(thread);
}
kevent_register_wait_block(ts, thread, filt_wlwait_continue, cont_args);
}
/* called in stackshot context to report the thread responsible for blocking this thread */
void
kdp_workloop_sync_wait_find_owner(__assert_only thread_t thread,
event64_t event, thread_waitinfo_t *waitinfo)
{
struct knote *kn = (struct knote *)event;
zone_require(knote_zone, kn);
assert(kn->kn_thread == thread);
struct kqueue *kq = knote_get_kq(kn);
zone_require(kqworkloop_zone, kq);
assert(kq->kq_state & KQ_WORKLOOP);
struct kqworkloop *kqwl = (struct kqworkloop *)kq;
workq_threadreq_t kqr = &kqwl->kqwl_request;
thread_t kqwl_owner = kqwl->kqwl_owner;
if (kqwl_owner != THREAD_NULL) {
thread_require(kqwl_owner);
waitinfo->owner = thread_tid(kqwl->kqwl_owner);
} else if ((kqr->tr_state >= WORKQ_TR_STATE_BINDING) && (kqr->tr_thread != NULL)) {
thread_require(kqr->tr_thread);
waitinfo->owner = thread_tid(kqr->tr_thread);
} else if (kqr_thread_requested_pending(kqr)) { /* > idle, < bound */
waitinfo->owner = STACKSHOT_WAITOWNER_THREQUESTED;
} else {
waitinfo->owner = 0;
}
waitinfo->context = kqwl->kqwl_dynamicid;
}
static void
filt_wldetach(struct knote *kn)
{
if (kn->kn_sfflags & NOTE_WL_SYNC_IPC) {
filt_wldetach_sync_ipc(kn);
} else if (kn->kn_thread) {
kevent_register_wait_cleanup(kn);
}
}
static int
filt_wlvalidate_kev_flags(struct knote *kn, struct kevent_qos_s *kev,
thread_qos_t *qos_index)
{
uint32_t new_commands = kev->fflags & NOTE_WL_COMMANDS_MASK;
uint32_t sav_commands = kn->kn_sfflags & NOTE_WL_COMMANDS_MASK;
if ((kev->fflags & NOTE_WL_DISCOVER_OWNER) && (kev->flags & EV_DELETE)) {
return EINVAL;
}
if (kev->fflags & NOTE_WL_UPDATE_QOS) {
if (kev->flags & EV_DELETE) {
return EINVAL;
}
if (sav_commands != NOTE_WL_THREAD_REQUEST) {
return EINVAL;
}
if (!(*qos_index = _pthread_priority_thread_qos(kev->qos))) {
return ERANGE;
}
}
switch (new_commands) {
case NOTE_WL_THREAD_REQUEST:
/* thread requests can only update themselves */
if (sav_commands != NOTE_WL_THREAD_REQUEST) {
return EINVAL;
}
break;
case NOTE_WL_SYNC_WAIT:
if (kev->fflags & NOTE_WL_END_OWNERSHIP) {
return EINVAL;
}
goto sync_checks;
case NOTE_WL_SYNC_WAKE:
sync_checks:
if (!(sav_commands & (NOTE_WL_SYNC_WAIT | NOTE_WL_SYNC_WAKE))) {
return EINVAL;
}
if ((kev->flags & (EV_ENABLE | EV_DELETE)) == EV_ENABLE) {
return EINVAL;
}
break;
case NOTE_WL_SYNC_IPC:
if (sav_commands != NOTE_WL_SYNC_IPC) {
return EINVAL;
}
if ((kev->flags & (EV_ENABLE | EV_DELETE)) == EV_ENABLE) {
return EINVAL;
}
break;
default:
return EINVAL;
}
return 0;
}
static int
filt_wltouch(struct knote *kn, struct kevent_qos_s *kev)
{
struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn);
thread_qos_t qos_index = THREAD_QOS_UNSPECIFIED;
int result = 0;
int error = filt_wlvalidate_kev_flags(kn, kev, &qos_index);
if (error) {
goto out;
}
uint32_t command = kev->fflags & NOTE_WL_COMMANDS_MASK;
if (command == NOTE_WL_SYNC_IPC) {
error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLTOUCH);
} else {
error = filt_wlupdate(kqwl, kn, kev, qos_index, FILT_WLTOUCH);
filt_wlremember_last_update(kn, kev, error);
}
if (error == EPREEMPTDISABLED) {
error = 0;
result = FILTER_THREADREQ_NODEFEER;
}
out:
if (error) {
if (error == ESTALE && (kev->fflags & NOTE_WL_IGNORE_ESTALE)) {
/* If userland wants ESTALE to be hidden, do not activate */
return result;
}
kev->flags |= EV_ERROR;
kev->data = error;
return result;
}
if (command == NOTE_WL_SYNC_WAIT && !(kn->kn_sfflags & NOTE_WL_SYNC_WAKE)) {
return kevent_register_wait_prepare(kn, kev, result);
}
/* Just touching the thread request successfully will fire it */
if (command == NOTE_WL_THREAD_REQUEST) {
if (kev->fflags & NOTE_WL_UPDATE_QOS) {
result |= FILTER_UPDATE_REQ_QOS;
}
result |= FILTER_ACTIVE;
}
return result;
}
static bool
filt_wlallow_drop(struct knote *kn, struct kevent_qos_s *kev)
{
struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn);
int error = filt_wlvalidate_kev_flags(kn, kev, NULL);
if (error) {
goto out;
}
uint32_t command = (kev->fflags & NOTE_WL_COMMANDS_MASK);
if (command == NOTE_WL_SYNC_IPC) {
error = filt_wlupdate_sync_ipc(kqwl, kn, kev, FILT_WLDROP);
} else {
error = filt_wlupdate(kqwl, kn, kev, 0, FILT_WLDROP);
filt_wlremember_last_update(kn, kev, error);
}
assert(error != EPREEMPTDISABLED);
out:
if (error) {
if (error == ESTALE && (kev->fflags & NOTE_WL_IGNORE_ESTALE)) {
return false;
}
kev->flags |= EV_ERROR;
kev->data = error;
return false;
}
return true;
}
static int
filt_wlprocess(struct knote *kn, struct kevent_qos_s *kev)
{
struct kqworkloop *kqwl = (struct kqworkloop *)knote_get_kq(kn);
int rc = 0;
assert(kn->kn_sfflags & NOTE_WL_THREAD_REQUEST);
kqlock(kqwl);
if (kqwl->kqwl_owner) {
/*
* <rdar://problem/33584321> userspace sometimes due to events being
* delivered but not triggering a drain session can cause a process
* of the thread request knote.
*
* When that happens, the automatic deactivation due to process
* would swallow the event, so we have to activate the knote again.
*/
knote_activate(kqwl, kn, FILTER_ACTIVE);
} else {
#if DEBUG || DEVELOPMENT
if (kevent_debug_flags & KEVENT_PANIC_ON_NON_ENQUEUED_PROCESS) {
/*
* see src/queue_internal.h in libdispatch
*/
#define DISPATCH_QUEUE_ENQUEUED 0x1ull
user_addr_t addr = CAST_USER_ADDR_T(kn->kn_ext[EV_EXTIDX_WL_ADDR]);
task_t t = current_task();
uint64_t val;
if (addr && task_is_active(t) && !task_is_halting(t) &&
copyin_atomic64(addr, &val) == 0 &&
val && (val & DISPATCH_QUEUE_ENQUEUED) == 0 &&
(val >> 48) != 0xdead && (val >> 48) != 0 && (val >> 48) != 0xffff) {
panic("kevent: workloop %#016llx is not enqueued "
"(kn:%p dq_state:%#016llx kev.dq_state:%#016llx)",
kn->kn_udata, kn, val, kn->kn_ext[EV_EXTIDX_WL_VALUE]);
}
}
#endif
knote_fill_kevent(kn, kev, 0);
kev->fflags = kn->kn_sfflags;
rc |= FILTER_ACTIVE;
}
kqunlock(kqwl);
if (rc & FILTER_ACTIVE) {
workq_thread_set_max_qos(kqwl->kqwl_p, &kqwl->kqwl_request);
}
return rc;
}
SECURITY_READ_ONLY_EARLY(static struct filterops) workloop_filtops = {
.f_extended_codes = true,
.f_attach = filt_wlattach,
.f_detach = filt_wldetach,
.f_event = filt_bad_event,
.f_touch = filt_wltouch,
.f_process = filt_wlprocess,
.f_allow_drop = filt_wlallow_drop,
.f_post_register_wait = filt_wlpost_register_wait,
};
#pragma mark - kqueues allocation and deallocation
OS_NOINLINE
static void
kqworkloop_dealloc(struct kqworkloop *, bool hash_remove);
static inline bool
kqworkloop_try_retain(struct kqworkloop *kqwl)
{
return os_ref_retain_try_raw(&kqwl->kqwl_retains, NULL);
}
static inline void
kqworkloop_retain(struct kqworkloop *kqwl)
{
return os_ref_retain_raw(&kqwl->kqwl_retains, NULL);
}
OS_ALWAYS_INLINE
static inline void
kqueue_retain(kqueue_t kqu)
{
if (kqu.kq->kq_state & KQ_DYNAMIC) {
kqworkloop_retain(kqu.kqwl);
}
}
OS_ALWAYS_INLINE
static inline void
kqworkloop_release_live(struct kqworkloop *kqwl)
{
os_ref_release_live_raw(&kqwl->kqwl_retains, NULL);
}
OS_ALWAYS_INLINE
static inline void
kqueue_release_live(kqueue_t kqu)
{
if (kqu.kq->kq_state & KQ_DYNAMIC) {
kqworkloop_release_live(kqu.kqwl);
}
}
OS_ALWAYS_INLINE
static inline void
kqworkloop_release(struct kqworkloop *kqwl)
{
if (os_ref_release_raw(&kqwl->kqwl_retains, NULL) == 0) {
kqworkloop_dealloc(kqwl, true);
}
}
OS_ALWAYS_INLINE
static inline void
kqueue_release(kqueue_t kqu)
{
if (kqu.kq->kq_state & KQ_DYNAMIC) {
kqworkloop_release(kqu.kqwl);
}
}
/*!
* @function kqueue_destroy
*
* @brief
* Common part to all kqueue dealloc functions.
*/
OS_NOINLINE
static void
kqueue_destroy(kqueue_t kqu, zone_t zone)
{
lck_spin_destroy(&kqu.kq->kq_lock, &kq_lck_grp);
zfree(zone, kqu.kq);
}
/*!
* @function kqueue_init
*
* @brief
* Common part to all kqueue alloc functions.
*/
static kqueue_t
kqueue_init(kqueue_t kqu)
{
lck_spin_init(&kqu.kq->kq_lock, &kq_lck_grp, LCK_ATTR_NULL);
return kqu;
}
#pragma mark kqfile allocation and deallocation
/*!
* @function kqueue_dealloc
*
* @brief
* Detach all knotes from a kqfile and free it.
*
* @discussion
* 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)
{
KNOTE_LOCK_CTX(knlc);
struct proc *p = kq->kq_p;
struct filedesc *fdp = &p->p_fd;
struct knote *kn;
assert(kq && (kq->kq_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
proc_fdlock(p);
for (int i = 0; i < fdp->fd_knlistsize; i++) {
kn = SLIST_FIRST(&fdp->fd_knlist[i]);
while (kn != NULL) {
if (kq == knote_get_kq(kn)) {
kqlock(kq);
proc_fdunlock(p);
if (knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) {
knote_drop(kq, kn, &knlc);
}
proc_fdlock(p);
/* start over at beginning of list */
kn = SLIST_FIRST(&fdp->fd_knlist[i]);
continue;
}
kn = SLIST_NEXT(kn, kn_link);
}
}
knhash_lock(fdp);
proc_fdunlock(p);
if (fdp->fd_knhashmask != 0) {
for (int i = 0; i < (int)fdp->fd_knhashmask + 1; i++) {
kn = SLIST_FIRST(&fdp->fd_knhash[i]);
while (kn != NULL) {
if (kq == knote_get_kq(kn)) {
kqlock(kq);
knhash_unlock(fdp);
if (knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) {
knote_drop(kq, kn, &knlc);
}
knhash_lock(fdp);
/* start over at beginning of list */
kn = SLIST_FIRST(&fdp->fd_knhash[i]);
continue;
}
kn = SLIST_NEXT(kn, kn_link);
}
}
}
knhash_unlock(fdp);
kqueue_destroy(kq, kqfile_zone);
}
/*!
* @function kqueue_alloc
*
* @brief
* Allocate a kqfile.
*/
struct kqueue *
kqueue_alloc(struct proc *p)
{
struct kqfile *kqf;
/*
* kqfiles are created with kqueue() so we need to wait for
* the first kevent syscall to know which bit among
* KQ_KEV_{32,64,QOS} will be set in kqf_state
*/
kqf = zalloc_flags(kqfile_zone, Z_WAITOK | Z_ZERO);
kqf->kqf_p = p;
TAILQ_INIT_AFTER_BZERO(&kqf->kqf_queue);
TAILQ_INIT_AFTER_BZERO(&kqf->kqf_suppressed);
return kqueue_init(kqf).kq;
}
/*!
* @function kqueue_internal
*
* @brief
* Core implementation for kqueue and guarded_kqueue_np()
*/
int
kqueue_internal(struct proc *p, fp_initfn_t fp_init, void *initarg, int32_t *retval)
{
struct kqueue *kq;
struct fileproc *fp;
int fd, error;
error = falloc_withinit(p, current_cached_proc_cred(p),
vfs_context_current(), &fp, &fd, fp_init, initarg);
if (error) {
return error;
}
kq = kqueue_alloc(p);
if (kq == NULL) {
fp_free(p, fd, fp);
return ENOMEM;
}
fp->fp_flags |= FP_CLOEXEC | FP_CLOFORK;
fp->f_flag = FREAD | FWRITE;
fp->f_ops = &kqueueops;
fp_set_data(fp, kq);
fp->f_lflags |= FG_CONFINED;
proc_fdlock(p);
procfdtbl_releasefd(p, fd, NULL);
fp_drop(p, fd, fp, 1);
proc_fdunlock(p);
*retval = fd;
return error;
}
/*!
* @function kqueue
*
* @brief
* The kqueue syscall.
*/
int
kqueue(struct proc *p, __unused struct kqueue_args *uap, int32_t *retval)
{
return kqueue_internal(p, NULL, NULL, retval);
}
#pragma mark kqworkq allocation and deallocation
/*!
* @function kqworkq_dealloc
*
* @brief
* Deallocates a workqueue kqueue.
*
* @discussion
* This only happens at process death, or for races with concurrent
* kevent_get_kqwq calls, hence we don't have to care about knotes referencing
* this kqueue, either there are none, or someone else took care of them.
*/
void
kqworkq_dealloc(struct kqworkq *kqwq)
{
kqueue_destroy(kqwq, kqworkq_zone);
}
/*!
* @function kqworkq_alloc
*
* @brief
* Allocates a workqueue kqueue.
*
* @discussion
* This is the slow path of kevent_get_kqwq.
* This takes care of making sure procs have a single workq kqueue.
*/
OS_NOINLINE
static struct kqworkq *
kqworkq_alloc(struct proc *p, unsigned int flags)
{
struct kqworkq *kqwq, *tmp;
kqwq = zalloc_flags(kqworkq_zone, Z_WAITOK | Z_ZERO);
assert((flags & KEVENT_FLAG_LEGACY32) == 0);
if (flags & KEVENT_FLAG_LEGACY64) {
kqwq->kqwq_state = KQ_WORKQ | KQ_KEV64;
} else {
kqwq->kqwq_state = KQ_WORKQ | KQ_KEV_QOS;
}
kqwq->kqwq_p = p;
for (int i = 0; i < KQWQ_NBUCKETS; i++) {
TAILQ_INIT_AFTER_BZERO(&kqwq->kqwq_queue[i]);
TAILQ_INIT_AFTER_BZERO(&kqwq->kqwq_suppressed[i]);
}
for (int i = 0; i < KQWQ_NBUCKETS; i++) {
/*
* Because of how the bucketized system works, we mix overcommit
* sources with not overcommit: each time we move a knote from
* one bucket to the next due to overrides, we'd had to track
* overcommitness, and it's really not worth it in the workloop
* enabled world that track this faithfully.
*
* Incidentally, this behaves like the original manager-based
* kqwq where event delivery always happened (hence is
* "overcommit")
*/
kqwq->kqwq_request[i].tr_state = WORKQ_TR_STATE_IDLE;
kqwq->kqwq_request[i].tr_flags = WORKQ_TR_FLAG_KEVENT;
if (i != KQWQ_QOS_MANAGER) {
kqwq->kqwq_request[i].tr_flags |= WORKQ_TR_FLAG_OVERCOMMIT;
}
kqwq->kqwq_request[i].tr_kq_qos_index = (kq_index_t)i + 1;
}
kqueue_init(kqwq);
if (!os_atomic_cmpxchgv(&p->p_fd.fd_wqkqueue, NULL, kqwq, &tmp, release)) {
kqworkq_dealloc(kqwq);
return tmp;
}
return kqwq;
}
#pragma mark kqworkloop allocation and deallocation
#define KQ_HASH(val, mask) (((val) ^ (val >> 8)) & (mask))
#define CONFIG_KQ_HASHSIZE CONFIG_KN_HASHSIZE
OS_ALWAYS_INLINE
static inline void
kqhash_lock(struct filedesc *fdp)
{
lck_mtx_lock_spin_always(&fdp->fd_kqhashlock);
}
OS_ALWAYS_INLINE
static inline void
kqhash_unlock(struct filedesc *fdp)
{
lck_mtx_unlock(&fdp->fd_kqhashlock);
}
OS_ALWAYS_INLINE
static inline void
kqworkloop_hash_insert_locked(struct filedesc *fdp, kqueue_id_t id,
struct kqworkloop *kqwl)
{
struct kqwllist *list = &fdp->fd_kqhash[KQ_HASH(id, fdp->fd_kqhashmask)];
LIST_INSERT_HEAD(list, kqwl, kqwl_hashlink);
}
OS_ALWAYS_INLINE
static inline struct kqworkloop *
kqworkloop_hash_lookup_locked(struct filedesc *fdp, kqueue_id_t id)
{
struct kqwllist *list = &fdp->fd_kqhash[KQ_HASH(id, fdp->fd_kqhashmask)];
struct kqworkloop *kqwl;
LIST_FOREACH(kqwl, list, kqwl_hashlink) {
if (kqwl->kqwl_dynamicid == id) {
return kqwl;
}
}
return NULL;
}
static struct kqworkloop *
kqworkloop_hash_lookup_and_retain(struct filedesc *fdp, kqueue_id_t kq_id)
{
struct kqworkloop *kqwl = NULL;
kqhash_lock(fdp);
if (__probable(fdp->fd_kqhash)) {
kqwl = kqworkloop_hash_lookup_locked(fdp, kq_id);
if (kqwl && !kqworkloop_try_retain(kqwl)) {
kqwl = NULL;
}
}
kqhash_unlock(fdp);
return kqwl;
}
OS_NOINLINE
static void
kqworkloop_hash_init(struct filedesc *fdp)
{
struct kqwllist *alloc_hash;
u_long alloc_mask;
kqhash_unlock(fdp);
alloc_hash = hashinit(CONFIG_KQ_HASHSIZE, M_KQUEUE, &alloc_mask);
kqhash_lock(fdp);
/* See if we won the race */
if (__probable(fdp->fd_kqhashmask == 0)) {
fdp->fd_kqhash = alloc_hash;
fdp->fd_kqhashmask = alloc_mask;
} else {
kqhash_unlock(fdp);
hashdestroy(alloc_hash, M_KQUEUE, alloc_mask);
kqhash_lock(fdp);
}
}
/*
* kqueue iotier override is only supported for kqueue that has
* only one port as a mach port source. Updating the iotier
* override on the mach port source will update the override
* on kqueue as well. Since kqueue with iotier override will
* only have one port attached, there is no logic for saturation
* like qos override, the iotier override of mach port source
* would be reflected in kevent iotier override.
*/
void
kqueue_set_iotier_override(kqueue_t kqu, uint8_t iotier_override)
{
if (!(kqu.kq->kq_state & KQ_WORKLOOP)) {
return;
}
struct kqworkloop *kqwl = kqu.kqwl;
os_atomic_store(&kqwl->kqwl_iotier_override, iotier_override, relaxed);
}
uint8_t
kqueue_get_iotier_override(kqueue_t kqu)
{
if (!(kqu.kq->kq_state & KQ_WORKLOOP)) {
return THROTTLE_LEVEL_END;
}
struct kqworkloop *kqwl = kqu.kqwl;
return os_atomic_load(&kqwl->kqwl_iotier_override, relaxed);
}
#if CONFIG_PREADOPT_TG
/*
* This function is called with a borrowed reference on the thread group without
* kq lock held with the mqueue lock held. It may or may not have the knote lock
* (called from both fevent as well as fattach/ftouch). Upon success, an
* additional reference on the TG is taken
*/
void
kqueue_set_preadopted_thread_group(kqueue_t kqu, struct thread_group *tg, thread_qos_t qos)
{
if (!(kqu.kq->kq_state & KQ_WORKLOOP)) {
KDBG_RELEASE(MACHDBG_CODE(DBG_MACH_THREAD_GROUP, MACH_THREAD_GROUP_PREADOPT_NA),
(uintptr_t)thread_tid(current_thread()), 0, 0, 0);
return;
}
struct kqworkloop *kqwl = kqu.kqwl;
assert(qos < THREAD_QOS_LAST);
thread_group_retain(tg);
thread_group_qos_t old_tg; thread_group_qos_t new_tg;
int ret = os_atomic_rmw_loop(&kqwl->kqwl_preadopt_tg, old_tg, new_tg, relaxed, {
if (!KQWL_CAN_ADOPT_PREADOPT_TG(old_tg)) {
os_atomic_rmw_loop_give_up(break);
}
if (old_tg != KQWL_PREADOPTED_TG_NULL) {
/*
* Note that old_tg could be a NULL TG pointer but with a QoS
* set. See also workq_thread_reset_pri.
*
* Compare the QoS of existing preadopted tg with new one and
* only overwrite the thread group if we have one with a higher
* QoS.
*/
thread_qos_t existing_qos = KQWL_GET_PREADOPTED_TG_QOS(old_tg);
if (existing_qos >= qos) {
os_atomic_rmw_loop_give_up(break);
}
}
// Transfer the ref taken earlier in the function to the kqwl
new_tg = KQWL_ENCODE_PREADOPTED_TG_QOS(tg, qos);
});
if (ret) {
KQWL_PREADOPT_TG_HISTORY_WRITE_ENTRY(kqwl, KQWL_PREADOPT_OP_INCOMING_IPC, old_tg, tg);
if (KQWL_HAS_VALID_PREADOPTED_TG(old_tg)) {
thread_group_deallocate_safe(KQWL_GET_PREADOPTED_TG(old_tg));
}
os_atomic_store(&kqwl->kqwl_preadopt_tg_needs_redrive, KQWL_PREADOPT_TG_NEEDS_REDRIVE, release);
} else {
// We failed to write to the kqwl_preadopt_tg, drop the ref we took
// earlier in the function
thread_group_deallocate_safe(tg);
}
}
/*
* Called from fprocess of EVFILT_MACHPORT without the kqueue lock held.
*/
bool
kqueue_process_preadopt_thread_group(thread_t thread, struct kqueue *kq, struct thread_group *tg)
{
bool success = false;
if (kq->kq_state & KQ_WORKLOOP) {
struct kqworkloop *kqwl = (struct kqworkloop *) kq;
thread_group_qos_t old_tg;
success = os_atomic_cmpxchgv(&kqwl->kqwl_preadopt_tg,
KQWL_PREADOPTED_TG_SENTINEL, KQWL_PREADOPTED_TG_PROCESSED,
&old_tg, relaxed);
if (success) {
thread_set_preadopt_thread_group(thread, tg);
} else if (KQWL_HAS_PERMANENT_PREADOPTED_TG(old_tg)) {
/*
* Technically the following set_preadopt should be a no-op since this
* servicer thread preadopts kqwl's permanent tg at bind time.
* See kqueue_threadreq_bind.
*/
thread_set_preadopt_thread_group(thread, KQWL_GET_PREADOPTED_TG(old_tg));
} else {
assert(old_tg == KQWL_PREADOPTED_TG_PROCESSED ||
old_tg == KQWL_PREADOPTED_TG_NEVER);
}
}
return success;
}
#endif
/*!
* @function kqworkloop_dealloc
*
* @brief
* Deallocates a workloop kqueue.
*
* @discussion
* Knotes hold references on the workloop, so we can't really reach this
* function unless all of these are already gone.
*
* Nothing locked on entry or exit.
*
* @param hash_remove
* Whether to remove the workloop from its hash table.
*/
static void
kqworkloop_dealloc(struct kqworkloop *kqwl, bool hash_remove)
{
thread_t cur_owner;
cur_owner = kqwl->kqwl_owner;
if (cur_owner) {
if (kqworkloop_override(kqwl) != THREAD_QOS_UNSPECIFIED) {
thread_drop_kevent_override(cur_owner);
}
thread_deallocate(cur_owner);
kqwl->kqwl_owner = THREAD_NULL;
}
if (kqwl->kqwl_state & KQ_HAS_TURNSTILE) {
struct turnstile *ts;
turnstile_complete((uintptr_t)kqwl, &kqwl->kqwl_turnstile,
&ts, TURNSTILE_WORKLOOPS);
turnstile_cleanup();
turnstile_deallocate(ts);
}
if (hash_remove) {
struct filedesc *fdp = &kqwl->kqwl_p->p_fd;
kqhash_lock(fdp);
LIST_REMOVE(kqwl, kqwl_hashlink);
#if CONFIG_PROC_RESOURCE_LIMITS
fdp->num_kqwls--;
#endif
kqhash_unlock(fdp);
}
#if CONFIG_PREADOPT_TG
thread_group_qos_t tg = os_atomic_load(&kqwl->kqwl_preadopt_tg, relaxed);
if (KQWL_HAS_VALID_PREADOPTED_TG(tg)) {
thread_group_release(KQWL_GET_PREADOPTED_TG(tg));
}
#endif
assert(TAILQ_EMPTY(&kqwl->kqwl_suppressed));
assert(kqwl->kqwl_owner == THREAD_NULL);
assert(kqwl->kqwl_turnstile == TURNSTILE_NULL);
lck_spin_destroy(&kqwl->kqwl_statelock, &kq_lck_grp);
kqueue_destroy(kqwl, kqworkloop_zone);
}
/*!
* @function kqworkloop_init
*
* @brief
* Initializes an allocated kqworkloop.
*/
static void
kqworkloop_init(struct kqworkloop *kqwl, proc_t p,
kqueue_id_t id, workq_threadreq_param_t *trp
#if CONFIG_PREADOPT_TG
, struct thread_group *trp_permanent_preadopt_tg
#endif
)
{
kqwl->kqwl_state = KQ_WORKLOOP | KQ_DYNAMIC | KQ_KEV_QOS;
os_ref_init_raw(&kqwl->kqwl_retains, NULL);
kqwl->kqwl_dynamicid = id;
kqwl->kqwl_p = p;
if (trp) {
kqwl->kqwl_params = trp->trp_value;
}
workq_tr_flags_t tr_flags = WORKQ_TR_FLAG_WORKLOOP;
if (trp) {
if (trp->trp_flags & TRP_PRIORITY) {
tr_flags |= WORKQ_TR_FLAG_WL_OUTSIDE_QOS;
}
if (trp->trp_flags) {
tr_flags |= WORKQ_TR_FLAG_WL_PARAMS;
}
}
kqwl->kqwl_request.tr_state = WORKQ_TR_STATE_IDLE;
kqwl->kqwl_request.tr_flags = tr_flags;
os_atomic_store(&kqwl->kqwl_iotier_override, (uint8_t)THROTTLE_LEVEL_END, relaxed);
#if CONFIG_PREADOPT_TG
if (trp_permanent_preadopt_tg) {
/*
* This kqwl is permanently configured with a thread group.
* By using THREAD_QOS_LAST, we make sure kqueue_set_preadopted_thread_group
* has no effect on kqwl_preadopt_tg. At this point, +1 ref on
* trp_permanent_preadopt_tg is transferred to the kqwl.
*/
thread_group_qos_t kqwl_preadopt_tg;
kqwl_preadopt_tg = KQWL_ENCODE_PERMANENT_PREADOPTED_TG(trp_permanent_preadopt_tg);
os_atomic_store(&kqwl->kqwl_preadopt_tg, kqwl_preadopt_tg, relaxed);
} else if (task_is_app(current_task())) {
/*
* Not a specially preconfigured kqwl so it is open to participate in sync IPC
* thread group preadoption; but, apps will never adopt a thread group that
* is not their own. This is a gross hack to simulate the post-process that
* is done in the voucher subsystem today for thread groups.
*/
os_atomic_store(&kqwl->kqwl_preadopt_tg, KQWL_PREADOPTED_TG_NEVER, relaxed);
}
#endif
for (int i = 0; i < KQWL_NBUCKETS; i++) {
TAILQ_INIT_AFTER_BZERO(&kqwl->kqwl_queue[i]);
}
TAILQ_INIT_AFTER_BZERO(&kqwl->kqwl_suppressed);
lck_spin_init(&kqwl->kqwl_statelock, &kq_lck_grp, LCK_ATTR_NULL);
kqueue_init(kqwl);
}
#if CONFIG_PROC_RESOURCE_LIMITS
void
kqworkloop_check_limit_exceeded(struct filedesc *fdp)
{
int num_kqwls = fdp->num_kqwls;
if (!kqwl_above_soft_limit_notified(fdp) && fdp->kqwl_dyn_soft_limit > 0 &&
num_kqwls > fdp->kqwl_dyn_soft_limit) {
kqwl_above_soft_limit_send_notification(fdp);
act_set_astproc_resource(current_thread());
} else if (!kqwl_above_hard_limit_notified(fdp) && fdp->kqwl_dyn_hard_limit > 0
&& num_kqwls > fdp->kqwl_dyn_hard_limit) {
kqwl_above_hard_limit_send_notification(fdp);
act_set_astproc_resource(current_thread());
}
}
#endif
/*!
* @function kqworkloop_get_or_create
*
* @brief
* Wrapper around kqworkloop_init that handles the uniquing of workloops.
*
* @returns
* 0: success
* EINVAL: invalid parameters
* EEXIST: KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST is set and a collision exists.
* ENOENT: KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST is set and the entry wasn't found.
* ENOMEM: allocation failed
*/
static int
kqworkloop_get_or_create(struct proc *p, kqueue_id_t id,
workq_threadreq_param_t *trp,
#if CONFIG_PREADOPT_TG
struct thread_group *trp_permanent_preadopt_tg,
#endif
unsigned int flags, struct kqworkloop **kqwlp)
{
struct filedesc *fdp = &p->p_fd;
struct kqworkloop *alloc_kqwl = NULL;
struct kqworkloop *kqwl = NULL;
int error = 0;
assert(!trp || (flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST));
if (id == 0 || id == (kqueue_id_t)-1) {
return EINVAL;
}
for (;;) {
kqhash_lock(fdp);
if (__improbable(fdp->fd_kqhash == NULL)) {
kqworkloop_hash_init(fdp);
}
kqwl = kqworkloop_hash_lookup_locked(fdp, id);
if (kqwl) {
if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST)) {
/*
* If MUST_NOT_EXIST was passed, even if we would have failed
* the try_retain, it could have gone the other way, and
* userspace can't tell. Let'em fix their race.
*/
error = EEXIST;
break;
}
if (__probable(kqworkloop_try_retain(kqwl))) {
/*
* This is a valid live workloop !
*/
*kqwlp = kqwl;
error = 0;
break;
}
}
if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST)) {
error = ENOENT;
break;
}
/*
* We didn't find what we were looking for.
*
* If this is the second time we reach this point (alloc_kqwl != NULL),
* then we're done.
*
* If this is the first time we reach this point (alloc_kqwl == NULL),
* then try to allocate one without blocking.
*/
if (__probable(alloc_kqwl == NULL)) {
alloc_kqwl = zalloc_flags(kqworkloop_zone, Z_NOWAIT | Z_ZERO);
}
if (__probable(alloc_kqwl)) {
#if CONFIG_PROC_RESOURCE_LIMITS
fdp->num_kqwls++;
kqworkloop_check_limit_exceeded(fdp);
#endif
kqworkloop_init(alloc_kqwl, p, id, trp
#if CONFIG_PREADOPT_TG
, trp_permanent_preadopt_tg
#endif
);
kqworkloop_hash_insert_locked(fdp, id, alloc_kqwl);
kqhash_unlock(fdp);
*kqwlp = alloc_kqwl;
return 0;
}
/*
* We have to block to allocate a workloop, drop the lock,
* allocate one, but then we need to retry lookups as someone
* else could race with us.
*/
kqhash_unlock(fdp);
alloc_kqwl = zalloc_flags(kqworkloop_zone, Z_WAITOK | Z_ZERO);
}
kqhash_unlock(fdp);
if (__improbable(alloc_kqwl)) {
zfree(kqworkloop_zone, alloc_kqwl);
}
return error;
}
#pragma mark - knotes
static int
filt_no_attach(struct knote *kn, __unused struct kevent_qos_s *kev)
{
knote_set_error(kn, ENOTSUP);
return 0;
}
static void
filt_no_detach(__unused struct knote *kn)
{
}
static int __dead2
filt_bad_event(struct knote *kn, long hint)
{
panic("%s[%d](%p, %ld)", __func__, kn->kn_filter, kn, hint);
}
static int __dead2
filt_bad_touch(struct knote *kn, struct kevent_qos_s *kev)
{
panic("%s[%d](%p, %p)", __func__, kn->kn_filter, kn, kev);
}
static int __dead2
filt_bad_process(struct knote *kn, struct kevent_qos_s *kev)
{
panic("%s[%d](%p, %p)", __func__, kn->kn_filter, kn, kev);
}
/*
* knotes_dealloc - detach all knotes for the process and drop them
*
* Process is in such a state that it will not try to allocate
* any more knotes during this process (stopped for exit or exec).
*/
void
knotes_dealloc(proc_t p)
{
struct filedesc *fdp = &p->p_fd;
struct kqueue *kq;
struct knote *kn;
struct klist *kn_hash = NULL;
u_long kn_hashmask;
int i;
proc_fdlock(p);
/* Close all the fd-indexed knotes up front */
if (fdp->fd_knlistsize > 0) {
for (i = 0; i < fdp->fd_knlistsize; i++) {
while ((kn = SLIST_FIRST(&fdp->fd_knlist[i])) != NULL) {
kq = knote_get_kq(kn);
kqlock(kq);
proc_fdunlock(p);
knote_drop(kq, kn, NULL);
proc_fdlock(p);
}
}
/* free the table */
kfree_type(struct klist, fdp->fd_knlistsize, fdp->fd_knlist);
}
fdp->fd_knlistsize = 0;
proc_fdunlock(p);
knhash_lock(fdp);
/* Clean out all the hashed knotes as well */
if (fdp->fd_knhashmask != 0) {
for (i = 0; i <= (int)fdp->fd_knhashmask; i++) {
while ((kn = SLIST_FIRST(&fdp->fd_knhash[i])) != NULL) {
kq = knote_get_kq(kn);
kqlock(kq);
knhash_unlock(fdp);
knote_drop(kq, kn, NULL);
knhash_lock(fdp);
}
}
kn_hash = fdp->fd_knhash;
kn_hashmask = fdp->fd_knhashmask;
fdp->fd_knhashmask = 0;
fdp->fd_knhash = NULL;
}
knhash_unlock(fdp);
if (kn_hash) {
hashdestroy(kn_hash, M_KQUEUE, kn_hashmask);
}
}
/*
* kqworkloops_dealloc - rebalance retains on kqworkloops created with
* scheduling parameters
*
* Process is in such a state that it will not try to allocate
* any more kqs or knotes during this process (stopped for exit or exec).
*/
void
kqworkloops_dealloc(proc_t p)
{
struct filedesc *fdp = &p->p_fd;
struct kqworkloop *kqwl, *kqwln;
struct kqwllist tofree;
if (!fdt_flag_test(fdp, FD_WORKLOOP)) {
return;
}
kqhash_lock(fdp);
if (fdp->fd_kqhashmask == 0) {
kqhash_unlock(fdp);
return;
}
LIST_INIT(&tofree);
for (size_t i = 0; i <= fdp->fd_kqhashmask; i++) {
LIST_FOREACH_SAFE(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink, kqwln) {
#if CONFIG_PREADOPT_TG
/*
* kqworkloops that have scheduling parameters have an
* implicit retain from kqueue_workloop_ctl that needs
* to be balanced on process exit.
*/
__assert_only thread_group_qos_t preadopt_tg;
preadopt_tg = os_atomic_load(&kqwl->kqwl_preadopt_tg, relaxed);
#endif
assert(kqwl->kqwl_params
#if CONFIG_PREADOPT_TG
|| KQWL_HAS_PERMANENT_PREADOPTED_TG(preadopt_tg)
#endif
);
LIST_REMOVE(kqwl, kqwl_hashlink);
LIST_INSERT_HEAD(&tofree, kqwl, kqwl_hashlink);
}
}
#if CONFIG_PROC_RESOURCE_LIMITS
fdp->num_kqwls = 0;
#endif
kqhash_unlock(fdp);
LIST_FOREACH_SAFE(kqwl, &tofree, kqwl_hashlink, kqwln) {
uint32_t ref = os_ref_get_count_raw(&kqwl->kqwl_retains);
if (ref != 1) {
panic("kq(%p) invalid refcount %d", kqwl, ref);
}
kqworkloop_dealloc(kqwl, false);
}
}
static int
kevent_register_validate_priority(struct kqueue *kq, struct knote *kn,
struct kevent_qos_s *kev)
{
/* We don't care about the priority of a disabled or deleted knote */
if (kev->flags & (EV_DISABLE | EV_DELETE)) {
return 0;
}
if (kq->kq_state & KQ_WORKLOOP) {
/*
* Workloops need valid priorities with a QOS (excluding manager) for
* any enabled knote.
*
* When it is pre-existing, just make sure it has a valid QoS as
* kevent_register() will not use the incoming priority (filters who do
* have the responsibility to validate it again, see filt_wltouch).
*
* If the knote is being made, validate the incoming priority.
*/
if (!_pthread_priority_thread_qos(kn ? kn->kn_qos : kev->qos)) {
return ERANGE;
}
}
return 0;
}
/*
* Prepare a filter for waiting after register.
*
* The f_post_register_wait hook will be called later by kevent_register()
* and should call kevent_register_wait_block()
*/
static int
kevent_register_wait_prepare(struct knote *kn, struct kevent_qos_s *kev, int rc)
{
thread_t thread = current_thread();
assert(knote_fops(kn)->f_extended_codes);
if (kn->kn_thread == NULL) {
thread_reference(thread);
kn->kn_thread = thread;
} else if (kn->kn_thread != thread) {
/*
* kn_thread may be set from a previous aborted wait
* However, it has to be from the same thread.
*/
kev->flags |= EV_ERROR;
kev->data = EXDEV;
return 0;
}
return FILTER_REGISTER_WAIT | rc;
}
/*
* Cleanup a kevent_register_wait_prepare() effect for threads that have been
* aborted instead of properly woken up with thread_wakeup_thread().
*/
static void
kevent_register_wait_cleanup(struct knote *kn)
{
thread_t thread = kn->kn_thread;
kn->kn_thread = NULL;
thread_deallocate(thread);
}
/*
* Must be called at the end of a f_post_register_wait call from a filter.
*/
static void
kevent_register_wait_block(struct turnstile *ts, thread_t thread,
thread_continue_t cont, struct _kevent_register *cont_args)
{
turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_HELD);
kqunlock(cont_args->kqwl);
cont_args->handoff_thread = thread;
thread_handoff_parameter(thread, cont, cont_args, THREAD_HANDOFF_NONE);
}
/*
* Called by Filters using a f_post_register_wait to return from their wait.
*/
static void
kevent_register_wait_return(struct _kevent_register *cont_args)
{
struct kqworkloop *kqwl = cont_args->kqwl;
struct kevent_qos_s *kev = &cont_args->kev;
int error = 0;
if (cont_args->handoff_thread) {
thread_deallocate(cont_args->handoff_thread);
}
if (kev->flags & (EV_ERROR | EV_RECEIPT)) {
if ((kev->flags & EV_ERROR) == 0) {
kev->flags |= EV_ERROR;
kev->data = 0;
}
error = kevent_modern_copyout(kev, &cont_args->ueventlist);
if (error == 0) {
cont_args->eventout++;
}
}
kqworkloop_release(kqwl);
if (error == 0) {
*(int32_t *)&current_uthread()->uu_rval = cont_args->eventout;
}
unix_syscall_return(error);
}
/*
* 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 kevent_qos_s *kev,
struct knote **kn_out)
{
struct proc *p = kq->kq_p;
const struct filterops *fops;
struct knote *kn = NULL;
int result = 0, error = 0;
unsigned short kev_flags = kev->flags;
KNOTE_LOCK_CTX(knlc);
if (__probable(kev->filter < 0 && kev->filter + EVFILT_SYSCOUNT >= 0)) {
fops = sysfilt_ops[~kev->filter]; /* to 0-base index */
} else {
error = EINVAL;
goto out;
}
/* restrict EV_VANISHED to adding udata-specific dispatch kevents */
if (__improbable((kev->flags & EV_VANISHED) &&
(kev->flags & (EV_ADD | EV_DISPATCH2)) != (EV_ADD | EV_DISPATCH2))) {
error = EINVAL;
goto out;
}
/* Simplify the flags - delete and disable overrule */
if (kev->flags & EV_DELETE) {
kev->flags &= ~EV_ADD;
}
if (kev->flags & EV_DISABLE) {
kev->flags &= ~EV_ENABLE;
}
if (kq->kq_state & KQ_WORKLOOP) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_REGISTER),
((struct kqworkloop *)kq)->kqwl_dynamicid,
kev->udata, kev->flags, kev->filter);
} else if (kq->kq_state & KQ_WORKQ) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_REGISTER),
0, kev->udata, kev->flags, kev->filter);
} else {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_REGISTER),
VM_KERNEL_UNSLIDE_OR_PERM(kq),
kev->udata, kev->flags, kev->filter);
}
restart:
/* find the matching knote from the fd tables/hashes */
kn = kq_find_knote_and_kq_lock(kq, kev, fops->f_isfd, p);
error = kevent_register_validate_priority(kq, kn, kev);
result = 0;
if (error) {
if (kn) {
kqunlock(kq);
}
goto out;
}
if (kn == NULL && (kev->flags & EV_ADD) == 0) {
/*
* No knote found, EV_ADD wasn't specified
*/
if ((kev_flags & EV_ADD) && (kev_flags & EV_DELETE) &&
(kq->kq_state & KQ_WORKLOOP)) {
/*
* For workloops, understand EV_ADD|EV_DELETE as a "soft" delete
* that doesn't care about ENOENT, so just pretend the deletion
* happened.
*/
} else {
error = ENOENT;
}
goto out;
} else if (kn == NULL) {
/*
* No knote found, need to attach a new one (attach)
*/
struct fileproc *knote_fp = NULL;
/* grab a file reference for the new knote */
if (fops->f_isfd) {
if ((error = fp_lookup(p, (int)kev->ident, &knote_fp, 0)) != 0) {
goto out;
}
}
kn = knote_alloc();
kn->kn_fp = knote_fp;
kn->kn_is_fd = fops->f_isfd;
kn->kn_kq_packed = VM_PACK_POINTER((vm_offset_t)kq, KNOTE_KQ_PACKED);
kn->kn_status = 0;
/* was vanish support requested */
if (kev->flags & EV_VANISHED) {
kev->flags &= ~EV_VANISHED;
kn->kn_status |= KN_REQVANISH;
}
/* snapshot matching/dispatching protocol flags into knote */
if (kev->flags & EV_DISABLE) {
kn->kn_status |= KN_DISABLED;
}
/*
* copy the kevent state into knote
* protocol is that fflags and data
* are saved off, and cleared before
* calling the attach routine.
*
* - kn->kn_sfflags aliases with kev->xflags
* - kn->kn_sdata aliases with kev->data
* - kn->kn_filter is the top 8 bits of kev->filter
*/
kn->kn_kevent = *(struct kevent_internal_s *)kev;
kn->kn_sfflags = kev->fflags;
kn->kn_filtid = (uint8_t)~kev->filter;
kn->kn_fflags = 0;
knote_reset_priority(kq, kn, kev->qos);
/* Add the knote for lookup thru the fd table */
error = kq_add_knote(kq, kn, &knlc, p);
if (error) {
knote_free(kn);
if (knote_fp != NULL) {
fp_drop(p, (int)kev->ident, knote_fp, 0);
}
if (error == ERESTART) {
goto restart;
}
goto out;
}
/* fp reference count now applies to knote */
/*
* we can't use filter_call() because f_attach can change the filter ops
* for a filter that supports f_extended_codes, so we need to reload
* knote_fops() and not use `fops`.
*/
result = fops->f_attach(kn, kev);
if (result && !knote_fops(kn)->f_extended_codes) {
result = FILTER_ACTIVE;
}
kqlock(kq);
if (result & FILTER_THREADREQ_NODEFEER) {
enable_preemption();
}
if (kn->kn_flags & EV_ERROR) {
/*
* Failed to attach correctly, so drop.
*/
kn->kn_filtid = EVFILTID_DETACHED;
error = (int)kn->kn_sdata;
knote_drop(kq, kn, &knlc);
result = 0;
goto out;
}
/*
* end "attaching" phase - now just attached
*
* Mark the thread request overcommit, if appropos
*
* If the attach routine indicated that an
* event is already fired, activate the knote.
*/
if ((kn->kn_qos & _PTHREAD_PRIORITY_OVERCOMMIT_FLAG) &&
(kq->kq_state & KQ_WORKLOOP)) {
kqworkloop_set_overcommit((struct kqworkloop *)kq);
}
} else if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) {
/*
* The knote was dropped while we were waiting for the lock,
* we need to re-evaluate entirely
*/
goto restart;
} else if (kev->flags & EV_DELETE) {
/*
* Deletion of a knote (drop)
*
* If the filter wants to filter drop events, let it do so.
*
* defer-delete: when trying to delete a disabled EV_DISPATCH2 knote,
* we must wait for the knote to be re-enabled (unless it is being
* re-enabled atomically here).
*/
if (knote_fops(kn)->f_allow_drop) {
bool drop;
kqunlock(kq);
drop = knote_fops(kn)->f_allow_drop(kn, kev);
kqlock(kq);
if (!drop) {
goto out_unlock;
}
}
if ((kev->flags & EV_ENABLE) == 0 &&
(kn->kn_flags & EV_DISPATCH2) == EV_DISPATCH2 &&
(kn->kn_status & KN_DISABLED) != 0) {
kn->kn_status |= KN_DEFERDELETE;
error = EINPROGRESS;
goto out_unlock;
}
knote_drop(kq, kn, &knlc);
goto out;
} else {
/*
* Regular update of a knote (touch)
*
* Call touch routine to notify filter of changes in filter values
* (and to re-determine if any events are fired).
*
* If the knote is in defer-delete, avoid calling the filter touch
* routine (it has delivered its last event already).
*
* If the touch routine had no failure,
* apply the requested side effects to the knote.
*/
if (kn->kn_status & (KN_DEFERDELETE | KN_VANISHED)) {
if (kev->flags & EV_ENABLE) {
result = FILTER_ACTIVE;
}
} else {
kqunlock(kq);
result = filter_call(knote_fops(kn), f_touch(kn, kev));
kqlock(kq);
if (result & FILTER_THREADREQ_NODEFEER) {
enable_preemption();
}
}
if (kev->flags & EV_ERROR) {
result = 0;
goto out_unlock;
}
if ((kn->kn_flags & EV_UDATA_SPECIFIC) == 0 &&
kn->kn_udata != kev->udata) {
// this allows klist_copy_udata() not to take locks
os_atomic_store_wide(&kn->kn_udata, kev->udata, relaxed);
}
if ((kev->flags & EV_DISABLE) && !(kn->kn_status & KN_DISABLED)) {
kn->kn_status |= KN_DISABLED;
knote_dequeue(kq, kn);
}
}
/* accept new kevent state */
knote_apply_touch(kq, kn, kev, result);
out_unlock:
/*
* When the filter asked for a post-register wait,
* we leave the kqueue locked for kevent_register()
* to call the filter's f_post_register_wait hook.
*/
if (result & FILTER_REGISTER_WAIT) {
knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS);
*kn_out = kn;
} else {
knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK);
}
out:
/* output local errors through the kevent */
if (error) {
kev->flags |= EV_ERROR;
kev->data = error;
}
return result;
}
/*
* 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, we will have taken
* a copy of the state under the filter lock. We use that
* snapshot to dispatch the knote for future processing (or
* not, if this was a lost event).
*
* Our caller assures us that nobody else can be processing
* events from this knote during the whole operation. But
* others can be touching or posting events to the knote
* interspersed with our processing it.
*
* 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_ctx_t kectx,
kevent_callback_t callback)
{
struct kevent_qos_s kev;
struct kqueue *kq = knote_get_kq(kn);
KNOTE_LOCK_CTX(knlc);
int result = FILTER_ACTIVE;
int error = 0;
bool drop = false;
/*
* Must be active
* Must be queued and not disabled/suppressed or dropping
*/
assert(kn->kn_status & KN_QUEUED);
assert(kn->kn_status & KN_ACTIVE);
assert(!(kn->kn_status & (KN_DISABLED | KN_SUPPRESSED | KN_DROPPING)));
if (kq->kq_state & KQ_WORKLOOP) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS),
((struct kqworkloop *)kq)->kqwl_dynamicid,
kn->kn_udata, kn->kn_status | (kn->kn_id << 32),
kn->kn_filtid);
} else if (kq->kq_state & KQ_WORKQ) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS),
0, kn->kn_udata, kn->kn_status | (kn->kn_id << 32),
kn->kn_filtid);
} else {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS),
VM_KERNEL_UNSLIDE_OR_PERM(kq), kn->kn_udata,
kn->kn_status | (kn->kn_id << 32), kn->kn_filtid);
}
if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS)) {
/*
* When the knote is dropping or has dropped,
* then there's nothing we want to process.
*/
return EJUSTRETURN;
}
/*
* While waiting for the knote lock, we may have dropped the kq lock.
* and a touch may have disabled and dequeued the knote.
*/
if (!(kn->kn_status & KN_QUEUED)) {
knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS);
return EJUSTRETURN;
}
/*
* For deferred-drop or vanished events, we just create a fake
* event to acknowledge end-of-life. Otherwise, we call the
* filter's process routine to snapshot the kevent state under
* the filter's locking protocol.
*
* suppress knotes to avoid returning the same event multiple times in
* a single call.
*/
knote_suppress(kq, kn);
if (kn->kn_status & (KN_DEFERDELETE | KN_VANISHED)) {
uint16_t kev_flags = EV_DISPATCH2 | EV_ONESHOT;
if (kn->kn_status & KN_DEFERDELETE) {
kev_flags |= EV_DELETE;
} else {
kev_flags |= EV_VANISHED;
}
/* create fake event */
kev = (struct kevent_qos_s){
.filter = kn->kn_filter,
.ident = kn->kn_id,
.flags = kev_flags,
.udata = kn->kn_udata,
};
} else {
kqunlock(kq);
kev = (struct kevent_qos_s) { };
result = filter_call(knote_fops(kn), f_process(kn, &kev));
kqlock(kq);
}
/*
* Determine how to dispatch the knote for future event handling.
* not-fired: just return (do not callout, leave deactivated).
* One-shot: If dispatch2, enter deferred-delete mode (unless this is
* is the deferred delete event delivery itself). Otherwise,
* drop it.
* Dispatch: don't clear state, just mark it disabled.
* Cleared: just leave it deactivated.
* Others: re-activate as there may be more events to handle.
* This will not wake up more handlers right now, but
* at the completion of handling events it may trigger
* more handler threads (TODO: optimize based on more than
* just this one event being detected by the filter).
*/
if ((result & FILTER_ACTIVE) == 0) {
if ((kn->kn_status & KN_ACTIVE) == 0) {
/*
* Some knotes (like EVFILT_WORKLOOP) can be reactivated from
* within f_process() but that doesn't necessarily make them
* ready to process, so we should leave them be.
*
* For other knotes, since we will not return an event,
* there's no point keeping the knote suppressed.
*/
knote_unsuppress(kq, kn);
}
knote_unlock(kq, kn, &knlc, KNOTE_KQ_LOCK_ALWAYS);
return EJUSTRETURN;
}
if (result & FILTER_ADJUST_EVENT_QOS_BIT) {
knote_adjust_qos(kq, kn, result);
}
if (result & FILTER_ADJUST_EVENT_IOTIER_BIT) {
kqueue_update_iotier_override(kq);
}
kev.qos = _pthread_priority_combine(kn->kn_qos, kn->kn_qos_override);
if (kev.flags & EV_ONESHOT) {
if ((kn->kn_flags & EV_DISPATCH2) == EV_DISPATCH2 &&
(kn->kn_status & KN_DEFERDELETE) == 0) {
/* defer dropping non-delete oneshot dispatch2 events */
kn->kn_status |= KN_DEFERDELETE | KN_DISABLED;
} else {
drop = true;
}
} else if (kn->kn_flags & EV_DISPATCH) {
/* disable all dispatch knotes */
kn->kn_status |= KN_DISABLED;
} else if ((kn->kn_flags & EV_CLEAR) == 0) {
/* re-activate in case there are more events */
knote_activate(kq, kn, FILTER_ACTIVE);
}
/*
* callback to handle each event as we find it.
* If we have to detach and drop the knote, do
* it while we have the kq unlocked.
*/
if (drop) {
knote_drop(kq, kn, &knlc);
} else {
knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK);
}
if (kev.flags & EV_VANISHED) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KNOTE_VANISHED),
kev.ident, kn->kn_udata, kn->kn_status | (kn->kn_id << 32),
kn->kn_filtid);
}
error = (callback)(&kev, kectx);
kqlock(kq);
return error;
}
/*
* Returns -1 if the kqueue was unbound and processing should not happen
*/
#define KQWQAE_BEGIN_PROCESSING 1
#define KQWQAE_END_PROCESSING 2
#define KQWQAE_UNBIND 3
static int
kqworkq_acknowledge_events(struct kqworkq *kqwq, workq_threadreq_t kqr,
int kevent_flags, int kqwqae_op)
{
struct knote *kn;
int rc = 0;
bool unbind;
struct kqtailq *suppressq = &kqwq->kqwq_suppressed[kqr->tr_kq_qos_index - 1];
struct kqtailq *queue = &kqwq->kqwq_queue[kqr->tr_kq_qos_index - 1];
kqlock_held(&kqwq->kqwq_kqueue);
/*
* Return suppressed knotes to their original state.
* For workq kqueues, suppressed ones that are still
* truly active (not just forced into the queue) will
* set flags we check below to see if anything got
* woken up.
*/
while ((kn = TAILQ_FIRST(suppressq)) != NULL) {
knote_unsuppress(kqwq, kn);
}
if (kqwqae_op == KQWQAE_UNBIND) {
unbind = true;
} else if ((kevent_flags & KEVENT_FLAG_PARKING) == 0) {
unbind = false;
} else {
unbind = TAILQ_EMPTY(queue);
}
if (unbind) {
thread_t thread = kqr_thread_fast(kqr);
thread_qos_t old_override;
#if DEBUG || DEVELOPMENT
thread_t self = current_thread();
struct uthread *ut = get_bsdthread_info(self);
assert(thread == self);
assert(ut->uu_kqr_bound == kqr);
#endif // DEBUG || DEVELOPMENT
old_override = kqworkq_unbind_locked(kqwq, kqr, thread);
if (!TAILQ_EMPTY(queue)) {
/*
* Request a new thread if we didn't process the whole
* queue.
*/
kqueue_threadreq_initiate(&kqwq->kqwq_kqueue, kqr,
kqr->tr_kq_qos_index, 0);
}
if (old_override) {
thread_drop_kevent_override(thread);
}
rc = -1;
}
return rc;
}
/*
* Return 0 to indicate that processing should proceed,
* -1 if there is nothing to process.
*
* Called with kqueue locked and returns the same way,
* but may drop lock temporarily.
*/
static int
kqworkq_begin_processing(struct kqworkq *kqwq, workq_threadreq_t kqr,
int kevent_flags)
{
int rc = 0;
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS_BEGIN) | DBG_FUNC_START,
0, kqr->tr_kq_qos_index);
rc = kqworkq_acknowledge_events(kqwq, kqr, kevent_flags,
KQWQAE_BEGIN_PROCESSING);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_PROCESS_BEGIN) | DBG_FUNC_END,
thread_tid(kqr_thread(kqr)),
!TAILQ_EMPTY(&kqwq->kqwq_queue[kqr->tr_kq_qos_index - 1]));
return rc;
}
static thread_qos_t
kqworkloop_acknowledge_events(struct kqworkloop *kqwl)
{
kq_index_t qos = THREAD_QOS_UNSPECIFIED;
struct knote *kn, *tmp;
kqlock_held(kqwl);
TAILQ_FOREACH_SAFE(kn, &kqwl->kqwl_suppressed, kn_tqe, tmp) {
/*
* If a knote that can adjust QoS is disabled because of the automatic
* behavior of EV_DISPATCH, the knotes should stay suppressed so that
* further overrides keep pushing.
*/
if (knote_fops(kn)->f_adjusts_qos &&
(kn->kn_status & KN_DISABLED) != 0 &&
(kn->kn_status & KN_DROPPING) == 0 &&
(kn->kn_flags & (EV_DISPATCH | EV_DISABLE)) == EV_DISPATCH) {
qos = MAX(qos, kn->kn_qos_override);
continue;
}
knote_unsuppress(kqwl, kn);
}
return qos;
}
static int
kqworkloop_begin_processing(struct kqworkloop *kqwl, unsigned int kevent_flags)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
struct kqueue *kq = &kqwl->kqwl_kqueue;
int rc = 0, op = KQWL_UTQ_NONE;
kqlock_held(kq);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_BEGIN) | DBG_FUNC_START,
kqwl->kqwl_dynamicid, 0, 0);
/* nobody else should still be processing */
assert((kq->kq_state & KQ_PROCESSING) == 0);
kq->kq_state |= KQ_PROCESSING;
if (kevent_flags & KEVENT_FLAG_PARKING) {
/*
* When "parking" we want to process events and if no events are found
* unbind.
*
* However, non overcommit threads sometimes park even when they have
* more work so that the pool can narrow. For these, we need to unbind
* early, so that calling kqworkloop_update_threads_qos() can ask the
* workqueue subsystem whether the thread should park despite having
* pending events.
*/
if (kqr->tr_flags & WORKQ_TR_FLAG_OVERCOMMIT) {
op = KQWL_UTQ_PARKING;
} else {
op = KQWL_UTQ_UNBINDING;
}
} else if (!TAILQ_EMPTY(&kqwl->kqwl_suppressed)) {
op = KQWL_UTQ_RESET_WAKEUP_OVERRIDE;
}
if (op != KQWL_UTQ_NONE) {
thread_qos_t qos_override;
thread_t thread = kqr_thread_fast(kqr);
qos_override = kqworkloop_acknowledge_events(kqwl);
if (op == KQWL_UTQ_UNBINDING) {
kqworkloop_unbind_locked(kqwl, thread,
KQWL_OVERRIDE_DROP_IMMEDIATELY);
kqworkloop_release_live(kqwl);
}
kqworkloop_update_threads_qos(kqwl, op, qos_override);
if (op == KQWL_UTQ_PARKING &&
(!kqwl->kqwl_count || kqwl->kqwl_owner)) {
kqworkloop_unbind_locked(kqwl, thread,
KQWL_OVERRIDE_DROP_DELAYED);
kqworkloop_release_live(kqwl);
rc = -1;
} else if (op == KQWL_UTQ_UNBINDING &&
kqr_thread(kqr) != thread) {
rc = -1;
}
if (rc == -1) {
kq->kq_state &= ~KQ_PROCESSING;
kqworkloop_unbind_delayed_override_drop(thread);
}
}
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_BEGIN) | DBG_FUNC_END,
kqwl->kqwl_dynamicid, 0, 0);
return rc;
}
/*
* Return 0 to indicate that processing should proceed,
* -1 if there is nothing to process.
* EBADF if the kqueue is draining
*
* Called with kqueue locked and returns the same way,
* but may drop lock temporarily.
* May block.
*/
static int
kqfile_begin_processing(struct kqfile *kq)
{
kqlock_held(kq);
assert((kq->kqf_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_START,
VM_KERNEL_UNSLIDE_OR_PERM(kq), 0);
/* wait to become the exclusive processing thread */
while ((kq->kqf_state & (KQ_PROCESSING | KQ_DRAIN)) == KQ_PROCESSING) {
kq->kqf_state |= KQ_PROCWAIT;
lck_spin_sleep(&kq->kqf_lock, LCK_SLEEP_DEFAULT,
&kq->kqf_suppressed, THREAD_UNINT | THREAD_WAIT_NOREPORT);
}
if (kq->kqf_state & KQ_DRAIN) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END,
VM_KERNEL_UNSLIDE_OR_PERM(kq), 2);
return EBADF;
}
/* Nobody else processing */
/* anything left to process? */
if (kq->kqf_count == 0) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END,
VM_KERNEL_UNSLIDE_OR_PERM(kq), 1);
return -1;
}
/* convert to processing mode */
kq->kqf_state |= KQ_PROCESSING;
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_BEGIN) | DBG_FUNC_END,
VM_KERNEL_UNSLIDE_OR_PERM(kq), 0);
return 0;
}
/*
* Try to end the processing, only called when a workq thread is attempting to
* park (KEVENT_FLAG_PARKING is set).
*
* When returning -1, the kqworkq is setup again so that it is ready to be
* processed.
*/
static int
kqworkq_end_processing(struct kqworkq *kqwq, workq_threadreq_t kqr,
int kevent_flags)
{
if (kevent_flags & KEVENT_FLAG_PARKING) {
/*
* if acknowledge events "succeeds" it means there are events,
* which is a failure condition for end_processing.
*/
int rc = kqworkq_acknowledge_events(kqwq, kqr, kevent_flags,
KQWQAE_END_PROCESSING);
if (rc == 0) {
return -1;
}
}
return 0;
}
/*
* Try to end the processing, only called when a workq thread is attempting to
* park (KEVENT_FLAG_PARKING is set).
*
* When returning -1, the kqworkq is setup again so that it is ready to be
* processed (as if kqworkloop_begin_processing had just been called).
*
* If successful and KEVENT_FLAG_PARKING was set in the kevent_flags,
* the kqworkloop is unbound from its servicer as a side effect.
*/
static int
kqworkloop_end_processing(struct kqworkloop *kqwl, int flags, int kevent_flags)
{
struct kqueue *kq = &kqwl->kqwl_kqueue;
workq_threadreq_t kqr = &kqwl->kqwl_request;
int rc = 0;
kqlock_held(kq);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_END) | DBG_FUNC_START,
kqwl->kqwl_dynamicid, 0, 0);
if (kevent_flags & KEVENT_FLAG_PARKING) {
thread_t thread = kqr_thread_fast(kqr);
thread_qos_t qos_override;
/*
* When KEVENT_FLAG_PARKING is set, we need to attempt
* an unbind while still under the lock.
*
* So we do everything kqworkloop_unbind() would do, but because
* we're inside kqueue_process(), if the workloop actually
* received events while our locks were dropped, we have
* the opportunity to fail the end processing and loop again.
*
* This avoids going through the process-wide workqueue lock
* hence scales better.
*/
assert(flags & KQ_PROCESSING);
qos_override = kqworkloop_acknowledge_events(kqwl);
kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_PARKING, qos_override);
if (kqwl->kqwl_wakeup_qos && !kqwl->kqwl_owner) {
rc = -1;
} else {
kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_DELAYED);
kqworkloop_release_live(kqwl);
kq->kq_state &= ~flags;
kqworkloop_unbind_delayed_override_drop(thread);
}
} else {
kq->kq_state &= ~flags;
kq->kq_state |= KQ_R2K_ARMED;
kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_RECOMPUTE_WAKEUP_QOS, 0);
}
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_PROCESS_END) | DBG_FUNC_END,
kqwl->kqwl_dynamicid, 0, 0);
return rc;
}
/*
* Called with kqueue lock held.
*
* 0: no more events
* -1: has more events
* EBADF: kqueue is in draining mode
*/
static int
kqfile_end_processing(struct kqfile *kq)
{
struct knote *kn;
int procwait;
kqlock_held(kq);
assert((kq->kqf_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQ_PROCESS_END),
VM_KERNEL_UNSLIDE_OR_PERM(kq), 0);
/*
* Return suppressed knotes to their original state.
*/
while ((kn = TAILQ_FIRST(&kq->kqf_suppressed)) != NULL) {
knote_unsuppress(kq, kn);
}
procwait = (kq->kqf_state & KQ_PROCWAIT);
kq->kqf_state &= ~(KQ_PROCESSING | KQ_PROCWAIT);
if (procwait) {
/* first wake up any thread already waiting to process */
thread_wakeup(&kq->kqf_suppressed);
}
if (kq->kqf_state & KQ_DRAIN) {
return EBADF;
}
return kq->kqf_count != 0 ? -1 : 0;
}
static int
kqueue_workloop_ctl_internal(proc_t p, uintptr_t cmd, uint64_t __unused options,
struct kqueue_workloop_params *params, int *retval)
{
int error = 0;
struct kqworkloop *kqwl;
struct filedesc *fdp = &p->p_fd;
workq_threadreq_param_t trp = { };
#if CONFIG_PREADOPT_TG
struct thread_group *trp_permanent_preadopt_tg = NULL;
integer_t trp_preadopt_priority = 0;
integer_t trp_preadopt_policy = 0;
#endif /* CONFIG_PREADOPT_TG */
switch (cmd) {
case KQ_WORKLOOP_CREATE:
if (!params->kqwlp_flags) {
error = EINVAL;
break;
}
if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_PRI) &&
(params->kqwlp_sched_pri < 1 ||
params->kqwlp_sched_pri > 63 /* MAXPRI_USER */)) {
error = EINVAL;
break;
}
if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_POL) &&
invalid_policy(params->kqwlp_sched_pol)) {
error = EINVAL;
break;
}
if ((params->kqwlp_flags & KQ_WORKLOOP_CREATE_CPU_PERCENT) &&
(params->kqwlp_cpu_percent <= 0 ||
params->kqwlp_cpu_percent > 100 ||
params->kqwlp_cpu_refillms <= 0 ||
params->kqwlp_cpu_refillms > 0x00ffffff)) {
error = EINVAL;
break;
}
if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_WORK_INTERVAL) {
#if CONFIG_PREADOPT_TG
kern_return_t kr;
kr = kern_work_interval_get_policy_from_port(params->kqwl_wi_port,
&trp_preadopt_policy,
&trp_preadopt_priority,
&trp_permanent_preadopt_tg);
if (kr != KERN_SUCCESS) {
error = EINVAL;
break;
}
/* The work interval comes with scheduling policy. */
if (trp_preadopt_policy) {
trp.trp_flags |= TRP_POLICY;
trp.trp_pol = (uint8_t)trp_preadopt_policy;
trp.trp_flags |= TRP_PRIORITY;
trp.trp_pri = (uint8_t)trp_preadopt_priority;
}
/*
* We take +1 ref on a thread group backing this work interval
* via kern_work_interval_get_policy_from_port and pass it on to kqwl.
* If, for whatever reasons, kqworkloop_get_or_create fails, we
* get back this ref.
*/
#else
error = ENOTSUP;
break;
#endif /* CONFIG_PREADOPT_TG */
}
if (!(trp.trp_flags & (TRP_POLICY | TRP_PRIORITY))) {
/*
* We always prefer scheduling policy + priority that comes with
* a work interval. It it does not exist, we fallback to what the user
* has asked.
*/
if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_PRI) {
trp.trp_flags |= TRP_PRIORITY;
trp.trp_pri = (uint8_t)params->kqwlp_sched_pri;
}
if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_SCHED_POL) {
trp.trp_flags |= TRP_POLICY;
trp.trp_pol = (uint8_t)params->kqwlp_sched_pol;
}
if (params->kqwlp_flags & KQ_WORKLOOP_CREATE_CPU_PERCENT) {
trp.trp_flags |= TRP_CPUPERCENT;
trp.trp_cpupercent = (uint8_t)params->kqwlp_cpu_percent;
trp.trp_refillms = params->kqwlp_cpu_refillms;
}
}
error = kqworkloop_get_or_create(p, params->kqwlp_id, &trp,
#if CONFIG_PREADOPT_TG
trp_permanent_preadopt_tg,
#endif /* CONFIG_PREADOPT_TG */
KEVENT_FLAG_DYNAMIC_KQUEUE | KEVENT_FLAG_WORKLOOP |
KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST, &kqwl);
if (error) {
#if CONFIG_PREADOPT_TG
/* In case of success, kqwl consumes this +1 ref. */
if (trp_permanent_preadopt_tg) {
thread_group_release(trp_permanent_preadopt_tg);
}
#endif
break;
}
if (!fdt_flag_test(fdp, FD_WORKLOOP)) {
/* FD_WORKLOOP indicates we've ever created a workloop
* via this syscall but its only ever added to a process, never
* removed.
*/
proc_fdlock(p);
fdt_flag_set(fdp, FD_WORKLOOP);
proc_fdunlock(p);
}
break;
case KQ_WORKLOOP_DESTROY:
error = kqworkloop_get_or_create(p, params->kqwlp_id, NULL,
#if CONFIG_PREADOPT_TG
NULL,
#endif /* CONFIG_PREADOPT_TG */
KEVENT_FLAG_DYNAMIC_KQUEUE | KEVENT_FLAG_WORKLOOP |
KEVENT_FLAG_DYNAMIC_KQ_MUST_EXIST, &kqwl);
if (error) {
break;
}
kqlock(kqwl);
trp.trp_value = kqwl->kqwl_params;
if (trp.trp_flags && !(trp.trp_flags & TRP_RELEASED)) {
trp.trp_flags |= TRP_RELEASED;
kqwl->kqwl_params = trp.trp_value;
kqworkloop_release_live(kqwl);
} else {
error = EINVAL;
}
kqunlock(kqwl);
kqworkloop_release(kqwl);
break;
}
*retval = 0;
return error;
}
int
kqueue_workloop_ctl(proc_t p, struct kqueue_workloop_ctl_args *uap, int *retval)
{
struct kqueue_workloop_params params = {
.kqwlp_id = 0,
};
if (uap->sz < sizeof(params.kqwlp_version)) {
return EINVAL;
}
size_t copyin_sz = MIN(sizeof(params), uap->sz);
int rv = copyin(uap->addr, &params, copyin_sz);
if (rv) {
return rv;
}
if (params.kqwlp_version != (int)uap->sz) {
return EINVAL;
}
return kqueue_workloop_ctl_internal(p, uap->cmd, uap->options, &params,
retval);
}
static int
kqueue_select(struct fileproc *fp, int which, void *wql, __unused vfs_context_t ctx)
{
struct kqfile *kq = (struct kqfile *)fp_get_data(fp);
int retnum = 0;
assert((kq->kqf_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
if (which == FREAD) {
kqlock(kq);
if (kqfile_begin_processing(kq) == 0) {
retnum = kq->kqf_count;
kqfile_end_processing(kq);
} else if ((kq->kqf_state & KQ_DRAIN) == 0) {
selrecord(kq->kqf_p, &kq->kqf_sel, wql);
}
kqunlock(kq);
}
return retnum;
}
/*
* kqueue_close -
*/
static int
kqueue_close(struct fileglob *fg, __unused vfs_context_t ctx)
{
struct kqfile *kqf = fg_get_data(fg);
assert((kqf->kqf_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
kqlock(kqf);
selthreadclear(&kqf->kqf_sel);
kqunlock(kqf);
kqueue_dealloc(&kqf->kqf_kqueue);
fg_set_data(fg, NULL);
return 0;
}
/*
* Max depth of the nested kq path that can be created.
* Note that this has to be less than the size of kq_level
* to avoid wrapping around and mislabeling the level. We also
* want to be aggressive about this so that we don't overflow the
* kernel stack while posting kevents
*/
#define MAX_NESTED_KQ 10
/*
* The callers has taken a use-count reference on this kqueue and will donate it
* to the kqueue we are being added to. This keeps the kqueue from closing until
* that relationship is torn down.
*/
static int
kqueue_kqfilter(struct fileproc *fp, struct knote *kn,
__unused struct kevent_qos_s *kev)
{
struct kqfile *kqf = (struct kqfile *)fp_get_data(fp);
struct kqueue *kq = &kqf->kqf_kqueue;
struct kqueue *parentkq = knote_get_kq(kn);
assert((kqf->kqf_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
if (parentkq == kq || kn->kn_filter != EVFILT_READ) {
knote_set_error(kn, EINVAL);
return 0;
}
/*
* We have to avoid creating a cycle when nesting kqueues
* inside another. Rather than trying to walk the whole
* potential DAG of nested kqueues, we just use a simple
* ceiling protocol. When a kqueue is inserted into another,
* we check that the (future) parent is not already nested
* into another kqueue at a lower level than the potenial
* child (because it could indicate a cycle). If that test
* passes, we just mark the nesting levels accordingly.
*
* Only up to MAX_NESTED_KQ can be nested.
*
* Note: kqworkq and kqworkloop cannot be nested and have reused their
* kq_level field, so ignore these as parent.
*/
kqlock(parentkq);
if ((parentkq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0) {
if (parentkq->kq_level > 0 &&
parentkq->kq_level < kq->kq_level) {
kqunlock(parentkq);
knote_set_error(kn, EINVAL);
return 0;
}
/* set parent level appropriately */
uint16_t plevel = (parentkq->kq_level == 0)? 2: parentkq->kq_level;
if (plevel < kq->kq_level + 1) {
if (kq->kq_level + 1 > MAX_NESTED_KQ) {
kqunlock(parentkq);
knote_set_error(kn, EINVAL);
return 0;
}
plevel = kq->kq_level + 1;
}
parentkq->kq_level = plevel;
}
kqunlock(parentkq);
kn->kn_filtid = EVFILTID_KQREAD;
kqlock(kq);
KNOTE_ATTACH(&kqf->kqf_sel.si_note, kn);
/* indicate nesting in child, if needed */
if (kq->kq_level == 0) {
kq->kq_level = 1;
}
int count = kq->kq_count;
kqunlock(kq);
return count > 0;
}
__attribute__((noinline))
static void
kqfile_wakeup(struct kqfile *kqf, long hint, wait_result_t wr)
{
/* wakeup a thread waiting on this queue */
selwakeup(&kqf->kqf_sel);
/* wake up threads in kqueue_scan() */
if (kqf->kqf_state & KQ_SLEEP) {
kqf->kqf_state &= ~KQ_SLEEP;
thread_wakeup_with_result(&kqf->kqf_count, wr);
}
if (hint == NOTE_REVOKE) {
/* wakeup threads waiting their turn to process */
if (kqf->kqf_state & KQ_PROCWAIT) {
assert(kqf->kqf_state & KQ_PROCESSING);
kqf->kqf_state &= ~KQ_PROCWAIT;
thread_wakeup(&kqf->kqf_suppressed);
}
/* no need to KNOTE: knote_fdclose() takes care of it */
} else {
/* wakeup other kqueues/select sets we're inside */
KNOTE(&kqf->kqf_sel.si_note, hint);
}
}
/*
* kqueue_drain - called when kq is closed
*/
static int
kqueue_drain(struct fileproc *fp, __unused vfs_context_t ctx)
{
struct kqfile *kqf = (struct kqfile *)fp_get_data(fp);
assert((kqf->kqf_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
kqlock(kqf);
kqf->kqf_state |= KQ_DRAIN;
kqfile_wakeup(kqf, NOTE_REVOKE, THREAD_RESTART);
kqunlock(kqf);
return 0;
}
int
kqueue_stat(struct kqueue *kq, void *ub, int isstat64, proc_t p)
{
assert((kq->kq_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0);
kqlock(kq);
if (isstat64 != 0) {
struct stat64 *sb64 = (struct stat64 *)ub;
bzero((void *)sb64, sizeof(*sb64));
sb64->st_size = kq->kq_count;
if (kq->kq_state & KQ_KEV_QOS) {
sb64->st_blksize = sizeof(struct kevent_qos_s);
} else if (kq->kq_state & KQ_KEV64) {
sb64->st_blksize = sizeof(struct kevent64_s);
} else if (IS_64BIT_PROCESS(p)) {
sb64->st_blksize = sizeof(struct user64_kevent);
} else {
sb64->st_blksize = sizeof(struct user32_kevent);
}
sb64->st_mode = S_IFIFO;
} else {
struct stat *sb = (struct stat *)ub;
bzero((void *)sb, sizeof(*sb));
sb->st_size = kq->kq_count;
if (kq->kq_state & KQ_KEV_QOS) {
sb->st_blksize = sizeof(struct kevent_qos_s);
} else if (kq->kq_state & KQ_KEV64) {
sb->st_blksize = sizeof(struct kevent64_s);
} else if (IS_64BIT_PROCESS(p)) {
sb->st_blksize = sizeof(struct user64_kevent);
} else {
sb->st_blksize = sizeof(struct user32_kevent);
}
sb->st_mode = S_IFIFO;
}
kqunlock(kq);
return 0;
}
static inline bool
kqueue_threadreq_can_use_ast(struct kqueue *kq)
{
if (current_proc() == kq->kq_p) {
/*
* Setting an AST from a non BSD syscall is unsafe: mach_msg_trap() can
* do combined send/receive and in the case of self-IPC, the AST may bet
* set on a thread that will not return to userspace and needs the
* thread the AST would create to unblock itself.
*
* At this time, we really want to target:
*
* - kevent variants that can cause thread creations, and dispatch
* really only uses kevent_qos and kevent_id,
*
* - workq_kernreturn (directly about thread creations)
*
* - bsdthread_ctl which is used for qos changes and has direct impact
* on the creator thread scheduling decisions.
*/
switch (current_uthread()->syscall_code) {
case SYS_kevent_qos:
case SYS_kevent_id:
case SYS_workq_kernreturn:
case SYS_bsdthread_ctl:
return true;
}
}
return false;
}
/*
* Interact with the pthread kext to request a servicing there at a specific QoS
* level.
*
* - Caller holds the kqlock
*
* - May be called with the kqueue's wait queue set locked,
* so cannot do anything that could recurse on that.
*/
static void
kqueue_threadreq_initiate(kqueue_t kqu, workq_threadreq_t kqr,
kq_index_t qos, int flags)
{
assert(kqr_thread(kqr) == THREAD_NULL);
assert(!kqr_thread_requested(kqr));
struct turnstile *ts = TURNSTILE_NULL;
if (workq_is_exiting(kqu.kq->kq_p)) {
return;
}
kqlock_held(kqu);
if (kqu.kq->kq_state & KQ_WORKLOOP) {
struct kqworkloop *kqwl = kqu.kqwl;
assert(kqwl->kqwl_owner == THREAD_NULL);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THREQUEST),
kqwl->kqwl_dynamicid, 0, qos, kqwl->kqwl_wakeup_qos);
ts = kqwl->kqwl_turnstile;
/* Add a thread request reference on the kqueue. */
kqworkloop_retain(kqwl);
#if CONFIG_PREADOPT_TG
thread_group_qos_t kqwl_preadopt_tg = os_atomic_load(
&kqwl->kqwl_preadopt_tg, relaxed);
if (KQWL_HAS_PERMANENT_PREADOPTED_TG(kqwl_preadopt_tg)) {
/*
* This kqwl has been permanently configured with a thread group.
* See kqworkloops with scheduling parameters.
*/
flags |= WORKQ_THREADREQ_REEVALUATE_PREADOPT_TG;
} else {
/*
* This thread is the one which is ack-ing the thread group on the kqwl
* under the kqlock and will take action accordingly, pairs with the
* release barrier in kqueue_set_preadopted_thread_group
*/
uint16_t tg_acknowledged;
if (os_atomic_cmpxchgv(&kqwl->kqwl_preadopt_tg_needs_redrive,
KQWL_PREADOPT_TG_NEEDS_REDRIVE, KQWL_PREADOPT_TG_CLEAR_REDRIVE,
&tg_acknowledged, acquire)) {
flags |= WORKQ_THREADREQ_REEVALUATE_PREADOPT_TG;
}
}
#endif
} else {
assert(kqu.kq->kq_state & KQ_WORKQ);
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_THREQUEST), -1, 0, qos,
!TAILQ_EMPTY(&kqu.kqwq->kqwq_queue[kqr->tr_kq_qos_index - 1]));
}
/*
* New-style thread request supported.
* Provide the pthread kext a pointer to a workq_threadreq_s structure for
* its use until a corresponding kqueue_threadreq_bind callback.
*/
if (kqueue_threadreq_can_use_ast(kqu.kq)) {
flags |= WORKQ_THREADREQ_SET_AST_ON_FAILURE;
}
if (qos == KQWQ_QOS_MANAGER) {
qos = WORKQ_THREAD_QOS_MANAGER;
}
if (!workq_kern_threadreq_initiate(kqu.kq->kq_p, kqr, ts, qos, flags)) {
/*
* Process is shutting down or exec'ing.
* All the kqueues are going to be cleaned up
* soon. Forget we even asked for a thread -
* and make sure we don't ask for more.
*/
kqu.kq->kq_state &= ~KQ_R2K_ARMED;
kqueue_release_live(kqu);
}
}
/*
* kqueue_threadreq_bind_prepost - prepost the bind to kevent
*
* This is used when kqueue_threadreq_bind may cause a lock inversion.
*/
__attribute__((always_inline))
void
kqueue_threadreq_bind_prepost(struct proc *p __unused, workq_threadreq_t kqr,
struct uthread *ut)
{
ut->uu_kqr_bound = kqr;
kqr->tr_thread = get_machthread(ut);
kqr->tr_state = WORKQ_TR_STATE_BINDING;
}
/*
* kqueue_threadreq_bind_commit - commit a bind prepost
*
* The workq code has to commit any binding prepost before the thread has
* a chance to come back to userspace (and do kevent syscalls) or be aborted.
*/
void
kqueue_threadreq_bind_commit(struct proc *p, thread_t thread)
{
struct uthread *ut = get_bsdthread_info(thread);
workq_threadreq_t kqr = ut->uu_kqr_bound;
kqueue_t kqu = kqr_kqueue(p, kqr);
kqlock(kqu);
if (kqr->tr_state == WORKQ_TR_STATE_BINDING) {
kqueue_threadreq_bind(p, kqr, thread, 0);
}
kqunlock(kqu);
}
static void
kqueue_threadreq_modify(kqueue_t kqu, workq_threadreq_t kqr, kq_index_t qos,
workq_kern_threadreq_flags_t flags)
{
assert(kqr_thread_requested_pending(kqr));
kqlock_held(kqu);
if (kqueue_threadreq_can_use_ast(kqu.kq)) {
flags |= WORKQ_THREADREQ_SET_AST_ON_FAILURE;
}
#if CONFIG_PREADOPT_TG
if (kqu.kq->kq_state & KQ_WORKLOOP) {
struct kqworkloop *kqwl = kqu.kqwl;
thread_group_qos_t kqwl_preadopt_tg = os_atomic_load(
&kqwl->kqwl_preadopt_tg, relaxed);
if (KQWL_HAS_PERMANENT_PREADOPTED_TG(kqwl_preadopt_tg)) {
/*
* This kqwl has been permanently configured with a thread group.
* See kqworkloops with scheduling parameters.
*/
flags |= WORKQ_THREADREQ_REEVALUATE_PREADOPT_TG;
} else {
uint16_t tg_ack_status;
/*
* This thread is the one which is ack-ing the thread group on the kqwl
* under the kqlock and will take action accordingly, needs acquire
* barrier.
*/
if (os_atomic_cmpxchgv(&kqwl->kqwl_preadopt_tg_needs_redrive, KQWL_PREADOPT_TG_NEEDS_REDRIVE,
KQWL_PREADOPT_TG_CLEAR_REDRIVE, &tg_ack_status, acquire)) {
flags |= WORKQ_THREADREQ_REEVALUATE_PREADOPT_TG;
}
}
}
#endif
workq_kern_threadreq_modify(kqu.kq->kq_p, kqr, qos, flags);
}
/*
* kqueue_threadreq_bind - bind thread to processing kqrequest
*
* The provided thread will be responsible for delivering events
* associated with the given kqrequest. Bind it and get ready for
* the thread to eventually arrive.
*/
void
kqueue_threadreq_bind(struct proc *p, workq_threadreq_t kqr, thread_t thread,
unsigned int flags)
{
kqueue_t kqu = kqr_kqueue(p, kqr);
struct uthread *ut = get_bsdthread_info(thread);
kqlock_held(kqu);
assert(ut->uu_kqueue_override == 0);
if (kqr->tr_state == WORKQ_TR_STATE_BINDING) {
assert(ut->uu_kqr_bound == kqr);
assert(kqr->tr_thread == thread);
} else {
assert(kqr_thread_requested_pending(kqr));
assert(kqr->tr_thread == THREAD_NULL);
assert(ut->uu_kqr_bound == NULL);
ut->uu_kqr_bound = kqr;
kqr->tr_thread = thread;
}
kqr->tr_state = WORKQ_TR_STATE_BOUND;
if (kqu.kq->kq_state & KQ_WORKLOOP) {
struct turnstile *ts = kqu.kqwl->kqwl_turnstile;
if (__improbable(thread == kqu.kqwl->kqwl_owner)) {
/*
* <rdar://problem/38626999> shows that asserting here is not ok.
*
* This is not supposed to happen for correct use of the interface,
* but it is sadly possible for userspace (with the help of memory
* corruption, such as over-release of a dispatch queue) to make
* the creator thread the "owner" of a workloop.
*
* Once that happens, and that creator thread picks up the same
* workloop as a servicer, we trip this codepath. We need to fixup
* the state to forget about this thread being the owner, as the
* entire workloop state machine expects servicers to never be
* owners and everything would basically go downhill from here.
*/
kqu.kqwl->kqwl_owner = THREAD_NULL;
if (kqworkloop_override(kqu.kqwl)) {
thread_drop_kevent_override(thread);
}
}
if (ts && (flags & KQUEUE_THREADERQ_BIND_NO_INHERITOR_UPDATE) == 0) {
/*
* Past this point, the interlock is the kq req lock again,
* so we can fix the inheritor for good.
*/
filt_wlupdate_inheritor(kqu.kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE);
turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_HELD);
}
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_BIND), kqu.kqwl->kqwl_dynamicid,
thread_tid(thread), kqr->tr_kq_qos_index,
(kqr->tr_kq_override_index << 16) | kqwl->kqwl_wakeup_qos);
ut->uu_kqueue_override = kqr->tr_kq_override_index;
if (kqr->tr_kq_override_index) {
thread_add_servicer_override(thread, kqr->tr_kq_override_index);
}
#if CONFIG_PREADOPT_TG
/* Remove reference from kqwl and mark it as bound with the SENTINEL */
thread_group_qos_t old_tg;
thread_group_qos_t new_tg;
int ret = os_atomic_rmw_loop(kqr_preadopt_thread_group_addr(kqr), old_tg, new_tg, relaxed, {
if ((old_tg == KQWL_PREADOPTED_TG_NEVER) || KQWL_HAS_PERMANENT_PREADOPTED_TG(old_tg)) {
/*
* Either an app or a kqwl permanently configured with a thread group.
* Nothing to do.
*/
os_atomic_rmw_loop_give_up(break);
}
assert(old_tg != KQWL_PREADOPTED_TG_PROCESSED);
new_tg = KQWL_PREADOPTED_TG_SENTINEL;
});
if (ret) {
KQWL_PREADOPT_TG_HISTORY_WRITE_ENTRY(kqu.kqwl, KQWL_PREADOPT_OP_SERVICER_BIND, old_tg, new_tg);
if (KQWL_HAS_VALID_PREADOPTED_TG(old_tg)) {
struct thread_group *tg = KQWL_GET_PREADOPTED_TG(old_tg);
assert(tg != NULL);
thread_set_preadopt_thread_group(thread, tg);
thread_group_release_live(tg); // The thread has a reference
} else {
/*
* The thread may already have a preadopt thread group on it -
* we need to make sure to clear that.
*/
thread_set_preadopt_thread_group(thread, NULL);
}
/* We have taken action on the preadopted thread group set on the
* set on the kqwl, clear any redrive requests */
os_atomic_store(&kqu.kqwl->kqwl_preadopt_tg_needs_redrive, KQWL_PREADOPT_TG_CLEAR_REDRIVE, relaxed);
} else {
if (KQWL_HAS_PERMANENT_PREADOPTED_TG(old_tg)) {
struct thread_group *tg = KQWL_GET_PREADOPTED_TG(old_tg);
assert(tg != NULL);
thread_set_preadopt_thread_group(thread, tg);
/*
* From this point on, kqwl and thread both have +1 ref on this tg.
*/
}
}
#endif
kqueue_update_iotier_override(kqu);
} else {
assert(kqr->tr_kq_override_index == 0);
#if CONFIG_PREADOPT_TG
/*
* The thread may have a preadopt thread group on it already because it
* got tagged with it as a creator thread. So we need to make sure to
* clear that since we don't have preadopt thread groups for non-kqwl
* cases
*/
thread_set_preadopt_thread_group(thread, NULL);
#endif
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_BIND), -1,
thread_tid(thread), kqr->tr_kq_qos_index,
(kqr->tr_kq_override_index << 16) |
!TAILQ_EMPTY(&kqu.kqwq->kqwq_queue[kqr->tr_kq_qos_index - 1]));
}
}
/*
* kqueue_threadreq_cancel - abort a pending thread request
*
* Called when exiting/exec'ing. Forget our pending request.
*/
void
kqueue_threadreq_cancel(struct proc *p, workq_threadreq_t kqr)
{
kqueue_release(kqr_kqueue(p, kqr));
}
workq_threadreq_param_t
kqueue_threadreq_workloop_param(workq_threadreq_t kqr)
{
struct kqworkloop *kqwl;
workq_threadreq_param_t trp;
assert(kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP);
kqwl = __container_of(kqr, struct kqworkloop, kqwl_request);
trp.trp_value = kqwl->kqwl_params;
return trp;
}
/*
* kqueue_threadreq_unbind - unbind thread from processing kqueue
*
* End processing the per-QoS bucket of events and allow other threads
* to be requested for future servicing.
*
* caller holds a reference on the kqueue.
*/
void
kqueue_threadreq_unbind(struct proc *p, workq_threadreq_t kqr)
{
if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) {
kqworkloop_unbind(kqr_kqworkloop(kqr));
} else {
kqworkq_unbind(p, kqr);
}
}
/*
* If we aren't already busy processing events [for this QoS],
* request workq thread support as appropriate.
*
* TBD - for now, we don't segregate out processing by QoS.
*
* - May be called with the kqueue's wait queue set locked,
* so cannot do anything that could recurse on that.
*/
static void
kqworkq_wakeup(struct kqworkq *kqwq, kq_index_t qos_index)
{
workq_threadreq_t kqr = kqworkq_get_request(kqwq, qos_index);
/* convert to thread qos value */
assert(qos_index > 0 && qos_index <= KQWQ_NBUCKETS);
if (!kqr_thread_requested(kqr)) {
kqueue_threadreq_initiate(&kqwq->kqwq_kqueue, kqr, qos_index, 0);
}
}
/*
* This represent the asynchronous QoS a given workloop contributes,
* hence is the max of the current active knotes (override index)
* and the workloop max qos (userspace async qos).
*/
static kq_index_t
kqworkloop_override(struct kqworkloop *kqwl)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
return MAX(kqr->tr_kq_qos_index, kqr->tr_kq_override_index);
}
static inline void
kqworkloop_request_fire_r2k_notification(struct kqworkloop *kqwl)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
kqlock_held(kqwl);
if (kqwl->kqwl_state & KQ_R2K_ARMED) {
kqwl->kqwl_state &= ~KQ_R2K_ARMED;
act_set_astkevent(kqr_thread_fast(kqr), AST_KEVENT_RETURN_TO_KERNEL);
}
}
static void
kqworkloop_update_threads_qos(struct kqworkloop *kqwl, int op, kq_index_t qos)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
struct kqueue *kq = &kqwl->kqwl_kqueue;
kq_index_t old_override = kqworkloop_override(kqwl);
kqlock_held(kqwl);
switch (op) {
case KQWL_UTQ_UPDATE_WAKEUP_QOS:
kqwl->kqwl_wakeup_qos = qos;
kqworkloop_request_fire_r2k_notification(kqwl);
goto recompute;
case KQWL_UTQ_RESET_WAKEUP_OVERRIDE:
kqr->tr_kq_override_index = qos;
goto recompute;
case KQWL_UTQ_PARKING:
case KQWL_UTQ_UNBINDING:
kqr->tr_kq_override_index = qos;
OS_FALLTHROUGH;
case KQWL_UTQ_RECOMPUTE_WAKEUP_QOS:
if (op == KQWL_UTQ_RECOMPUTE_WAKEUP_QOS) {
assert(qos == THREAD_QOS_UNSPECIFIED);
}
if (TAILQ_EMPTY(&kqwl->kqwl_suppressed)) {
kqr->tr_kq_override_index = THREAD_QOS_UNSPECIFIED;
}
kqwl->kqwl_wakeup_qos = 0;
for (kq_index_t i = KQWL_NBUCKETS; i > 0; i--) {
if (!TAILQ_EMPTY(&kqwl->kqwl_queue[i - 1])) {
kqwl->kqwl_wakeup_qos = i;
kqworkloop_request_fire_r2k_notification(kqwl);
break;
}
}
OS_FALLTHROUGH;
case KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE:
recompute:
/*
* When modifying the wakeup QoS or the override QoS, we always need to
* maintain our invariant that kqr_override_index is at least as large
* as the highest QoS for which an event is fired.
*
* However this override index can be larger when there is an overriden
* suppressed knote pushing on the kqueue.
*/
if (qos < kqwl->kqwl_wakeup_qos) {
qos = kqwl->kqwl_wakeup_qos;
}
if (kqr->tr_kq_override_index < qos) {
kqr->tr_kq_override_index = qos;
}
break;
case KQWL_UTQ_REDRIVE_EVENTS:
break;
case KQWL_UTQ_SET_QOS_INDEX:
kqr->tr_kq_qos_index = qos;
break;
default:
panic("unknown kqwl thread qos update operation: %d", op);
}
thread_t kqwl_owner = kqwl->kqwl_owner;
thread_t servicer = kqr_thread(kqr);
boolean_t qos_changed = FALSE;
kq_index_t new_override = kqworkloop_override(kqwl);
/*
* Apply the diffs to the owner if applicable
*/
if (kqwl_owner) {
#if 0
/* JMM - need new trace hooks for owner overrides */
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THADJUST),
kqwl->kqwl_dynamicid, thread_tid(kqwl_owner), kqr->tr_kq_qos_index,
(kqr->tr_kq_override_index << 16) | kqwl->kqwl_wakeup_qos);
#endif
if (new_override == old_override) {
// nothing to do
} else if (old_override == THREAD_QOS_UNSPECIFIED) {
thread_add_kevent_override(kqwl_owner, new_override);
} else if (new_override == THREAD_QOS_UNSPECIFIED) {
thread_drop_kevent_override(kqwl_owner);
} else { /* old_override != new_override */
thread_update_kevent_override(kqwl_owner, new_override);
}
}
/*
* apply the diffs to the servicer
*/
if (!kqr_thread_requested(kqr)) {
/*
* No servicer, nor thread-request
*
* Make a new thread request, unless there is an owner (or the workloop
* is suspended in userland) or if there is no asynchronous work in the
* first place.
*/
if (kqwl_owner == NULL && kqwl->kqwl_wakeup_qos) {
int initiate_flags = 0;
if (op == KQWL_UTQ_UNBINDING) {
initiate_flags = WORKQ_THREADREQ_ATTEMPT_REBIND;
}
/* kqueue_threadreq_initiate handles the acknowledgement of the TG
* if needed */
kqueue_threadreq_initiate(kq, kqr, new_override, initiate_flags);
}
} else if (servicer) {
/*
* Servicer in flight
*
* Just apply the diff to the servicer
*/
#if CONFIG_PREADOPT_TG
/* When there's a servicer for the kqwl already, then the servicer will
* adopt the thread group in the kqr, we don't need to poke the
* workqueue subsystem to make different decisions due to the thread
* group. Consider the current request ack-ed.
*/
os_atomic_store(&kqwl->kqwl_preadopt_tg_needs_redrive, KQWL_PREADOPT_TG_CLEAR_REDRIVE, relaxed);
#endif
struct uthread *ut = get_bsdthread_info(servicer);
if (ut->uu_kqueue_override != new_override) {
if (ut->uu_kqueue_override == THREAD_QOS_UNSPECIFIED) {
thread_add_servicer_override(servicer, new_override);
} else if (new_override == THREAD_QOS_UNSPECIFIED) {
thread_drop_servicer_override(servicer);
} else { /* ut->uu_kqueue_override != new_override */
thread_update_servicer_override(servicer, new_override);
}
ut->uu_kqueue_override = new_override;
qos_changed = TRUE;
}
} else if (new_override == THREAD_QOS_UNSPECIFIED) {
/*
* No events to deliver anymore.
*
* However canceling with turnstiles is challenging, so the fact that
* the request isn't useful will be discovered by the servicer himself
* later on.
*/
} else if (old_override != new_override) {
/*
* Request is in flight
*
* Apply the diff to the thread request.
*/
kqueue_threadreq_modify(kq, kqr, new_override, WORKQ_THREADREQ_NONE);
qos_changed = TRUE;
}
if (qos_changed) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_THADJUST), kqwl->kqwl_dynamicid,
thread_tid(servicer), kqr->tr_kq_qos_index,
(kqr->tr_kq_override_index << 16) | kqwl->kqwl_wakeup_qos);
}
}
static void
kqworkloop_update_iotier_override(struct kqworkloop *kqwl)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
thread_t servicer = kqr_thread(kqr);
uint8_t iotier = os_atomic_load(&kqwl->kqwl_iotier_override, relaxed);
kqlock_held(kqwl);
if (servicer) {
thread_update_servicer_iotier_override(servicer, iotier);
}
}
static void
kqworkloop_wakeup(struct kqworkloop *kqwl, kq_index_t qos)
{
if (qos <= kqwl->kqwl_wakeup_qos) {
/*
* Shortcut wakeups that really do nothing useful
*/
return;
}
if ((kqwl->kqwl_state & KQ_PROCESSING) &&
kqr_thread(&kqwl->kqwl_request) == current_thread()) {
/*
* kqworkloop_end_processing() will perform the required QoS
* computations when it unsets the processing mode.
*/
return;
}
kqworkloop_update_threads_qos(kqwl, KQWL_UTQ_UPDATE_WAKEUP_QOS, qos);
}
static struct kqtailq *
kqueue_get_suppressed_queue(kqueue_t kq, struct knote *kn)
{
if (kq.kq->kq_state & KQ_WORKLOOP) {
return &kq.kqwl->kqwl_suppressed;
} else if (kq.kq->kq_state & KQ_WORKQ) {
return &kq.kqwq->kqwq_suppressed[kn->kn_qos_index - 1];
} else {
return &kq.kqf->kqf_suppressed;
}
}
struct turnstile *
kqueue_alloc_turnstile(kqueue_t kqu)
{
struct kqworkloop *kqwl = kqu.kqwl;
kq_state_t kq_state;
kq_state = os_atomic_load(&kqu.kq->kq_state, dependency);
if (kq_state & KQ_HAS_TURNSTILE) {
/* force a dependency to pair with the atomic or with release below */
return os_atomic_load_with_dependency_on(&kqwl->kqwl_turnstile,
(uintptr_t)kq_state);
}
if (!(kq_state & KQ_WORKLOOP)) {
return TURNSTILE_NULL;
}
struct turnstile *ts = turnstile_alloc(), *free_ts = TURNSTILE_NULL;
bool workq_locked = false;
kqlock(kqu);
if (filt_wlturnstile_interlock_is_workq(kqwl)) {
workq_locked = true;
workq_kern_threadreq_lock(kqwl->kqwl_p);
}
if (kqwl->kqwl_state & KQ_HAS_TURNSTILE) {
free_ts = ts;
ts = kqwl->kqwl_turnstile;
} else {
ts = turnstile_prepare((uintptr_t)kqwl, &kqwl->kqwl_turnstile,
ts, TURNSTILE_WORKLOOPS);
/* release-barrier to pair with the unlocked load of kqwl_turnstile above */
os_atomic_or(&kqwl->kqwl_state, KQ_HAS_TURNSTILE, release);
if (filt_wlturnstile_interlock_is_workq(kqwl)) {
workq_kern_threadreq_update_inheritor(kqwl->kqwl_p,
&kqwl->kqwl_request, kqwl->kqwl_owner,
ts, TURNSTILE_IMMEDIATE_UPDATE);
/*
* The workq may no longer be the interlock after this.
* In which case the inheritor wasn't updated.
*/
}
if (!filt_wlturnstile_interlock_is_workq(kqwl)) {
filt_wlupdate_inheritor(kqwl, ts, TURNSTILE_IMMEDIATE_UPDATE);
}
}
if (workq_locked) {
workq_kern_threadreq_unlock(kqwl->kqwl_p);
}
kqunlock(kqu);
if (free_ts) {
turnstile_deallocate(free_ts);
} else {
turnstile_update_inheritor_complete(ts, TURNSTILE_INTERLOCK_NOT_HELD);
}
return ts;
}
__attribute__((always_inline))
struct turnstile *
kqueue_turnstile(kqueue_t kqu)
{
kq_state_t kq_state = os_atomic_load(&kqu.kq->kq_state, relaxed);
if (kq_state & KQ_WORKLOOP) {
return os_atomic_load(&kqu.kqwl->kqwl_turnstile, relaxed);
}
return TURNSTILE_NULL;
}
__attribute__((always_inline))
struct turnstile *
kqueue_threadreq_get_turnstile(workq_threadreq_t kqr)
{
struct kqworkloop *kqwl = kqr_kqworkloop(kqr);
if (kqwl) {
return os_atomic_load(&kqwl->kqwl_turnstile, relaxed);
}
return TURNSTILE_NULL;
}
static void
kqworkloop_set_overcommit(struct kqworkloop *kqwl)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
/*
* This test is racy, but since we never remove this bit,
* it allows us to avoid taking a lock.
*/
if (kqr->tr_flags & WORKQ_TR_FLAG_OVERCOMMIT) {
return;
}
kqlock_held(kqwl);
if (kqr_thread_requested_pending(kqr)) {
kqueue_threadreq_modify(kqwl, kqr, kqr->tr_qos,
WORKQ_THREADREQ_MAKE_OVERCOMMIT);
} else {
kqr->tr_flags |= WORKQ_TR_FLAG_OVERCOMMIT;
}
}
static void
kqworkq_update_override(struct kqworkq *kqwq, struct knote *kn,
kq_index_t override_index)
{
workq_threadreq_t kqr;
kq_index_t old_override_index;
kq_index_t queue_index = kn->kn_qos_index;
if (override_index <= queue_index) {
return;
}
kqr = kqworkq_get_request(kqwq, queue_index);
kqlock_held(kqwq);
old_override_index = kqr->tr_kq_override_index;
if (override_index > MAX(kqr->tr_kq_qos_index, old_override_index)) {
thread_t servicer = kqr_thread(kqr);
kqr->tr_kq_override_index = override_index;
/* apply the override to [incoming?] servicing thread */
if (servicer) {
if (old_override_index) {
thread_update_kevent_override(servicer, override_index);
} else {
thread_add_kevent_override(servicer, override_index);
}
}
}
}
static void
kqueue_update_iotier_override(kqueue_t kqu)
{
if (kqu.kq->kq_state & KQ_WORKLOOP) {
kqworkloop_update_iotier_override(kqu.kqwl);
}
}
static void
kqueue_update_override(kqueue_t kqu, struct knote *kn, thread_qos_t qos)
{
if (kqu.kq->kq_state & KQ_WORKLOOP) {
kqworkloop_update_threads_qos(kqu.kqwl, KQWL_UTQ_UPDATE_WAKEUP_OVERRIDE,
qos);
} else {
kqworkq_update_override(kqu.kqwq, kn, qos);
}
}
static void
kqworkloop_unbind_locked(struct kqworkloop *kqwl, thread_t thread,
enum kqwl_unbind_locked_mode how)
{
struct uthread *ut = get_bsdthread_info(thread);
workq_threadreq_t kqr = &kqwl->kqwl_request;
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWL_UNBIND), kqwl->kqwl_dynamicid,
thread_tid(thread), 0, 0);
kqlock_held(kqwl);
assert(ut->uu_kqr_bound == kqr);
ut->uu_kqr_bound = NULL;
if (how == KQWL_OVERRIDE_DROP_IMMEDIATELY &&
ut->uu_kqueue_override != THREAD_QOS_UNSPECIFIED) {
thread_drop_servicer_override(thread);
ut->uu_kqueue_override = THREAD_QOS_UNSPECIFIED;
}
if (kqwl->kqwl_owner == NULL && kqwl->kqwl_turnstile) {
turnstile_update_inheritor(kqwl->kqwl_turnstile,
TURNSTILE_INHERITOR_NULL, TURNSTILE_IMMEDIATE_UPDATE);
turnstile_update_inheritor_complete(kqwl->kqwl_turnstile,
TURNSTILE_INTERLOCK_HELD);
}
#if CONFIG_PREADOPT_TG
/* The kqueue is able to adopt a thread group again */
thread_group_qos_t old_tg, new_tg = NULL;
int ret = os_atomic_rmw_loop(kqr_preadopt_thread_group_addr(kqr), old_tg, new_tg, relaxed, {
new_tg = old_tg;
if (old_tg == KQWL_PREADOPTED_TG_SENTINEL || old_tg == KQWL_PREADOPTED_TG_PROCESSED) {
new_tg = KQWL_PREADOPTED_TG_NULL;
}
});
if (ret) {
KQWL_PREADOPT_TG_HISTORY_WRITE_ENTRY(kqwl, KQWL_PREADOPT_OP_SERVICER_UNBIND, old_tg, KQWL_PREADOPTED_TG_NULL);
// Servicer can drop any preadopt thread group it has since it has
// unbound.
thread_set_preadopt_thread_group(thread, NULL);
}
#endif
thread_update_servicer_iotier_override(thread, THROTTLE_LEVEL_END);
kqr->tr_thread = THREAD_NULL;
kqr->tr_state = WORKQ_TR_STATE_IDLE;
kqwl->kqwl_state &= ~KQ_R2K_ARMED;
}
static void
kqworkloop_unbind_delayed_override_drop(thread_t thread)
{
struct uthread *ut = get_bsdthread_info(thread);
assert(ut->uu_kqr_bound == NULL);
if (ut->uu_kqueue_override != THREAD_QOS_UNSPECIFIED) {
thread_drop_servicer_override(thread);
ut->uu_kqueue_override = THREAD_QOS_UNSPECIFIED;
}
}
/*
* kqworkloop_unbind - Unbind the servicer thread of a workloop kqueue
*
* It will acknowledge events, and possibly request a new thread if:
* - there were active events left
* - we pended waitq hook callouts during processing
* - we pended wakeups while processing (or unsuppressing)
*
* Called with kqueue lock held.
*/
static void
kqworkloop_unbind(struct kqworkloop *kqwl)
{
struct kqueue *kq = &kqwl->kqwl_kqueue;
workq_threadreq_t kqr = &kqwl->kqwl_request;
thread_t thread = kqr_thread_fast(kqr);
int op = KQWL_UTQ_PARKING;
kq_index_t qos_override = THREAD_QOS_UNSPECIFIED;
assert(thread == current_thread());
kqlock(kqwl);
/*
* Forcing the KQ_PROCESSING flag allows for QoS updates because of
* unsuppressing knotes not to be applied until the eventual call to
* kqworkloop_update_threads_qos() below.
*/
assert((kq->kq_state & KQ_PROCESSING) == 0);
if (!TAILQ_EMPTY(&kqwl->kqwl_suppressed)) {
kq->kq_state |= KQ_PROCESSING;
qos_override = kqworkloop_acknowledge_events(kqwl);
kq->kq_state &= ~KQ_PROCESSING;
}
kqworkloop_unbind_locked(kqwl, thread, KQWL_OVERRIDE_DROP_DELAYED);
kqworkloop_update_threads_qos(kqwl, op, qos_override);
kqunlock(kqwl);
/*
* Drop the override on the current thread last, after the call to
* kqworkloop_update_threads_qos above.
*/
kqworkloop_unbind_delayed_override_drop(thread);
/* If last reference, dealloc the workloop kq */
kqworkloop_release(kqwl);
}
static thread_qos_t
kqworkq_unbind_locked(struct kqworkq *kqwq,
workq_threadreq_t kqr, thread_t thread)
{
struct uthread *ut = get_bsdthread_info(thread);
kq_index_t old_override = kqr->tr_kq_override_index;
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KQWQ_UNBIND), -1,
thread_tid(kqr_thread(kqr)), kqr->tr_kq_qos_index, 0);
kqlock_held(kqwq);
assert(ut->uu_kqr_bound == kqr);
ut->uu_kqr_bound = NULL;
kqr->tr_thread = THREAD_NULL;
kqr->tr_state = WORKQ_TR_STATE_IDLE;
kqr->tr_kq_override_index = THREAD_QOS_UNSPECIFIED;
kqwq->kqwq_state &= ~KQ_R2K_ARMED;
return old_override;
}
/*
* kqworkq_unbind - unbind of a workq kqueue from a thread
*
* We may have to request new threads.
* This can happen there are no waiting processing threads and:
* - there were active events we never got to (count > 0)
* - we pended waitq hook callouts during processing
* - we pended wakeups while processing (or unsuppressing)
*/
static void
kqworkq_unbind(proc_t p, workq_threadreq_t kqr)
{
struct kqworkq *kqwq = (struct kqworkq *)p->p_fd.fd_wqkqueue;
__assert_only int rc;
kqlock(kqwq);
rc = kqworkq_acknowledge_events(kqwq, kqr, 0, KQWQAE_UNBIND);
assert(rc == -1);
kqunlock(kqwq);
}
workq_threadreq_t
kqworkq_get_request(struct kqworkq *kqwq, kq_index_t qos_index)
{
assert(qos_index > 0 && qos_index <= KQWQ_NBUCKETS);
return &kqwq->kqwq_request[qos_index - 1];
}
static void
knote_reset_priority(kqueue_t kqu, struct knote *kn, pthread_priority_t pp)
{
kq_index_t qos = _pthread_priority_thread_qos(pp);
if (kqu.kq->kq_state & KQ_WORKLOOP) {
assert((pp & _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG) == 0);
pp = _pthread_priority_normalize(pp);
} else if (kqu.kq->kq_state & KQ_WORKQ) {
if (qos == THREAD_QOS_UNSPECIFIED) {
/* On workqueues, outside of QoS means MANAGER */
qos = KQWQ_QOS_MANAGER;
pp = _PTHREAD_PRIORITY_EVENT_MANAGER_FLAG;
} else {
pp = _pthread_priority_normalize(pp);
}
} else {
pp = _pthread_unspecified_priority();
qos = THREAD_QOS_UNSPECIFIED;
}
kn->kn_qos = (int32_t)pp;
if ((kn->kn_status & KN_MERGE_QOS) == 0 || qos > kn->kn_qos_override) {
/* Never lower QoS when in "Merge" mode */
kn->kn_qos_override = qos;
}
/* only adjust in-use qos index when not suppressed */
if (kn->kn_status & KN_SUPPRESSED) {
kqueue_update_override(kqu, kn, qos);
} else if (kn->kn_qos_index != qos) {
knote_dequeue(kqu, kn);
kn->kn_qos_index = qos;
}
}
static void
knote_adjust_qos(struct kqueue *kq, struct knote *kn, int result)
{
thread_qos_t qos_index = (result >> FILTER_ADJUST_EVENT_QOS_SHIFT) & 7;
kqlock_held(kq);
assert(result & FILTER_ADJUST_EVENT_QOS_BIT);
assert(qos_index < THREAD_QOS_LAST);
/*
* Early exit for knotes that should not change QoS
*/
if (__improbable(!knote_fops(kn)->f_adjusts_qos)) {
panic("filter %d cannot change QoS", kn->kn_filtid);
} else if (__improbable(!knote_has_qos(kn))) {
return;
}
/*
* knotes with the FALLBACK flag will only use their registration QoS if the
* incoming event has no QoS, else, the registration QoS acts as a floor.
*/
thread_qos_t req_qos = _pthread_priority_thread_qos_fast(kn->kn_qos);
if (kn->kn_qos & _PTHREAD_PRIORITY_FALLBACK_FLAG) {
if (qos_index == THREAD_QOS_UNSPECIFIED) {
qos_index = req_qos;
}
} else {
if (qos_index < req_qos) {
qos_index = req_qos;
}
}
if ((kn->kn_status & KN_MERGE_QOS) && (qos_index < kn->kn_qos_override)) {
/* Never lower QoS when in "Merge" mode */
return;
}
if ((kn->kn_status & KN_LOCKED) && (kn->kn_status & KN_POSTING)) {
/*
* When we're trying to update the QoS override and that both an
* f_event() and other f_* calls are running concurrently, any of these
* in flight calls may want to perform overrides that aren't properly
* serialized with each other.
*
* The first update that observes this racy situation enters a "Merge"
* mode which causes subsequent override requests to saturate the
* override instead of replacing its value.
*
* This mode is left when knote_unlock() or knote_post()
* observe that no other f_* routine is in flight.
*/
kn->kn_status |= KN_MERGE_QOS;
}
/*
* Now apply the override if it changed.
*/
if (kn->kn_qos_override == qos_index) {
return;
}
kn->kn_qos_override = qos_index;
if (kn->kn_status & KN_SUPPRESSED) {
/*
* For suppressed events, the kn_qos_index field cannot be touched as it
* allows us to know on which supress queue the knote is for a kqworkq.
*
* Also, there's no natural push applied on the kqueues when this field
* changes anyway. We hence need to apply manual overrides in this case,
* which will be cleared when the events are later acknowledged.
*/
kqueue_update_override(kq, kn, qos_index);
} else if (kn->kn_qos_index != qos_index) {
knote_dequeue(kq, kn);
kn->kn_qos_index = qos_index;
}
}
void
klist_init(struct klist *list)
{
SLIST_INIT(list);
}
/*
* Query/Post each knote in the object's list
*
* The object lock protects the list. It is assumed that the filter/event
* routine for the object can determine that the object is already locked (via
* the hint) and not deadlock itself.
*
* Autodetach is a specific contract which will detach all knotes from the
* object prior to posting the final event for that knote. This is done while
* under the object lock. A breadcrumb is left in the knote's next pointer to
* indicate to future calls to f_detach routines that they need not reattempt
* to knote_detach from the object's klist again. This is currently used by
* EVFILTID_SPEC, EVFILTID_TTY, EVFILTID_PTMX
*
*/
void
knote(struct klist *list, long hint, bool autodetach)
{
struct knote *kn;
struct knote *tmp_kn;
SLIST_FOREACH_SAFE(kn, list, kn_selnext, tmp_kn) {
/*
* We can modify the knote's next pointer since since we are holding the
* object lock and the list can't be concurrently modified. Anyone
* determining auto-detached-ness of a knote should take the primitive lock
* to synchronize.
*
* Note that we do this here instead of the filter's f_event since we may
* not even post the event if the knote is being dropped.
*/
if (autodetach) {
kn->kn_selnext.sle_next = KNOTE_AUTODETACHED;
}
knote_post(kn, hint);
}
/* Blast away the entire klist */
if (autodetach) {
klist_init(list);
}
}
/*
* attach a knote to the specified list. Return true if this is the first entry.
* The list is protected by whatever lock the object it is associated with uses.
*/
int
knote_attach(struct klist *list, struct knote *kn)
{
int ret = SLIST_EMPTY(list);
SLIST_INSERT_HEAD(list, kn, kn_selnext);
return ret;
}
/*
* detach a knote from the specified list. Return true if that was the last
* entry. The list is protected by whatever lock the object it is associated
* with uses.
*/
int
knote_detach(struct klist *list, struct knote *kn)
{
assert(!KNOTE_IS_AUTODETACHED(kn));
SLIST_REMOVE(list, kn, knote, kn_selnext);
return SLIST_EMPTY(list);
}
/*
* knote_vanish - Indicate that the source has vanished
*
* Used only for vanishing ports - vanishing fds go
* through knote_fdclose()
*
* If the knote has requested EV_VANISHED delivery,
* arrange for that. Otherwise, deliver a NOTE_REVOKE
* event for backward compatibility.
*
* The knote is marked as having vanished. The source's
* reference to the knote is dropped by caller, but the knote's
* source reference is only cleaned up later when the knote is dropped.
*
* Our caller already has the object lock held. Calling
* the detach routine would try to take that lock
* recursively - which likely is not supported.
*/
void
knote_vanish(struct klist *list, bool make_active)
{
struct knote *kn;
struct knote *kn_next;
SLIST_FOREACH_SAFE(kn, list, kn_selnext, kn_next) {
struct kqueue *kq = knote_get_kq(kn);
kqlock(kq);
if (__probable(kn->kn_status & KN_REQVANISH)) {
/*
* If EV_VANISH supported - prepare to deliver one
*/
kn->kn_status |= KN_VANISHED;
} else {
/*
* Handle the legacy way to indicate that the port/portset was
* deallocated or left the current Mach portspace (modern technique
* is with an EV_VANISHED protocol).
*
* Deliver an EV_EOF event for these changes (hopefully it will get
* delivered before the port name recycles to the same generation
* count and someone tries to re-register a kevent for it or the
* events are udata-specific - avoiding a conflict).
*/
kn->kn_flags |= EV_EOF | EV_ONESHOT;
}
if (make_active) {
knote_activate(kq, kn, FILTER_ACTIVE);
}
kqunlock(kq);
}
}
/*
* remove all knotes referencing a specified fd
*
* Entered with the proc_fd lock already held.
* It returns the same way, but may drop it temporarily.
*/
void
knote_fdclose(struct proc *p, int fd)
{
struct filedesc *fdt = &p->p_fd;
struct klist *list;
struct knote *kn;
KNOTE_LOCK_CTX(knlc);
restart:
list = &fdt->fd_knlist[fd];
SLIST_FOREACH(kn, list, kn_link) {
struct kqueue *kq = knote_get_kq(kn);
kqlock(kq);
if (kq->kq_p != p) {
panic("%s: proc mismatch (kq->kq_p=%p != p=%p)",
__func__, kq->kq_p, p);
}
/*
* If the knote supports EV_VANISHED delivery,
* transition it to vanished mode (or skip over
* it if already vanished).
*/
if (kn->kn_status & KN_VANISHED) {
kqunlock(kq);
continue;
}
proc_fdunlock(p);
if (!knote_lock(kq, kn, &knlc, KNOTE_KQ_LOCK_ON_SUCCESS)) {
/* the knote was dropped by someone, nothing to do */
} else if (kn->kn_status & KN_REQVANISH) {
/*
* Since we have REQVANISH for this knote, we need to notify clients about
* the EV_VANISHED.
*
* But unlike mach ports, we want to do the detach here as well and not
* defer it so that we can release the iocount that is on the knote and
* close the fp.
*/
kn->kn_status |= KN_VANISHED;
/*
* There may be a concurrent post happening, make sure to wait for it
* before we detach. knote_wait_for_post() unlocks on kq on exit
*/
knote_wait_for_post(kq, kn);
knote_fops(kn)->f_detach(kn);
if (kn->kn_is_fd) {
fp_drop(p, (int)kn->kn_id, kn->kn_fp, 0);
}
kn->kn_filtid = EVFILTID_DETACHED;
kqlock(kq);
knote_activate(kq, kn, FILTER_ACTIVE);
knote_unlock(kq, kn, &knlc, KNOTE_KQ_UNLOCK);
} else {
knote_drop(kq, kn, &knlc);
}
proc_fdlock(p);
goto restart;
}
}
/*
* knote_fdfind - lookup a knote in the fd table for process
*
* If the filter is file-based, lookup based on fd index.
* Otherwise use a hash based on the ident.
*
* Matching is based on kq, filter, and ident. Optionally,
* it may also be based on the udata field in the kevent -
* allowing multiple event registration for the file object
* per kqueue.
*
* fd_knhashlock or fdlock held on entry (and exit)
*/
static struct knote *
knote_fdfind(struct kqueue *kq,
const struct kevent_internal_s *kev,
bool is_fd,
struct proc *p)
{
struct filedesc *fdp = &p->p_fd;
struct klist *list = NULL;
struct knote *kn = NULL;
/*
* determine where to look for the knote
*/
if (is_fd) {
/* fd-based knotes are linked off the fd table */
if (kev->kei_ident < (u_int)fdp->fd_knlistsize) {
list = &fdp->fd_knlist[kev->kei_ident];
}
} else if (fdp->fd_knhashmask != 0) {
/* hash non-fd knotes here too */
list = &fdp->fd_knhash[KN_HASH((u_long)kev->kei_ident, fdp->fd_knhashmask)];
}
/*
* scan the selected list looking for a match
*/
if (list != NULL) {
SLIST_FOREACH(kn, list, kn_link) {
if (kq == knote_get_kq(kn) &&
kev->kei_ident == kn->kn_id &&
kev->kei_filter == kn->kn_filter) {
if (kev->kei_flags & EV_UDATA_SPECIFIC) {
if ((kn->kn_flags & EV_UDATA_SPECIFIC) &&
kev->kei_udata == kn->kn_udata) {
break; /* matching udata-specific knote */
}
} else if ((kn->kn_flags & EV_UDATA_SPECIFIC) == 0) {
break; /* matching non-udata-specific knote */
}
}
}
}
return kn;
}
/*
* kq_add_knote- Add knote to the fd table for process
* while checking for duplicates.
*
* All file-based filters associate a list of knotes by file
* descriptor index. All other filters hash the knote by ident.
*
* May have to grow the table of knote lists to cover the
* file descriptor index presented.
*
* fd_knhashlock and fdlock unheld on entry (and exit).
*
* Takes a rwlock boost if inserting the knote is successful.
*/
static int
kq_add_knote(struct kqueue *kq, struct knote *kn, struct knote_lock_ctx *knlc,
struct proc *p)
{
struct filedesc *fdp = &p->p_fd;
struct klist *list = NULL;
int ret = 0;
bool is_fd = kn->kn_is_fd;
if (is_fd) {
proc_fdlock(p);
} else {
knhash_lock(fdp);
}
if (knote_fdfind(kq, &kn->kn_kevent, is_fd, p) != NULL) {
/* found an existing knote: we can't add this one */
ret = ERESTART;
goto out_locked;
}
/* knote was not found: add it now */
if (!is_fd) {
if (fdp->fd_knhashmask == 0) {
u_long size = 0;
list = hashinit(CONFIG_KN_HASHSIZE, M_KQUEUE, &size);
if (list == NULL) {
ret = ENOMEM;
goto out_locked;
}
fdp->fd_knhash = list;
fdp->fd_knhashmask = size;
}
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
SLIST_INSERT_HEAD(list, kn, kn_link);
ret = 0;
goto out_locked;
} else {
/* knote is fd based */
if ((u_int)fdp->fd_knlistsize <= kn->kn_id) {
u_int size = 0;
/* Make sure that fd stays below current process's soft limit AND system allowed per-process limits */
if (kn->kn_id >= (uint64_t)proc_limitgetcur_nofile(p)) {
ret = EINVAL;
goto out_locked;
}
/* have to grow the fd_knlist */
size = fdp->fd_knlistsize;
while (size <= kn->kn_id) {
size += KQEXTENT;
}
if (size >= (UINT_MAX / sizeof(struct klist))) {
ret = EINVAL;
goto out_locked;
}
list = kalloc_type(struct klist, size, Z_WAITOK | Z_ZERO);
if (list == NULL) {
ret = ENOMEM;
goto out_locked;
}
bcopy(fdp->fd_knlist, list,
fdp->fd_knlistsize * sizeof(struct klist));
kfree_type(struct klist, fdp->fd_knlistsize, fdp->fd_knlist);
fdp->fd_knlist = list;
fdp->fd_knlistsize = size;
}
list = &fdp->fd_knlist[kn->kn_id];
SLIST_INSERT_HEAD(list, kn, kn_link);
ret = 0;
goto out_locked;
}
out_locked:
if (ret == 0) {
kqlock(kq);
assert((kn->kn_status & KN_LOCKED) == 0);
(void)knote_lock(kq, kn, knlc, KNOTE_KQ_UNLOCK);
kqueue_retain(kq); /* retain a kq ref */
}
if (is_fd) {
proc_fdunlock(p);
} else {
knhash_unlock(fdp);
}
return ret;
}
/*
* kq_remove_knote - remove a knote from the fd table for process
*
* If the filter is file-based, remove based on fd index.
* Otherwise remove from the hash based on the ident.
*
* fd_knhashlock and fdlock unheld on entry (and exit).
*/
static void
kq_remove_knote(struct kqueue *kq, struct knote *kn, struct proc *p,
struct knote_lock_ctx *knlc)
{
struct filedesc *fdp = &p->p_fd;
struct klist *list = NULL;
uint16_t kq_state;
bool is_fd = kn->kn_is_fd;
if (is_fd) {
proc_fdlock(p);
} else {
knhash_lock(fdp);
}
if (is_fd) {
assert((u_int)fdp->fd_knlistsize > kn->kn_id);
list = &fdp->fd_knlist[kn->kn_id];
} else {
list = &fdp->fd_knhash[KN_HASH(kn->kn_id, fdp->fd_knhashmask)];
}
SLIST_REMOVE(list, kn, knote, kn_link);
kqlock(kq);
/* Update the servicer iotier override */
kqueue_update_iotier_override(kq);
kq_state = kq->kq_state;
if (knlc) {
knote_unlock_cancel(kq, kn, knlc);
} else {
kqunlock(kq);
}
if (is_fd) {
proc_fdunlock(p);
} else {
knhash_unlock(fdp);
}
if (kq_state & KQ_DYNAMIC) {
kqworkloop_release((struct kqworkloop *)kq);
}
}
/*
* kq_find_knote_and_kq_lock - lookup a knote in the fd table for process
* and, if the knote is found, acquires the kqlock while holding the fd table lock/spinlock.
*
* fd_knhashlock or fdlock unheld on entry (and exit)
*/
static struct knote *
kq_find_knote_and_kq_lock(struct kqueue *kq, struct kevent_qos_s *kev,
bool is_fd, struct proc *p)
{
struct filedesc *fdp = &p->p_fd;
struct knote *kn;
if (is_fd) {
proc_fdlock(p);
} else {
knhash_lock(fdp);
}
/*
* Temporary horrible hack:
* this cast is gross and will go away in a future change.
* It is OK to do because we don't look at xflags/s_fflags,
* and that when we cast down the kev this way,
* the truncated filter field works.
*/
kn = knote_fdfind(kq, (struct kevent_internal_s *)kev, is_fd, p);
if (kn) {
kqlock(kq);
assert(knote_get_kq(kn) == kq);
}
if (is_fd) {
proc_fdunlock(p);
} else {
knhash_unlock(fdp);
}
return kn;
}
static struct kqtailq *
knote_get_tailq(kqueue_t kqu, struct knote *kn)
{
kq_index_t qos_index = kn->kn_qos_index;
if (kqu.kq->kq_state & KQ_WORKLOOP) {
assert(qos_index > 0 && qos_index <= KQWL_NBUCKETS);
return &kqu.kqwl->kqwl_queue[qos_index - 1];
} else if (kqu.kq->kq_state & KQ_WORKQ) {
assert(qos_index > 0 && qos_index <= KQWQ_NBUCKETS);
return &kqu.kqwq->kqwq_queue[qos_index - 1];
} else {
assert(qos_index == QOS_INDEX_KQFILE);
return &kqu.kqf->kqf_queue;
}
}
static void
knote_enqueue(kqueue_t kqu, struct knote *kn)
{
kqlock_held(kqu);
if ((kn->kn_status & KN_ACTIVE) == 0) {
return;
}
if (kn->kn_status & (KN_DISABLED | KN_SUPPRESSED | KN_DROPPING | KN_QUEUED)) {
return;
}
struct kqtailq *queue = knote_get_tailq(kqu, kn);
bool wakeup = TAILQ_EMPTY(queue);
TAILQ_INSERT_TAIL(queue, kn, kn_tqe);
kn->kn_status |= KN_QUEUED;
kqu.kq->kq_count++;
if (wakeup) {
if (kqu.kq->kq_state & KQ_WORKLOOP) {
kqworkloop_wakeup(kqu.kqwl, kn->kn_qos_index);
} else if (kqu.kq->kq_state & KQ_WORKQ) {
kqworkq_wakeup(kqu.kqwq, kn->kn_qos_index);
} else {
kqfile_wakeup(kqu.kqf, 0, THREAD_AWAKENED);
}
}
}
__attribute__((always_inline))
static inline void
knote_dequeue(kqueue_t kqu, struct knote *kn)
{
if (kn->kn_status & KN_QUEUED) {
struct kqtailq *queue = knote_get_tailq(kqu, kn);
// attaching the knote calls knote_reset_priority() without
// the kqlock which is fine, so we can't call kqlock_held()
// if we're not queued.
kqlock_held(kqu);
TAILQ_REMOVE(queue, kn, kn_tqe);
kn->kn_status &= ~KN_QUEUED;
kqu.kq->kq_count--;
if ((kqu.kq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0) {
assert((kqu.kq->kq_count == 0) ==
(bool)TAILQ_EMPTY(queue));
}
}
}
/* called with kqueue lock held */
static void
knote_suppress(kqueue_t kqu, struct knote *kn)
{
struct kqtailq *suppressq;
kqlock_held(kqu);
assert((kn->kn_status & KN_SUPPRESSED) == 0);
assert(kn->kn_status & KN_QUEUED);
knote_dequeue(kqu, kn);
/* deactivate - so new activations indicate a wakeup */
kn->kn_status &= ~KN_ACTIVE;
kn->kn_status |= KN_SUPPRESSED;
suppressq = kqueue_get_suppressed_queue(kqu, kn);
TAILQ_INSERT_TAIL(suppressq, kn, kn_tqe);
}
__attribute__((always_inline))
static inline void
knote_unsuppress_noqueue(kqueue_t kqu, struct knote *kn)
{
struct kqtailq *suppressq;
kqlock_held(kqu);
assert(kn->kn_status & KN_SUPPRESSED);
kn->kn_status &= ~KN_SUPPRESSED;
suppressq = kqueue_get_suppressed_queue(kqu, kn);
TAILQ_REMOVE(suppressq, kn, kn_tqe);
/*
* If the knote is no longer active, reset its push,
* and resynchronize kn_qos_index with kn_qos_override
* for knotes with a real qos.
*/
if ((kn->kn_status & KN_ACTIVE) == 0 && knote_has_qos(kn)) {
kn->kn_qos_override = _pthread_priority_thread_qos_fast(kn->kn_qos);
}
kn->kn_qos_index = kn->kn_qos_override;
}
/* called with kqueue lock held */
static void
knote_unsuppress(kqueue_t kqu, struct knote *kn)
{
knote_unsuppress_noqueue(kqu, kn);
knote_enqueue(kqu, kn);
}
__attribute__((always_inline))
static inline void
knote_mark_active(struct knote *kn)
{
if ((kn->kn_status & KN_ACTIVE) == 0) {
KDBG_DEBUG(KEV_EVTID(BSD_KEVENT_KNOTE_ACTIVATE),
kn->kn_udata, kn->kn_status | (kn->kn_id << 32),
kn->kn_filtid);
}
kn->kn_status |= KN_ACTIVE;
}
/* called with kqueue lock held */
static void
knote_activate(kqueue_t kqu, struct knote *kn, int result)
{
assert(result & FILTER_ACTIVE);
if (result & FILTER_ADJUST_EVENT_QOS_BIT) {
// may dequeue the knote
knote_adjust_qos(kqu.kq, kn, result);
}
knote_mark_active(kn);
knote_enqueue(kqu, kn);
}
/*
* This function applies changes requested by f_attach or f_touch for
* a given filter. It proceeds in a carefully chosen order to help
* every single transition do the minimal amount of work possible.
*/
static void
knote_apply_touch(kqueue_t kqu, struct knote *kn, struct kevent_qos_s *kev,
int result)
{
if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) {
kn->kn_status &= ~KN_DISABLED;
/*
* it is possible for userland to have knotes registered for a given
* workloop `wl_orig` but really handled on another workloop `wl_new`.
*
* In that case, rearming will happen from the servicer thread of
* `wl_new` which if `wl_orig` is no longer being serviced, would cause
* this knote to stay suppressed forever if we only relied on
* kqworkloop_acknowledge_events to be called by `wl_orig`.
*
* However if we see the KQ_PROCESSING bit on `wl_orig` set, we can't
* unsuppress because that would mess with the processing phase of
* `wl_orig`, however it also means kqworkloop_acknowledge_events()
* will be called.
*/
if (__improbable(kn->kn_status & KN_SUPPRESSED)) {
if ((kqu.kq->kq_state & KQ_PROCESSING) == 0) {
knote_unsuppress_noqueue(kqu, kn);
}
}
}
if (result & FILTER_ADJUST_EVENT_IOTIER_BIT) {
kqueue_update_iotier_override(kqu);
}
if ((result & FILTER_UPDATE_REQ_QOS) && kev->qos && kev->qos != kn->kn_qos) {
// may dequeue the knote
knote_reset_priority(kqu, kn, kev->qos);
}
/*
* When we unsuppress above, or because of knote_reset_priority(),
* the knote may have been dequeued, we need to restore the invariant
* that if the knote is active it needs to be queued now that
* we're done applying changes.
*/
if (result & FILTER_ACTIVE) {
knote_activate(kqu, kn, result);
} else {
knote_enqueue(kqu, kn);
}
if ((result & FILTER_THREADREQ_NODEFEER) &&
act_clear_astkevent(current_thread(), AST_KEVENT_REDRIVE_THREADREQ)) {
workq_kern_threadreq_redrive(kqu.kq->kq_p, WORKQ_THREADREQ_NONE);
}
}
/*
* knote_drop - disconnect and drop the knote
*
* Called with the kqueue locked, returns with the kqueue unlocked.
*
* If a knote locking context is passed, it is canceled.
*
* The knote may have already been detached from
* (or not yet attached to) its source object.
*/
static void
knote_drop(struct kqueue *kq, struct knote *kn, struct knote_lock_ctx *knlc)
{
struct proc *p = kq->kq_p;
kqlock_held(kq);
assert((kn->kn_status & KN_DROPPING) == 0);
if (knlc == NULL) {
assert((kn->kn_status & KN_LOCKED) == 0);
}
kn->kn_status |= KN_DROPPING;
if (kn->kn_status & KN_SUPPRESSED) {
knote_unsuppress_noqueue(kq, kn);
} else {
knote_dequeue(kq, kn);
}
knote_wait_for_post(kq, kn);
/* Even if we are autodetached, the filter may need to do cleanups of any
* stuff stashed on the knote so always make the call and let each filter
* handle the possibility of autodetached-ness */
knote_fops(kn)->f_detach(kn);
/* kq may be freed when kq_remove_knote() returns */
kq_remove_knote(kq, kn, p, knlc);
if (kn->kn_is_fd && ((kn->kn_status & KN_VANISHED) == 0)) {
fp_drop(p, (int)kn->kn_id, kn->kn_fp, 0);
}
knote_free(kn);
}
void
knote_init(void)
{
#if CONFIG_MEMORYSTATUS
/* Initialize the memorystatus list lock */
memorystatus_kevent_init(&kq_lck_grp, LCK_ATTR_NULL);
#endif
}
SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL);
const struct filterops *
knote_fops(struct knote *kn)
{
return sysfilt_ops[kn->kn_filtid];
}
static struct knote *
knote_alloc(void)
{
return zalloc_flags(knote_zone, Z_WAITOK | Z_ZERO | Z_NOFAIL);
}
static void
knote_free(struct knote *kn)
{
assert((kn->kn_status & (KN_LOCKED | KN_POSTING)) == 0);
zfree(knote_zone, kn);
}
#pragma mark - syscalls: kevent, kevent64, kevent_qos, kevent_id
kevent_ctx_t
kevent_get_context(thread_t thread)
{
uthread_t ut = get_bsdthread_info(thread);
return &ut->uu_save.uus_kevent;
}
static inline bool
kevent_args_requesting_events(unsigned int flags, int nevents)
{
return !(flags & KEVENT_FLAG_ERROR_EVENTS) && nevents > 0;
}
static inline int
kevent_adjust_flags_for_proc(proc_t p, int flags)
{
__builtin_assume(p);
return flags | (IS_64BIT_PROCESS(p) ? KEVENT_FLAG_PROC64 : 0);
}
/*!
* @function kevent_get_kqfile
*
* @brief
* Lookup a kqfile by fd.
*
* @discussion
* Callers: kevent, kevent64, kevent_qos
*
* This is not assumed to be a fastpath (kqfile interfaces are legacy)
*/
OS_NOINLINE
static int
kevent_get_kqfile(struct proc *p, int fd, int flags,
struct fileproc **fpp, struct kqueue **kqp)
{
int error = 0;
struct kqueue *kq;
error = fp_get_ftype(p, fd, DTYPE_KQUEUE, EBADF, fpp);
if (__improbable(error)) {
return error;
}
kq = (struct kqueue *)fp_get_data((*fpp));
uint16_t kq_state = os_atomic_load(&kq->kq_state, relaxed);
if (__improbable((kq_state & (KQ_KEV32 | KQ_KEV64 | KQ_KEV_QOS)) == 0)) {
kqlock(kq);
kq_state = kq->kq_state;
if (!(kq_state & (KQ_KEV32 | KQ_KEV64 | KQ_KEV_QOS))) {
if (flags & KEVENT_FLAG_LEGACY32) {
kq_state |= KQ_KEV32;
} else if (flags & KEVENT_FLAG_LEGACY64) {
kq_state |= KQ_KEV64;
} else {
kq_state |= KQ_KEV_QOS;
}
kq->kq_state = kq_state;
}
kqunlock(kq);
}
/*
* kqfiles can't be used through the legacy kevent()
* and other interfaces at the same time.
*/
if (__improbable((bool)(flags & KEVENT_FLAG_LEGACY32) !=
(bool)(kq_state & KQ_KEV32))) {
fp_drop(p, fd, *fpp, 0);
return EINVAL;
}
*kqp = kq;
return 0;
}
/*!
* @function kevent_get_kqwq
*
* @brief
* Lookup or create the process kqwq (faspath).
*
* @discussion
* Callers: kevent64, kevent_qos
*/
OS_ALWAYS_INLINE
static int
kevent_get_kqwq(proc_t p, int flags, int nevents, struct kqueue **kqp)
{
struct kqworkq *kqwq = p->p_fd.fd_wqkqueue;
if (__improbable(kevent_args_requesting_events(flags, nevents))) {
return EINVAL;
}
if (__improbable(kqwq == NULL)) {
kqwq = kqworkq_alloc(p, flags);
if (__improbable(kqwq == NULL)) {
return ENOMEM;
}
}
*kqp = &kqwq->kqwq_kqueue;
return 0;
}
#pragma mark kevent copyio
/*!
* @function kevent_get_data_size
*
* @brief
* Copies in the extra data size from user-space.
*/
static int
kevent_get_data_size(int flags, user_addr_t data_avail, user_addr_t data_out,
kevent_ctx_t kectx)
{
if (!data_avail || !data_out) {
kectx->kec_data_size = 0;
kectx->kec_data_resid = 0;
} else if (flags & KEVENT_FLAG_PROC64) {
user64_size_t usize = 0;
int error = copyin((user_addr_t)data_avail, &usize, sizeof(usize));
if (__improbable(error)) {
return error;
}
kectx->kec_data_resid = kectx->kec_data_size = (user_size_t)usize;
} else {
user32_size_t usize = 0;
int error = copyin((user_addr_t)data_avail, &usize, sizeof(usize));
if (__improbable(error)) {
return error;
}
kectx->kec_data_avail = data_avail;
kectx->kec_data_resid = kectx->kec_data_size = (user_size_t)usize;
}
kectx->kec_data_out = data_out;
kectx->kec_data_avail = data_avail;
return 0;
}
/*!
* @function kevent_put_data_size
*
* @brief
* Copies out the residual data size to user-space if any has been used.
*/
static int
kevent_put_data_size(unsigned int flags, kevent_ctx_t kectx)
{
if (kectx->kec_data_resid == kectx->kec_data_size) {
return 0;
}
if (flags & KEVENT_FLAG_KERNEL) {
*(user_size_t *)(uintptr_t)kectx->kec_data_avail = kectx->kec_data_resid;
return 0;
}
if (flags & KEVENT_FLAG_PROC64) {
user64_size_t usize = (user64_size_t)kectx->kec_data_resid;
return copyout(&usize, (user_addr_t)kectx->kec_data_avail, sizeof(usize));
} else {
user32_size_t usize = (user32_size_t)kectx->kec_data_resid;
return copyout(&usize, (user_addr_t)kectx->kec_data_avail, sizeof(usize));
}
}
/*!
* @function kevent_legacy_copyin
*
* @brief
* Handles the copyin of a kevent/kevent64 event.
*/
static int
kevent_legacy_copyin(user_addr_t *addrp, struct kevent_qos_s *kevp, unsigned int flags)
{
int error;
assert((flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64)) != 0);
if (flags & KEVENT_FLAG_LEGACY64) {
struct kevent64_s kev64;
error = copyin(*addrp, (caddr_t)&kev64, sizeof(kev64));
if (__improbable(error)) {
return error;
}
*addrp += sizeof(kev64);
*kevp = (struct kevent_qos_s){
.ident = kev64.ident,
.filter = kev64.filter,
/* Make sure user doesn't pass in any system flags */
.flags = kev64.flags & ~EV_SYSFLAGS,
.udata = kev64.udata,
.fflags = kev64.fflags,
.data = kev64.data,
.ext[0] = kev64.ext[0],
.ext[1] = kev64.ext[1],
};
} else if (flags & KEVENT_FLAG_PROC64) {
struct user64_kevent kev64;
error = copyin(*addrp, (caddr_t)&kev64, sizeof(kev64));
if (__improbable(error)) {
return error;
}
*addrp += sizeof(kev64);
*kevp = (struct kevent_qos_s){
.ident = kev64.ident,
.filter = kev64.filter,
/* Make sure user doesn't pass in any system flags */
.flags = kev64.flags & ~EV_SYSFLAGS,
.udata = kev64.udata,
.fflags = kev64.fflags,
.data = kev64.data,
};
} else {
struct user32_kevent kev32;
error = copyin(*addrp, (caddr_t)&kev32, sizeof(kev32));
if (__improbable(error)) {
return error;
}
*addrp += sizeof(kev32);
*kevp = (struct kevent_qos_s){
.ident = (uintptr_t)kev32.ident,
.filter = kev32.filter,
/* Make sure user doesn't pass in any system flags */
.flags = kev32.flags & ~EV_SYSFLAGS,
.udata = CAST_USER_ADDR_T(kev32.udata),
.fflags = kev32.fflags,
.data = (intptr_t)kev32.data,
};
}
return 0;
}
/*!
* @function kevent_modern_copyin
*
* @brief
* Handles the copyin of a kevent_qos/kevent_id event.
*/
static int
kevent_modern_copyin(user_addr_t *addrp, struct kevent_qos_s *kevp)
{
int error = copyin(*addrp, (caddr_t)kevp, sizeof(struct kevent_qos_s));
if (__probable(!error)) {
/* Make sure user doesn't pass in any system flags */
*addrp += sizeof(struct kevent_qos_s);
kevp->flags &= ~EV_SYSFLAGS;
}
return error;
}
/*!
* @function kevent_legacy_copyout
*
* @brief
* Handles the copyout of a kevent/kevent64 event.
*/
static int
kevent_legacy_copyout(struct kevent_qos_s *kevp, user_addr_t *addrp, unsigned int flags)
{
int advance;
int error;
assert((flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64)) != 0);
/*
* fully initialize the differnt output event structure
* types from the internal kevent (and some universal
* defaults for fields not represented in the internal
* form).
*
* Note: these structures have no padding hence the C99
* initializers below do not leak kernel info.
*/
if (flags & KEVENT_FLAG_LEGACY64) {
struct kevent64_s kev64 = {
.ident = kevp->ident,
.filter = kevp->filter,
.flags = kevp->flags,
.fflags = kevp->fflags,
.data = (int64_t)kevp->data,
.udata = kevp->udata,
.ext[0] = kevp->ext[0],
.ext[1] = kevp->ext[1],
};
advance = sizeof(struct kevent64_s);
error = copyout((caddr_t)&kev64, *addrp, advance);
} else if (flags & KEVENT_FLAG_PROC64) {
/*
* deal with the special case of a user-supplied
* value of (uintptr_t)-1.
*/
uint64_t ident = (kevp->ident == (uintptr_t)-1) ?
(uint64_t)-1LL : (uint64_t)kevp->ident;
struct user64_kevent kev64 = {
.ident = ident,
.filter = kevp->filter,
.flags = kevp->flags,
.fflags = kevp->fflags,
.data = (int64_t) kevp->data,
.udata = (user_addr_t) kevp->udata,
};
advance = sizeof(kev64);
error = copyout((caddr_t)&kev64, *addrp, advance);
} else {
struct user32_kevent kev32 = {
.ident = (uint32_t)kevp->ident,
.filter = kevp->filter,
.flags = kevp->flags,
.fflags = kevp->fflags,
.data = (int32_t)kevp->data,
.udata = (uint32_t)kevp->udata,
};
advance = sizeof(kev32);
error = copyout((caddr_t)&kev32, *addrp, advance);
}
if (__probable(!error)) {
*addrp += advance;
}
return error;
}
/*!
* @function kevent_modern_copyout
*
* @brief
* Handles the copyout of a kevent_qos/kevent_id event.
*/
OS_ALWAYS_INLINE
static inline int
kevent_modern_copyout(struct kevent_qos_s *kevp, user_addr_t *addrp)
{
int error = copyout((caddr_t)kevp, *addrp, sizeof(struct kevent_qos_s));
if (__probable(!error)) {
*addrp += sizeof(struct kevent_qos_s);
}
return error;
}
#pragma mark kevent core implementation
/*!
* @function kevent_callback_inline
*
* @brief
* Callback for each individual event
*
* @discussion
* This is meant to be inlined in kevent_modern_callback and
* kevent_legacy_callback.
*/
OS_ALWAYS_INLINE
static inline int
kevent_callback_inline(struct kevent_qos_s *kevp, kevent_ctx_t kectx, bool legacy)
{
int error;
assert(kectx->kec_process_noutputs < kectx->kec_process_nevents);
/*
* Copy out the appropriate amount of event data for this user.
*/
if (legacy) {
error = kevent_legacy_copyout(kevp, &kectx->kec_process_eventlist,
kectx->kec_process_flags);
} else {
error = kevent_modern_copyout(kevp, &kectx->kec_process_eventlist);
}
/*
* If there isn't space for additional events, return
* a harmless error to stop the processing here
*/
if (error == 0 && ++kectx->kec_process_noutputs == kectx->kec_process_nevents) {
error = EWOULDBLOCK;
}
return error;
}
/*!
* @function kevent_modern_callback
*
* @brief
* Callback for each individual modern event.
*
* @discussion
* This callback handles kevent_qos/kevent_id events.
*/
static int
kevent_modern_callback(struct kevent_qos_s *kevp, kevent_ctx_t kectx)
{
return kevent_callback_inline(kevp, kectx, /*legacy*/ false);
}
/*!
* @function kevent_legacy_callback
*
* @brief
* Callback for each individual legacy event.
*
* @discussion
* This callback handles kevent/kevent64 events.
*/
static int
kevent_legacy_callback(struct kevent_qos_s *kevp, kevent_ctx_t kectx)
{
return kevent_callback_inline(kevp, kectx, /*legacy*/ true);
}
/*!
* @function kevent_cleanup
*
* @brief
* Handles the cleanup returning from a kevent call.
*
* @discussion
* kevent entry points will take a reference on workloops,
* and a usecount on the fileglob of kqfiles.
*
* This function undoes this on the exit paths of kevents.
*
* @returns
* The error to return to userspace.
*/
static int
kevent_cleanup(kqueue_t kqu, int flags, int error, kevent_ctx_t kectx)
{
// poll should not call any codepath leading to this
assert((flags & KEVENT_FLAG_POLL) == 0);
if (flags & KEVENT_FLAG_WORKLOOP) {
kqworkloop_release(kqu.kqwl);
} else if (flags & KEVENT_FLAG_WORKQ) {
/* nothing held */
} else {
fp_drop(kqu.kqf->kqf_p, kectx->kec_fd, kectx->kec_fp, 0);
}
/* don't restart after signals... */
if (error == ERESTART) {
error = EINTR;
} else if (error == 0) {
/* don't abandon other output just because of residual copyout failures */
(void)kevent_put_data_size(flags, kectx);
}
if (flags & KEVENT_FLAG_PARKING) {
thread_t th = current_thread();
struct uthread *uth = get_bsdthread_info(th);
if (uth->uu_kqr_bound) {
thread_unfreeze_base_pri(th);
}
}
return error;
}
/*!
* @function kqueue_process
*
* @brief
* Process the triggered events in a kqueue.
*
* @discussion
* Walk the queued knotes and validate that they are really still triggered
* events by calling the filter routines (if necessary).
*
* For each event that is still considered triggered, invoke the callback
* routine provided.
*
* caller holds a reference on the kqueue.
* kqueue locked on entry and exit - but may be dropped
* kqueue list locked (held for duration of call)
*
* This is only called by kqueue_scan() so that the compiler can inline it.
*
* @returns
* - 0: no event was returned, no other error occured
* - EBADF: the kqueue is being destroyed (KQ_DRAIN is set)
* - EWOULDBLOCK: (not an error) events have been found and we should return
* - EFAULT: copyout failed
* - filter specific errors
*/
static int
kqueue_process(kqueue_t kqu, int flags, kevent_ctx_t kectx,
kevent_callback_t callback)
{
workq_threadreq_t kqr = current_uthread()->uu_kqr_bound;
struct knote *kn;
int error = 0, rc = 0;
struct kqtailq *base_queue, *queue;
uint16_t kq_type = (kqu.kq->kq_state & (KQ_WORKQ | KQ_WORKLOOP));
if (kq_type & KQ_WORKQ) {
rc = kqworkq_begin_processing(kqu.kqwq, kqr, flags);
} else if (kq_type & KQ_WORKLOOP) {
rc = kqworkloop_begin_processing(kqu.kqwl, flags);
} else {
kqfile_retry:
rc = kqfile_begin_processing(kqu.kqf);
if (rc == EBADF) {
return EBADF;
}
}
if (rc == -1) {
/* Nothing to process */
return 0;
}
/*
* loop through the enqueued knotes associated with this request,
* processing each one. Each request may have several queues
* of knotes to process (depending on the type of kqueue) so we
* have to loop through all the queues as long as we have additional
* space.
*/
process_again:
if (kq_type & KQ_WORKQ) {
base_queue = queue = &kqu.kqwq->kqwq_queue[kqr->tr_kq_qos_index - 1];
} else if (kq_type & KQ_WORKLOOP) {
base_queue = &kqu.kqwl->kqwl_queue[0];
queue = &kqu.kqwl->kqwl_queue[KQWL_NBUCKETS - 1];
} else {
base_queue = queue = &kqu.kqf->kqf_queue;
}
do {
while ((kn = TAILQ_FIRST(queue)) != NULL) {
error = knote_process(kn, kectx, callback);
if (error == EJUSTRETURN) {
error = 0;
} else if (__improbable(error)) {
/* error is EWOULDBLOCK when the out event array is full */
goto stop_processing;
}
}
} while (queue-- > base_queue);
if (kectx->kec_process_noutputs) {
/* callers will transform this into no error */
error = EWOULDBLOCK;
}
stop_processing:
/*
* If KEVENT_FLAG_PARKING is set, and no kevents have been returned,
* we want to unbind the kqrequest from the thread.
*
* However, because the kq locks are dropped several times during process,
* new knotes may have fired again, in which case, we want to fail the end
* processing and process again, until it converges.
*
* If we have an error or returned events, end processing never fails.
*/
if (error) {
flags &= ~KEVENT_FLAG_PARKING;
}
if (kq_type & KQ_WORKQ) {
rc = kqworkq_end_processing(kqu.kqwq, kqr, flags);
} else if (kq_type & KQ_WORKLOOP) {
rc = kqworkloop_end_processing(kqu.kqwl, KQ_PROCESSING, flags);
} else {
rc = kqfile_end_processing(kqu.kqf);
}
if (__probable(error)) {
return error;
}
if (__probable(rc >= 0)) {
assert(rc == 0 || rc == EBADF);
return rc;
}
if (kq_type & (KQ_WORKQ | KQ_WORKLOOP)) {
assert(flags & KEVENT_FLAG_PARKING);
goto process_again;
} else {
goto kqfile_retry;
}
}
/*!
* @function kqueue_scan_continue
*
* @brief
* The continuation used by kqueue_scan for kevent entry points.
*
* @discussion
* Assumes we inherit a use/ref count on the kq or its fileglob.
*
* This is called by kqueue_scan if neither KEVENT_FLAG_POLL nor
* KEVENT_FLAG_KERNEL was set, and the caller had to wait.
*/
OS_NORETURN OS_NOINLINE
static void
kqueue_scan_continue(void *data, wait_result_t wait_result)
{
uthread_t ut = current_uthread();
kevent_ctx_t kectx = &ut->uu_save.uus_kevent;
int error = 0, flags = kectx->kec_process_flags;
struct kqueue *kq = data;
/*
* only kevent variants call in here, so we know the callback is
* kevent_legacy_callback or kevent_modern_callback.
*/
assert((flags & (KEVENT_FLAG_POLL | KEVENT_FLAG_KERNEL)) == 0);
switch (wait_result) {
case THREAD_AWAKENED:
if (__improbable(flags & (KEVENT_FLAG_LEGACY32 | KEVENT_FLAG_LEGACY64))) {
error = kqueue_scan(kq, flags, kectx, kevent_legacy_callback);
} else {
error = kqueue_scan(kq, flags, kectx, kevent_modern_callback);
}
break;
case THREAD_TIMED_OUT:
error = 0;
break;
case THREAD_INTERRUPTED:
error = EINTR;
break;
case THREAD_RESTART:
error = EBADF;
break;
default:
panic("%s: - invalid wait_result (%d)", __func__, wait_result);
}
error = kevent_cleanup(kq, flags, error, kectx);
*(int32_t *)&ut->uu_rval = kectx->kec_process_noutputs;
unix_syscall_return(error);
}
/*!
* @function kqueue_scan
*
* @brief
* Scan and wait for events in a kqueue (used by poll & kevent).
*
* @discussion
* Process the triggered events in a kqueue.
*
* If there are no events triggered arrange to wait for them:
* - unless KEVENT_FLAG_IMMEDIATE is set in kectx->kec_process_flags
* - possibly until kectx->kec_deadline expires
*
* When it waits, and that neither KEVENT_FLAG_POLL nor KEVENT_FLAG_KERNEL
* are set, then it will wait in the kqueue_scan_continue continuation.
*
* poll() will block in place, and KEVENT_FLAG_KERNEL calls
* all pass KEVENT_FLAG_IMMEDIATE and will not wait.
*
* @param kqu
* The kqueue being scanned.
*
* @param flags
* The KEVENT_FLAG_* flags for this call.
*
* @param kectx
* The context used for this scan.
* The uthread_t::uu_save.uus_kevent storage is used for this purpose.
*
* @param callback
* The callback to be called on events sucessfully processed.
* (Either kevent_legacy_callback, kevent_modern_callback or poll_callback)
*/
int
kqueue_scan(kqueue_t kqu, int flags, kevent_ctx_t kectx,
kevent_callback_t callback)
{
int error;
for (;;) {
kqlock(kqu);
error = kqueue_process(kqu, flags, kectx, callback);
/*
* If we got an error, events returned (EWOULDBLOCK)
* or blocking was disallowed (KEVENT_FLAG_IMMEDIATE),
* just return.
*/
if (__probable(error || (flags & KEVENT_FLAG_IMMEDIATE))) {
kqunlock(kqu);
return error == EWOULDBLOCK ? 0 : error;
}
assert((kqu.kq->kq_state & (KQ_WORKQ | KQ_WORKLOOP)) == 0);
kqu.kqf->kqf_state |= KQ_SLEEP;
assert_wait_deadline(&kqu.kqf->kqf_count, THREAD_ABORTSAFE,
kectx->kec_deadline);
kqunlock(kqu);
if (__probable((flags & (KEVENT_FLAG_POLL | KEVENT_FLAG_KERNEL)) == 0)) {
thread_block_parameter(kqueue_scan_continue, kqu.kqf);
__builtin_unreachable();
}
wait_result_t wr = thread_block(THREAD_CONTINUE_NULL);
switch (wr) {
case THREAD_AWAKENED:
break;
case THREAD_TIMED_OUT:
return 0;
case THREAD_INTERRUPTED:
return EINTR;
case THREAD_RESTART:
return EBADF;
default:
panic("%s: - bad wait_result (%d)", __func__, wr);
}
}
}
/*!
* @function kevent_internal
*
* @brief
* Common kevent code.
*
* @discussion
* Needs to be inlined to specialize for legacy or modern and
* eliminate dead code.
*
* This is the core logic of kevent entry points, that will:
* - register kevents
* - optionally scan the kqueue for events
*
* The caller is giving kevent_internal a reference on the kqueue
* or its fileproc that needs to be cleaned up by kevent_cleanup().
*/
OS_ALWAYS_INLINE
static inline int
kevent_internal(kqueue_t kqu,
user_addr_t changelist, int nchanges,
user_addr_t ueventlist, int nevents,
int flags, kevent_ctx_t kectx, int32_t *retval,
bool legacy)
{
int error = 0, noutputs = 0, register_rc;
/* only bound threads can receive events on workloops */
if (!legacy && (flags & KEVENT_FLAG_WORKLOOP)) {
#if CONFIG_WORKLOOP_DEBUG
UU_KEVENT_HISTORY_WRITE_ENTRY(current_uthread(), {
.uu_kqid = kqu.kqwl->kqwl_dynamicid,
.uu_kq = error ? NULL : kqu.kq,
.uu_error = error,
.uu_nchanges = nchanges,
.uu_nevents = nevents,
.uu_flags = flags,
});
#endif // CONFIG_WORKLOOP_DEBUG
if (flags & KEVENT_FLAG_KERNEL) {
/* see kevent_workq_internal */
error = copyout(&kqu.kqwl->kqwl_dynamicid,
ueventlist - sizeof(kqueue_id_t), sizeof(kqueue_id_t));
kectx->kec_data_resid -= sizeof(kqueue_id_t);
if (__improbable(error)) {
goto out;
}
}
if (kevent_args_requesting_events(flags, nevents)) {
/*
* Disable the R2K notification while doing a register, if the
* caller wants events too, we don't want the AST to be set if we
* will process these events soon.
*/
kqlock(kqu);
kqu.kq->kq_state &= ~KQ_R2K_ARMED;
kqunlock(kqu);
flags |= KEVENT_FLAG_NEEDS_END_PROCESSING;
}
}
/* register all the change requests the user provided... */
while (nchanges > 0 && error == 0) {
struct kevent_qos_s kev;
struct knote *kn = NULL;
if (legacy) {
error = kevent_legacy_copyin(&changelist, &kev, flags);
} else {
error = kevent_modern_copyin(&changelist, &kev);
}
if (error) {
break;
}
register_rc = kevent_register(kqu.kq, &kev, &kn);
if (__improbable(!legacy && (register_rc & FILTER_REGISTER_WAIT))) {
thread_t thread = current_thread();
kqlock_held(kqu);
if (act_clear_astkevent(thread, AST_KEVENT_REDRIVE_THREADREQ)) {
workq_kern_threadreq_redrive(kqu.kq->kq_p, WORKQ_THREADREQ_NONE);
}
// f_post_register_wait is meant to call a continuation and not to
// return, which is why we don't support FILTER_REGISTER_WAIT if
// KEVENT_FLAG_ERROR_EVENTS is not passed, or if the event that
// waits isn't the last.
//
// It is implementable, but not used by any userspace code at the
// moment, so for now return ENOTSUP if someone tries to do it.
if (nchanges == 1 && noutputs < nevents &&
(flags & KEVENT_FLAG_KERNEL) == 0 &&
(flags & KEVENT_FLAG_PARKING) == 0 &&
(flags & KEVENT_FLAG_ERROR_EVENTS) &&
(flags & KEVENT_FLAG_WORKLOOP)) {
uthread_t ut = get_bsdthread_info(thread);
/*
* store the continuation/completion data in the uthread
*
* Note: the kectx aliases with this,
* and is destroyed in the process.
*/
ut->uu_save.uus_kevent_register = (struct _kevent_register){
.kev = kev,
.kqwl = kqu.kqwl,
.eventout = noutputs,
.ueventlist = ueventlist,
};
knote_fops(kn)->f_post_register_wait(ut, kn,
&ut->uu_save.uus_kevent_register);
__builtin_unreachable();
}
kqunlock(kqu);
kev.flags |= EV_ERROR;
kev.data = ENOTSUP;
} else {
assert((register_rc & FILTER_REGISTER_WAIT) == 0);
}
// keep in sync with kevent_register_wait_return()
if (noutputs < nevents && (kev.flags & (EV_ERROR | EV_RECEIPT))) {
if ((kev.flags & EV_ERROR) == 0) {
kev.flags |= EV_ERROR;
kev.data = 0;
}
if (legacy) {
error = kevent_legacy_copyout(&kev, &ueventlist, flags);
} else {
error = kevent_modern_copyout(&kev, &ueventlist);
}
if (error == 0) {
noutputs++;
}
} else if (kev.flags & EV_ERROR) {
error = (int)kev.data;
}
nchanges--;
}
if ((flags & KEVENT_FLAG_ERROR_EVENTS) == 0 &&
nevents > 0 && noutputs == 0 && error == 0) {
kectx->kec_process_flags = flags;
kectx->kec_process_nevents = nevents;
kectx->kec_process_noutputs = 0;
kectx->kec_process_eventlist = ueventlist;
if (legacy) {
error = kqueue_scan(kqu.kq, flags, kectx, kevent_legacy_callback);
} else {
error = kqueue_scan(kqu.kq, flags, kectx, kevent_modern_callback);
}
noutputs = kectx->kec_process_noutputs;
} else if (!legacy && (flags & KEVENT_FLAG_NEEDS_END_PROCESSING)) {
/*
* If we didn't through kqworkloop_end_processing(),
* we need to do it here.
*
* kqueue_scan will call kqworkloop_end_processing(),
* so we only need to do it if we didn't scan.
*/
kqlock(kqu);
kqworkloop_end_processing(kqu.kqwl, 0, 0);
kqunlock(kqu);
}
*retval = noutputs;
out:
return kevent_cleanup(kqu.kq, flags, error, kectx);
}
#pragma mark modern syscalls: kevent_qos, kevent_id, kevent_workq_internal
/*!
* @function kevent_modern_internal
*
* @brief
* The backend of the kevent_id and kevent_workq_internal entry points.
*
* @discussion
* Needs to be inline due to the number of arguments.
*/
OS_NOINLINE
static int
kevent_modern_internal(kqueue_t kqu,
user_addr_t changelist, int nchanges,
user_addr_t ueventlist, int nevents,
int flags, kevent_ctx_t kectx, int32_t *retval)
{
return kevent_internal(kqu.kq, changelist, nchanges,
ueventlist, nevents, flags, kectx, retval, /*legacy*/ false);
}
/*!
* @function kevent_id
*
* @brief
* The kevent_id() syscall.
*/
int
kevent_id(struct proc *p, struct kevent_id_args *uap, int32_t *retval)
{
int error, flags = uap->flags & KEVENT_FLAG_USER;
uthread_t uth = current_uthread();
workq_threadreq_t kqr = uth->uu_kqr_bound;
kevent_ctx_t kectx = &uth->uu_save.uus_kevent;
kqueue_t kqu;
flags = kevent_adjust_flags_for_proc(p, flags);
flags |= KEVENT_FLAG_DYNAMIC_KQUEUE;
if (__improbable((flags & (KEVENT_FLAG_WORKQ | KEVENT_FLAG_WORKLOOP)) !=
KEVENT_FLAG_WORKLOOP)) {
return EINVAL;
}
error = kevent_get_data_size(flags, uap->data_available, uap->data_out, kectx);
if (__improbable(error)) {
return error;
}
kectx->kec_deadline = 0;
kectx->kec_fp = NULL;
kectx->kec_fd = -1;
/* the kec_process_* fields are filled if kqueue_scann is called only */
/*
* Get the kq we are going to be working on
* As a fastpath, look at the currently bound workloop.
*/
kqu.kqwl = kqr ? kqr_kqworkloop(kqr) : NULL;
if (kqu.kqwl && kqu.kqwl->kqwl_dynamicid == uap->id) {
if (__improbable(flags & KEVENT_FLAG_DYNAMIC_KQ_MUST_NOT_EXIST)) {
return EEXIST;
}
kqworkloop_retain(kqu.kqwl);
} else if (__improbable(kevent_args_requesting_events(flags, uap->nevents))) {
return EXDEV;
} else {
error = kqworkloop_get_or_create(p, uap->id, NULL,
#if CONFIG_PREADOPT_TG
NULL,
#endif /* CONFIG_PREADOPT_TG */
flags, &kqu.kqwl);
if (__improbable(error)) {
return error;
}
}
return kevent_modern_internal(kqu, uap->changelist, uap->nchanges,
uap->eventlist, uap->nevents, flags, kectx, retval);
}
/**!
* @function kevent_workq_internal
*
* @discussion
* This function is exported for the sake of the workqueue subsystem.
*
* It is called in two ways:
* - when a thread is about to go to userspace to ask for pending event
* - when a thread is returning from userspace with events back
*
* the workqueue subsystem will only use the following flags:
* - KEVENT_FLAG_STACK_DATA (always)
* - KEVENT_FLAG_IMMEDIATE (always)
* - KEVENT_FLAG_PARKING (depending on whether it is going to or returning from
* userspace).
*
* It implicitly acts on the bound kqueue, and for the case of workloops
* will copyout the kqueue ID before anything else.
*
*
* Pthread will have setup the various arguments to fit this stack layout:
*
* +-------....----+--------------+-----------+--------------------+
* | user stack | data avail | nevents | pthread_self() |
* +-------....----+--------------+-----------+--------------------+
* ^ ^
* data_out eventlist
*
* When a workloop is used, the workloop ID is copied out right before
* the eventlist and is taken from the data buffer.
*
* @warning
* This function is carefuly tailored to not make any call except the final tail
* call into kevent_modern_internal. (LTO inlines current_uthread()).
*
* This function is performance sensitive due to the workq subsystem.
*/
int
kevent_workq_internal(struct proc *p,
user_addr_t changelist, int nchanges,
user_addr_t eventlist, int nevents,
user_addr_t data_out, user_size_t *data_available,
unsigned int flags, int32_t *retval)
{
uthread_t uth = current_uthread();
workq_threadreq_t kqr = uth->uu_kqr_bound;
kevent_ctx_t kectx = &uth->uu_save.uus_kevent;
kqueue_t kqu;
assert(flags == (KEVENT_FLAG_STACK_DATA | KEVENT_FLAG_IMMEDIATE) ||
flags == (KEVENT_FLAG_STACK_DATA | KEVENT_FLAG_IMMEDIATE | KEVENT_FLAG_PARKING));
kectx->kec_data_out = data_out;
kectx->kec_data_avail = (uint64_t)data_available;
kectx->kec_data_size = *data_available;
kectx->kec_data_resid = *data_available;
kectx->kec_deadline = 0;
kectx->kec_fp = NULL;
kectx->kec_fd = -1;
/* the kec_process_* fields are filled if kqueue_scann is called only */
flags = kevent_adjust_flags_for_proc(p, flags);
if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) {
kqu.kqwl = __container_of(kqr, struct kqworkloop, kqwl_request);
kqworkloop_retain(kqu.kqwl);
flags |= KEVENT_FLAG_WORKLOOP | KEVENT_FLAG_DYNAMIC_KQUEUE |
KEVENT_FLAG_KERNEL;
} else {
kqu.kqwq = p->p_fd.fd_wqkqueue;
flags |= KEVENT_FLAG_WORKQ | KEVENT_FLAG_KERNEL;
}
return kevent_modern_internal(kqu, changelist, nchanges,
eventlist, nevents, flags, kectx, retval);
}
/*!
* @function kevent_qos
*
* @brief
* The kevent_qos() syscall.
*/
int
kevent_qos(struct proc *p, struct kevent_qos_args *uap, int32_t *retval)
{
uthread_t uth = current_uthread();
kevent_ctx_t kectx = &uth->uu_save.uus_kevent;
int error, flags = uap->flags & KEVENT_FLAG_USER;
struct kqueue *kq;
if (__improbable(flags & KEVENT_ID_FLAG_USER)) {
return EINVAL;
}
flags = kevent_adjust_flags_for_proc(p, flags);
error = kevent_get_data_size(flags, uap->data_available, uap->data_out, kectx);
if (__improbable(error)) {
return error;
}
kectx->kec_deadline = 0;
kectx->kec_fp = NULL;
kectx->kec_fd = uap->fd;
/* the kec_process_* fields are filled if kqueue_scann is called only */
/* get the kq we are going to be working on */
if (__probable(flags & KEVENT_FLAG_WORKQ)) {
error = kevent_get_kqwq(p, flags, uap->nevents, &kq);
} else {
error = kevent_get_kqfile(p, uap->fd, flags, &kectx->kec_fp, &kq);
}
if (__improbable(error)) {
return error;
}
return kevent_modern_internal(kq, uap->changelist, uap->nchanges,
uap->eventlist, uap->nevents, flags, kectx, retval);
}
#pragma mark legacy syscalls: kevent, kevent64
/*!
* @function kevent_legacy_get_deadline
*
* @brief
* Compute the deadline for the legacy kevent syscalls.
*
* @discussion
* This is not necessary if KEVENT_FLAG_IMMEDIATE is specified,
* as this takes precedence over the deadline.
*
* This function will fail if utimeout is USER_ADDR_NULL
* (the caller should check).
*/
static int
kevent_legacy_get_deadline(int flags, user_addr_t utimeout, uint64_t *deadline)
{
struct timespec ts;
if (flags & KEVENT_FLAG_PROC64) {
struct user64_timespec ts64;
int error = copyin(utimeout, &ts64, sizeof(ts64));
if (__improbable(error)) {
return error;
}
ts.tv_sec = (unsigned long)ts64.tv_sec;
ts.tv_nsec = (long)ts64.tv_nsec;
} else {
struct user32_timespec ts32;
int error = copyin(utimeout, &ts32, sizeof(ts32));
if (__improbable(error)) {
return error;
}
ts.tv_sec = ts32.tv_sec;
ts.tv_nsec = ts32.tv_nsec;
}
if (!timespec_is_valid(&ts)) {
return EINVAL;
}
clock_absolutetime_interval_to_deadline(tstoabstime(&ts), deadline);
return 0;
}
/*!
* @function kevent_legacy_internal
*
* @brief
* The core implementation for kevent and kevent64
*/
OS_NOINLINE
static int
kevent_legacy_internal(struct proc *p, struct kevent64_args *uap,
int32_t *retval, int flags)
{
uthread_t uth = current_uthread();
kevent_ctx_t kectx = &uth->uu_save.uus_kevent;
struct kqueue *kq;
int error;
if (__improbable(uap->flags & KEVENT_ID_FLAG_USER)) {
return EINVAL;
}
flags = kevent_adjust_flags_for_proc(p, flags);
kectx->kec_data_out = 0;
kectx->kec_data_avail = 0;
kectx->kec_data_size = 0;
kectx->kec_data_resid = 0;
kectx->kec_deadline = 0;
kectx->kec_fp = NULL;
kectx->kec_fd = uap->fd;
/* the kec_process_* fields are filled if kqueue_scann is called only */
/* convert timeout to absolute - if we have one (and not immediate) */
if (__improbable(uap->timeout && !(flags & KEVENT_FLAG_IMMEDIATE))) {
error = kevent_legacy_get_deadline(flags, uap->timeout,
&kectx->kec_deadline);
if (__improbable(error)) {
return error;
}
}
/* get the kq we are going to be working on */
if (flags & KEVENT_FLAG_WORKQ) {
error = kevent_get_kqwq(p, flags, uap->nevents, &kq);
} else {
error = kevent_get_kqfile(p, uap->fd, flags, &kectx->kec_fp, &kq);
}
if (__improbable(error)) {
return error;
}
return kevent_internal(kq, uap->changelist, uap->nchanges,
uap->eventlist, uap->nevents, flags, kectx, retval,
/*legacy*/ true);
}
/*!
* @function kevent
*
* @brief
* The legacy kevent() syscall.
*/
int
kevent(struct proc *p, struct kevent_args *uap, int32_t *retval)
{
struct kevent64_args args = {
.fd = uap->fd,
.changelist = uap->changelist,
.nchanges = uap->nchanges,
.eventlist = uap->eventlist,
.nevents = uap->nevents,
.timeout = uap->timeout,
};
return kevent_legacy_internal(p, &args, retval, KEVENT_FLAG_LEGACY32);
}
/*!
* @function kevent64
*
* @brief
* The legacy kevent64() syscall.
*/
int
kevent64(struct proc *p, struct kevent64_args *uap, int32_t *retval)
{
int flags = (uap->flags & KEVENT_FLAG_USER) | KEVENT_FLAG_LEGACY64;
return kevent_legacy_internal(p, uap, retval, flags);
}
#pragma mark - socket interface
#if SOCKETS
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/protosw.h>
#include <sys/domain.h>
#include <sys/mbuf.h>
#include <sys/kern_event.h>
#include <sys/malloc.h>
#include <sys/sys_domain.h>
#include <sys/syslog.h>
#ifndef ROUNDUP64
#define ROUNDUP64(x) P2ROUNDUP((x), sizeof (u_int64_t))
#endif
#ifndef ADVANCE64
#define ADVANCE64(p, n) (void*)((char *)(p) + ROUNDUP64(n))
#endif
static LCK_GRP_DECLARE(kev_lck_grp, "Kernel Event Protocol");
static LCK_RW_DECLARE(kev_rwlock, &kev_lck_grp);
static int kev_attach(struct socket *so, int proto, struct proc *p);
static int kev_detach(struct socket *so);
static int kev_control(struct socket *so, u_long cmd, caddr_t data,
struct ifnet *ifp, struct proc *p);
static lck_mtx_t * event_getlock(struct socket *, int);
static int event_lock(struct socket *, int, void *);
static int event_unlock(struct socket *, int, void *);
static int event_sofreelastref(struct socket *);
static void kev_delete(struct kern_event_pcb *);
static struct pr_usrreqs event_usrreqs = {
.pru_attach = kev_attach,
.pru_control = kev_control,
.pru_detach = kev_detach,
.pru_soreceive = soreceive,
};
static struct protosw eventsw[] = {
{
.pr_type = SOCK_RAW,
.pr_protocol = SYSPROTO_EVENT,
.pr_flags = PR_ATOMIC,
.pr_usrreqs = &event_usrreqs,
.pr_lock = event_lock,
.pr_unlock = event_unlock,
.pr_getlock = event_getlock,
}
};
__private_extern__ int kevt_getstat SYSCTL_HANDLER_ARGS;
__private_extern__ int kevt_pcblist SYSCTL_HANDLER_ARGS;
SYSCTL_NODE(_net_systm, OID_AUTO, kevt,
CTLFLAG_RW | CTLFLAG_LOCKED, 0, "Kernel event family");
struct kevtstat kevtstat;
SYSCTL_PROC(_net_systm_kevt, OID_AUTO, stats,
CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
kevt_getstat, "S,kevtstat", "");
SYSCTL_PROC(_net_systm_kevt, OID_AUTO, pcblist,
CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0,
kevt_pcblist, "S,xkevtpcb", "");
static lck_mtx_t *
event_getlock(struct socket *so, int flags)
{
#pragma unused(flags)
struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb;
if (so->so_pcb != NULL) {
if (so->so_usecount < 0) {
panic("%s: so=%p usecount=%d lrh= %s", __func__,
so, so->so_usecount, solockhistory_nr(so));
}
/* NOTREACHED */
} else {
panic("%s: so=%p NULL NO so_pcb %s", __func__,
so, solockhistory_nr(so));
/* NOTREACHED */
}
return &ev_pcb->evp_mtx;
}
static int
event_lock(struct socket *so, int refcount, void *lr)
{
void *lr_saved;
if (lr == NULL) {
lr_saved = __builtin_return_address(0);
} else {
lr_saved = lr;
}
if (so->so_pcb != NULL) {
lck_mtx_lock(&((struct kern_event_pcb *)so->so_pcb)->evp_mtx);
} else {
panic("%s: so=%p NO PCB! lr=%p lrh= %s", __func__,
so, lr_saved, solockhistory_nr(so));
/* NOTREACHED */
}
if (so->so_usecount < 0) {
panic("%s: so=%p so_pcb=%p lr=%p ref=%d lrh= %s", __func__,
so, so->so_pcb, lr_saved, so->so_usecount,
solockhistory_nr(so));
/* NOTREACHED */
}
if (refcount) {
so->so_usecount++;
}
so->lock_lr[so->next_lock_lr] = lr_saved;
so->next_lock_lr = (so->next_lock_lr + 1) % SO_LCKDBG_MAX;
return 0;
}
static int
event_unlock(struct socket *so, int refcount, void *lr)
{
void *lr_saved;
lck_mtx_t *mutex_held;
if (lr == NULL) {
lr_saved = __builtin_return_address(0);
} else {
lr_saved = lr;
}
if (refcount) {
so->so_usecount--;
}
if (so->so_usecount < 0) {
panic("%s: so=%p usecount=%d lrh= %s", __func__,
so, so->so_usecount, solockhistory_nr(so));
/* NOTREACHED */
}
if (so->so_pcb == NULL) {
panic("%s: so=%p NO PCB usecount=%d lr=%p lrh= %s", __func__,
so, so->so_usecount, (void *)lr_saved,
solockhistory_nr(so));
/* NOTREACHED */
}
mutex_held = (&((struct kern_event_pcb *)so->so_pcb)->evp_mtx);
LCK_MTX_ASSERT(mutex_held, LCK_MTX_ASSERT_OWNED);
so->unlock_lr[so->next_unlock_lr] = lr_saved;
so->next_unlock_lr = (so->next_unlock_lr + 1) % SO_LCKDBG_MAX;
if (so->so_usecount == 0) {
VERIFY(so->so_flags & SOF_PCBCLEARING);
event_sofreelastref(so);
} else {
lck_mtx_unlock(mutex_held);
}
return 0;
}
static int
event_sofreelastref(struct socket *so)
{
struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *)so->so_pcb;
LCK_MTX_ASSERT(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_OWNED);
so->so_pcb = NULL;
/*
* Disable upcall in the event another thread is in kev_post_msg()
* appending record to the receive socket buffer, since sbwakeup()
* may release the socket lock otherwise.
*/
so->so_rcv.sb_flags &= ~SB_UPCALL;
so->so_snd.sb_flags &= ~SB_UPCALL;
so->so_event = sonullevent;
lck_mtx_unlock(&(ev_pcb->evp_mtx));
LCK_MTX_ASSERT(&(ev_pcb->evp_mtx), LCK_MTX_ASSERT_NOTOWNED);
lck_rw_lock_exclusive(&kev_rwlock);
LIST_REMOVE(ev_pcb, evp_link);
kevtstat.kes_pcbcount--;
kevtstat.kes_gencnt++;
lck_rw_done(&kev_rwlock);
kev_delete(ev_pcb);
sofreelastref(so, 1);
return 0;
}
static int event_proto_count = (sizeof(eventsw) / sizeof(struct protosw));
static
struct kern_event_head kern_event_head;
static u_int32_t static_event_id = 0;
static KALLOC_TYPE_DEFINE(ev_pcb_zone, struct kern_event_pcb, NET_KT_DEFAULT);
/*
* Install the protosw's for the NKE manager. Invoked at extension load time
*/
void
kern_event_init(struct domain *dp)
{
struct protosw *pr;
int i;
VERIFY(!(dp->dom_flags & DOM_INITIALIZED));
VERIFY(dp == systemdomain);
for (i = 0, pr = &eventsw[0]; i < event_proto_count; i++, pr++) {
net_add_proto(pr, dp, 1);
}
}
static int
kev_attach(struct socket *so, __unused int proto, __unused struct proc *p)
{
int error = 0;
struct kern_event_pcb *ev_pcb;
error = soreserve(so, KEV_SNDSPACE, KEV_RECVSPACE);
if (error != 0) {
return error;
}
ev_pcb = zalloc_flags(ev_pcb_zone, Z_WAITOK | Z_ZERO);
lck_mtx_init(&ev_pcb->evp_mtx, &kev_lck_grp, LCK_ATTR_NULL);
ev_pcb->evp_socket = so;
ev_pcb->evp_vendor_code_filter = 0xffffffff;
so->so_pcb = (caddr_t) ev_pcb;
lck_rw_lock_exclusive(&kev_rwlock);
LIST_INSERT_HEAD(&kern_event_head, ev_pcb, evp_link);
kevtstat.kes_pcbcount++;
kevtstat.kes_gencnt++;
lck_rw_done(&kev_rwlock);
return error;
}
static void
kev_delete(struct kern_event_pcb *ev_pcb)
{
VERIFY(ev_pcb != NULL);
lck_mtx_destroy(&ev_pcb->evp_mtx, &kev_lck_grp);
zfree(ev_pcb_zone, ev_pcb);
}
static int
kev_detach(struct socket *so)
{
struct kern_event_pcb *ev_pcb = (struct kern_event_pcb *) so->so_pcb;
if (ev_pcb != NULL) {
soisdisconnected(so);
so->so_flags |= SOF_PCBCLEARING;
}
return 0;
}
/*
* For now, kev_vendor_code and mbuf_tags use the same
* mechanism.
*/
errno_t
kev_vendor_code_find(
const char *string,
u_int32_t *out_vendor_code)
{
if (strlen(string) >= KEV_VENDOR_CODE_MAX_STR_LEN) {
return EINVAL;
}
return net_str_id_find_internal(string, out_vendor_code,
NSI_VENDOR_CODE, 1);
}
errno_t
kev_msg_post(struct kev_msg *event_msg)
{
mbuf_tag_id_t min_vendor, max_vendor;
net_str_id_first_last(&min_vendor, &max_vendor, NSI_VENDOR_CODE);
if (event_msg == NULL) {
return EINVAL;
}
/*
* Limit third parties to posting events for registered vendor codes
* only
*/
if (event_msg->vendor_code < min_vendor ||
event_msg->vendor_code > max_vendor) {
os_atomic_inc(&kevtstat.kes_badvendor, relaxed);
return EINVAL;
}
return kev_post_msg(event_msg);
}
static int
kev_post_msg_internal(struct kev_msg *event_msg, int wait)
{
struct mbuf *m, *m2;
struct kern_event_pcb *ev_pcb;
struct kern_event_msg *ev;
char *tmp;
u_int32_t total_size;
int i;
#if SKYWALK && defined(XNU_TARGET_OS_OSX)
/*
* Special hook for ALF state updates
*/
if (event_msg->vendor_code == KEV_VENDOR_APPLE &&
event_msg->kev_class == KEV_NKE_CLASS &&
event_msg->kev_subclass == KEV_NKE_ALF_SUBCLASS &&
event_msg->event_code == KEV_NKE_ALF_STATE_CHANGED) {
#if (DEBUG || DEVELOPMENT)
os_log_info(OS_LOG_DEFAULT, "KEV_NKE_ALF_STATE_CHANGED posted");
#endif /* DEBUG || DEVELOPMENT */
net_filter_event_mark(NET_FILTER_EVENT_ALF,
net_check_compatible_alf());
}
#endif /* SKYWALK && XNU_TARGET_OS_OSX */
/* Verify the message is small enough to fit in one mbuf w/o cluster */
total_size = KEV_MSG_HEADER_SIZE;
for (i = 0; i < 5; i++) {
if (event_msg->dv[i].data_length == 0) {
break;
}
total_size += event_msg->dv[i].data_length;
}
if (total_size > MLEN) {
os_atomic_inc(&kevtstat.kes_toobig, relaxed);
return EMSGSIZE;
}
m = m_get(wait, MT_DATA);
if (m == 0) {
os_atomic_inc(&kevtstat.kes_nomem, relaxed);
return ENOMEM;
}
ev = mtod(m, struct kern_event_msg *);
total_size = KEV_MSG_HEADER_SIZE;
tmp = (char *) &ev->event_data[0];
for (i = 0; i < 5; i++) {
if (event_msg->dv[i].data_length == 0) {
break;
}
total_size += event_msg->dv[i].data_length;
bcopy(event_msg->dv[i].data_ptr, tmp,
event_msg->dv[i].data_length);
tmp += event_msg->dv[i].data_length;
}
ev->id = ++static_event_id;
ev->total_size = total_size;
ev->vendor_code = event_msg->vendor_code;
ev->kev_class = event_msg->kev_class;
ev->kev_subclass = event_msg->kev_subclass;
ev->event_code = event_msg->event_code;
m->m_len = total_size;
lck_rw_lock_shared(&kev_rwlock);
for (ev_pcb = LIST_FIRST(&kern_event_head);
ev_pcb;
ev_pcb = LIST_NEXT(ev_pcb, evp_link)) {
lck_mtx_lock(&ev_pcb->evp_mtx);
if (ev_pcb->evp_socket->so_pcb == NULL) {
lck_mtx_unlock(&ev_pcb->evp_mtx);
continue;
}
if (ev_pcb->evp_vendor_code_filter != KEV_ANY_VENDOR) {
if (ev_pcb->evp_vendor_code_filter != ev->vendor_code) {
lck_mtx_unlock(&ev_pcb->evp_mtx);
continue;
}
if (ev_pcb->evp_class_filter != KEV_ANY_CLASS) {
if (ev_pcb->evp_class_filter != ev->kev_class) {
lck_mtx_unlock(&ev_pcb->evp_mtx);
continue;
}
if ((ev_pcb->evp_subclass_filter !=
KEV_ANY_SUBCLASS) &&
(ev_pcb->evp_subclass_filter !=
ev->kev_subclass)) {
lck_mtx_unlock(&ev_pcb->evp_mtx);
continue;
}
}
}
m2 = m_copym(m, 0, m->m_len, wait);
if (m2 == 0) {
os_atomic_inc(&kevtstat.kes_nomem, relaxed);
m_free(m);
lck_mtx_unlock(&ev_pcb->evp_mtx);
lck_rw_done(&kev_rwlock);
return ENOMEM;
}
if (sbappendrecord(&ev_pcb->evp_socket->so_rcv, m2)) {
/*
* We use "m" for the socket stats as it would be
* unsafe to use "m2"
*/
so_inc_recv_data_stat(ev_pcb->evp_socket,
1, m->m_len, MBUF_TC_BE);
sorwakeup(ev_pcb->evp_socket);
os_atomic_inc(&kevtstat.kes_posted, relaxed);
} else {
os_atomic_inc(&kevtstat.kes_fullsock, relaxed);
}
lck_mtx_unlock(&ev_pcb->evp_mtx);
}
m_free(m);
lck_rw_done(&kev_rwlock);
return 0;
}
int
kev_post_msg(struct kev_msg *event_msg)
{
return kev_post_msg_internal(event_msg, M_WAIT);
}
int
kev_post_msg_nowait(struct kev_msg *event_msg)
{
return kev_post_msg_internal(event_msg, M_NOWAIT);
}
static int
kev_control(struct socket *so,
u_long cmd,
caddr_t data,
__unused struct ifnet *ifp,
__unused struct proc *p)
{
struct kev_request *kev_req = (struct kev_request *) data;
struct kern_event_pcb *ev_pcb;
struct kev_vendor_code *kev_vendor;
u_int32_t *id_value = (u_int32_t *) data;
switch (cmd) {
case SIOCGKEVID:
*id_value = static_event_id;
break;
case SIOCSKEVFILT:
ev_pcb = (struct kern_event_pcb *) so->so_pcb;
ev_pcb->evp_vendor_code_filter = kev_req->vendor_code;
ev_pcb->evp_class_filter = kev_req->kev_class;
ev_pcb->evp_subclass_filter = kev_req->kev_subclass;
break;
case SIOCGKEVFILT:
ev_pcb = (struct kern_event_pcb *) so->so_pcb;
kev_req->vendor_code = ev_pcb->evp_vendor_code_filter;
kev_req->kev_class = ev_pcb->evp_class_filter;
kev_req->kev_subclass = ev_pcb->evp_subclass_filter;
break;
case SIOCGKEVVENDOR:
kev_vendor = (struct kev_vendor_code *)data;
/* Make sure string is NULL terminated */
kev_vendor->vendor_string[KEV_VENDOR_CODE_MAX_STR_LEN - 1] = 0;
return net_str_id_find_internal(kev_vendor->vendor_string,
&kev_vendor->vendor_code, NSI_VENDOR_CODE, 0);
default:
return ENOTSUP;
}
return 0;
}
int
kevt_getstat SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
int error = 0;
lck_rw_lock_shared(&kev_rwlock);
if (req->newptr != USER_ADDR_NULL) {
error = EPERM;
goto done;
}
if (req->oldptr == USER_ADDR_NULL) {
req->oldidx = sizeof(struct kevtstat);
goto done;
}
error = SYSCTL_OUT(req, &kevtstat,
MIN(sizeof(struct kevtstat), req->oldlen));
done:
lck_rw_done(&kev_rwlock);
return error;
}
__private_extern__ int
kevt_pcblist SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg1, arg2)
int error = 0;
uint64_t n, i;
struct xsystmgen xsg;
void *buf = NULL;
size_t item_size = ROUNDUP64(sizeof(struct xkevtpcb)) +
ROUNDUP64(sizeof(struct xsocket_n)) +
2 * ROUNDUP64(sizeof(struct xsockbuf_n)) +
ROUNDUP64(sizeof(struct xsockstat_n));
struct kern_event_pcb *ev_pcb;
buf = kalloc_data(item_size, Z_WAITOK | Z_ZERO);
if (buf == NULL) {
return ENOMEM;
}
lck_rw_lock_shared(&kev_rwlock);
n = kevtstat.kes_pcbcount;
if (req->oldptr == USER_ADDR_NULL) {
req->oldidx = (size_t) ((n + n / 8) * item_size);
goto done;
}
if (req->newptr != USER_ADDR_NULL) {
error = EPERM;
goto done;
}
bzero(&xsg, sizeof(xsg));
xsg.xg_len = sizeof(xsg);
xsg.xg_count = n;
xsg.xg_gen = kevtstat.kes_gencnt;
xsg.xg_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xsg, sizeof(xsg));
if (error) {
goto done;
}
/*
* We are done if there is no pcb
*/
if (n == 0) {
goto done;
}
i = 0;
for (i = 0, ev_pcb = LIST_FIRST(&kern_event_head);
i < n && ev_pcb != NULL;
i++, ev_pcb = LIST_NEXT(ev_pcb, evp_link)) {
struct xkevtpcb *xk = (struct xkevtpcb *)buf;
struct xsocket_n *xso = (struct xsocket_n *)
ADVANCE64(xk, sizeof(*xk));
struct xsockbuf_n *xsbrcv = (struct xsockbuf_n *)
ADVANCE64(xso, sizeof(*xso));
struct xsockbuf_n *xsbsnd = (struct xsockbuf_n *)
ADVANCE64(xsbrcv, sizeof(*xsbrcv));
struct xsockstat_n *xsostats = (struct xsockstat_n *)
ADVANCE64(xsbsnd, sizeof(*xsbsnd));
bzero(buf, item_size);
lck_mtx_lock(&ev_pcb->evp_mtx);
xk->kep_len = sizeof(struct xkevtpcb);
xk->kep_kind = XSO_EVT;
xk->kep_evtpcb = (uint64_t)VM_KERNEL_ADDRPERM(ev_pcb);
xk->kep_vendor_code_filter = ev_pcb->evp_vendor_code_filter;
xk->kep_class_filter = ev_pcb->evp_class_filter;
xk->kep_subclass_filter = ev_pcb->evp_subclass_filter;
sotoxsocket_n(ev_pcb->evp_socket, xso);
sbtoxsockbuf_n(ev_pcb->evp_socket ?
&ev_pcb->evp_socket->so_rcv : NULL, xsbrcv);
sbtoxsockbuf_n(ev_pcb->evp_socket ?
&ev_pcb->evp_socket->so_snd : NULL, xsbsnd);
sbtoxsockstat_n(ev_pcb->evp_socket, xsostats);
lck_mtx_unlock(&ev_pcb->evp_mtx);
error = SYSCTL_OUT(req, buf, item_size);
}
if (error == 0) {
/*
* Give the user an updated idea of our state.
* If the generation differs from what we told
* her before, she knows that something happened
* while we were processing this request, and it
* might be necessary to retry.
*/
bzero(&xsg, sizeof(xsg));
xsg.xg_len = sizeof(xsg);
xsg.xg_count = n;
xsg.xg_gen = kevtstat.kes_gencnt;
xsg.xg_sogen = so_gencnt;
error = SYSCTL_OUT(req, &xsg, sizeof(xsg));
if (error) {
goto done;
}
}
done:
lck_rw_done(&kev_rwlock);
kfree_data(buf, item_size);
return error;
}
#endif /* SOCKETS */
int
fill_kqueueinfo(kqueue_t kqu, struct kqueue_info * kinfo)
{
struct vinfo_stat * st;
st = &kinfo->kq_stat;
st->vst_size = kqu.kq->kq_count;
if (kqu.kq->kq_state & KQ_KEV_QOS) {
st->vst_blksize = sizeof(struct kevent_qos_s);
} else if (kqu.kq->kq_state & KQ_KEV64) {
st->vst_blksize = sizeof(struct kevent64_s);
} else {
st->vst_blksize = sizeof(struct kevent);
}
st->vst_mode = S_IFIFO;
st->vst_ino = (kqu.kq->kq_state & KQ_DYNAMIC) ?
kqu.kqwl->kqwl_dynamicid : 0;
/* flags exported to libproc as PROC_KQUEUE_* (sys/proc_info.h) */
#define PROC_KQUEUE_MASK (KQ_SLEEP|KQ_KEV32|KQ_KEV64|KQ_KEV_QOS|KQ_WORKQ|KQ_WORKLOOP)
static_assert(PROC_KQUEUE_SLEEP == KQ_SLEEP);
static_assert(PROC_KQUEUE_32 == KQ_KEV32);
static_assert(PROC_KQUEUE_64 == KQ_KEV64);
static_assert(PROC_KQUEUE_QOS == KQ_KEV_QOS);
static_assert(PROC_KQUEUE_WORKQ == KQ_WORKQ);
static_assert(PROC_KQUEUE_WORKLOOP == KQ_WORKLOOP);
kinfo->kq_state = kqu.kq->kq_state & PROC_KQUEUE_MASK;
if ((kqu.kq->kq_state & (KQ_WORKLOOP | KQ_WORKQ)) == 0) {
if (kqu.kqf->kqf_sel.si_flags & SI_RECORDED) {
kinfo->kq_state |= PROC_KQUEUE_SELECT;
}
}
return 0;
}
static int
fill_kqueue_dyninfo(struct kqworkloop *kqwl, struct kqueue_dyninfo *kqdi)
{
workq_threadreq_t kqr = &kqwl->kqwl_request;
workq_threadreq_param_t trp = {};
int err;
if ((kqwl->kqwl_state & KQ_WORKLOOP) == 0) {
return EINVAL;
}
if ((err = fill_kqueueinfo(&kqwl->kqwl_kqueue, &kqdi->kqdi_info))) {
return err;
}
kqlock(kqwl);
kqdi->kqdi_servicer = thread_tid(kqr_thread(kqr));
kqdi->kqdi_owner = thread_tid(kqwl->kqwl_owner);
kqdi->kqdi_request_state = kqr->tr_state;
kqdi->kqdi_async_qos = kqr->tr_kq_qos_index;
kqdi->kqdi_events_qos = kqr->tr_kq_override_index;
kqdi->kqdi_sync_waiters = 0;
kqdi->kqdi_sync_waiter_qos = 0;
trp.trp_value = kqwl->kqwl_params;
if (trp.trp_flags & TRP_PRIORITY) {
kqdi->kqdi_pri = trp.trp_pri;
} else {
kqdi->kqdi_pri = 0;
}
if (trp.trp_flags & TRP_POLICY) {
kqdi->kqdi_pol = trp.trp_pol;
} else {
kqdi->kqdi_pol = 0;
}
if (trp.trp_flags & TRP_CPUPERCENT) {
kqdi->kqdi_cpupercent = trp.trp_cpupercent;
} else {
kqdi->kqdi_cpupercent = 0;
}
kqunlock(kqwl);
return 0;
}
static unsigned long
kevent_extinfo_emit(struct kqueue *kq, struct knote *kn, struct kevent_extinfo *buf,
unsigned long buflen, unsigned long nknotes)
{
for (; kn; kn = SLIST_NEXT(kn, kn_link)) {
if (kq == knote_get_kq(kn)) {
if (nknotes < buflen) {
struct kevent_extinfo *info = &buf[nknotes];
kqlock(kq);
if (knote_fops(kn)->f_sanitized_copyout) {
knote_fops(kn)->f_sanitized_copyout(kn, &info->kqext_kev);
} else {
info->kqext_kev = *(struct kevent_qos_s *)&kn->kn_kevent;
}
if (knote_has_qos(kn)) {
info->kqext_kev.qos =
_pthread_priority_thread_qos_fast(kn->kn_qos);
} else {
info->kqext_kev.qos = kn->kn_qos_override;
}
info->kqext_kev.filter |= 0xff00; /* sign extend filter */
info->kqext_kev.xflags = 0; /* this is where sfflags lives */
info->kqext_kev.data = 0; /* this is where sdata lives */
info->kqext_sdata = kn->kn_sdata;
info->kqext_status = kn->kn_status;
info->kqext_sfflags = kn->kn_sfflags;
kqunlock(kq);
}
/* we return total number of knotes, which may be more than requested */
nknotes++;
}
}
return nknotes;
}
int
kevent_copyout_proc_dynkqids(void *proc, user_addr_t ubuf, uint32_t ubufsize,
int32_t *nkqueues_out)
{
proc_t p = (proc_t)proc;
struct filedesc *fdp = &p->p_fd;
unsigned int nkqueues = 0;
unsigned long ubuflen = ubufsize / sizeof(kqueue_id_t);
size_t buflen, bufsize;
kqueue_id_t *kq_ids = NULL;
int err = 0;
assert(p != NULL);
if (ubuf == USER_ADDR_NULL && ubufsize != 0) {
err = EINVAL;
goto out;
}
buflen = MIN(ubuflen, PROC_PIDDYNKQUEUES_MAX);
if (ubuflen != 0) {
if (os_mul_overflow(sizeof(kqueue_id_t), buflen, &bufsize)) {
err = ERANGE;
goto out;
}
kq_ids = (kqueue_id_t *)kalloc_data(bufsize, Z_WAITOK | Z_ZERO);
if (!kq_ids) {
err = ENOMEM;
goto out;
}
}
kqhash_lock(fdp);
u_long kqhashmask = fdp->fd_kqhashmask;
if (kqhashmask > 0) {
for (uint32_t i = 0; i < kqhashmask + 1; i++) {
struct kqworkloop *kqwl;
LIST_FOREACH(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink) {
/* report the number of kqueues, even if they don't all fit */
if (nkqueues < buflen) {
kq_ids[nkqueues] = kqwl->kqwl_dynamicid;
}
nkqueues++;
}
/*
* Drop the kqhash lock and take it again to give some breathing room
*/
kqhash_unlock(fdp);
kqhash_lock(fdp);
/*
* Reevaluate to see if we have raced with someone who changed this -
* if we have, we should bail out with the set of info captured so far
*/
if (fdp->fd_kqhashmask != kqhashmask) {
break;
}
}
}
kqhash_unlock(fdp);
if (kq_ids) {
size_t copysize;
if (os_mul_overflow(sizeof(kqueue_id_t), MIN(buflen, nkqueues), &copysize)) {
err = ERANGE;
goto out;
}
assert(ubufsize >= copysize);
err = copyout(kq_ids, ubuf, copysize);
}
out:
if (kq_ids) {
kfree_data(kq_ids, bufsize);
}
if (!err) {
*nkqueues_out = (int)min(nkqueues, PROC_PIDDYNKQUEUES_MAX);
}
return err;
}
int
kevent_copyout_dynkqinfo(void *proc, kqueue_id_t kq_id, user_addr_t ubuf,
uint32_t ubufsize, int32_t *size_out)
{
proc_t p = (proc_t)proc;
struct kqworkloop *kqwl;
int err = 0;
struct kqueue_dyninfo kqdi = { };
assert(p != NULL);
if (ubufsize < sizeof(struct kqueue_info)) {
return ENOBUFS;
}
kqwl = kqworkloop_hash_lookup_and_retain(&p->p_fd, kq_id);
if (!kqwl) {
return ESRCH;
}
/*
* backward compatibility: allow the argument to this call to only be
* a struct kqueue_info
*/
if (ubufsize >= sizeof(struct kqueue_dyninfo)) {
ubufsize = sizeof(struct kqueue_dyninfo);
err = fill_kqueue_dyninfo(kqwl, &kqdi);
} else {
ubufsize = sizeof(struct kqueue_info);
err = fill_kqueueinfo(&kqwl->kqwl_kqueue, &kqdi.kqdi_info);
}
if (err == 0 && (err = copyout(&kqdi, ubuf, ubufsize)) == 0) {
*size_out = ubufsize;
}
kqworkloop_release(kqwl);
return err;
}
int
kevent_copyout_dynkqextinfo(void *proc, kqueue_id_t kq_id, user_addr_t ubuf,
uint32_t ubufsize, int32_t *nknotes_out)
{
proc_t p = (proc_t)proc;
struct kqworkloop *kqwl;
int err;
kqwl = kqworkloop_hash_lookup_and_retain(&p->p_fd, kq_id);
if (!kqwl) {
return ESRCH;
}
err = pid_kqueue_extinfo(p, &kqwl->kqwl_kqueue, ubuf, ubufsize, nknotes_out);
kqworkloop_release(kqwl);
return err;
}
int
pid_kqueue_extinfo(proc_t p, struct kqueue *kq, user_addr_t ubuf,
uint32_t bufsize, int32_t *retval)
{
struct knote *kn;
int i;
int err = 0;
struct filedesc *fdp = &p->p_fd;
unsigned long nknotes = 0;
unsigned long buflen = bufsize / sizeof(struct kevent_extinfo);
struct kevent_extinfo *kqext = NULL;
/* arbitrary upper limit to cap kernel memory usage, copyout size, etc. */
buflen = MIN(buflen, PROC_PIDFDKQUEUE_KNOTES_MAX);
kqext = (struct kevent_extinfo *)kalloc_data(buflen * sizeof(struct kevent_extinfo), Z_WAITOK | Z_ZERO);
if (kqext == NULL) {
err = ENOMEM;
goto out;
}
proc_fdlock(p);
u_long fd_knlistsize = fdp->fd_knlistsize;
struct klist *fd_knlist = fdp->fd_knlist;
for (i = 0; i < fd_knlistsize; i++) {
kn = SLIST_FIRST(&fd_knlist[i]);
nknotes = kevent_extinfo_emit(kq, kn, kqext, buflen, nknotes);
proc_fdunlock(p);
proc_fdlock(p);
/*
* Reevaluate to see if we have raced with someone who changed this -
* if we have, we return the set of info for fd_knlistsize we knew
* in the beginning except if knotes_dealloc interleaves with us.
* In that case, we bail out early with the set of info captured so far.
*/
if (fd_knlistsize != fdp->fd_knlistsize) {
if (fdp->fd_knlistsize) {
/* kq_add_knote might grow fdp->fd_knlist. */
fd_knlist = fdp->fd_knlist;
} else {
break;
}
}
}
proc_fdunlock(p);
knhash_lock(fdp);
u_long knhashmask = fdp->fd_knhashmask;
if (knhashmask != 0) {
for (i = 0; i < (int)knhashmask + 1; i++) {
kn = SLIST_FIRST(&fdp->fd_knhash[i]);
nknotes = kevent_extinfo_emit(kq, kn, kqext, buflen, nknotes);
knhash_unlock(fdp);
knhash_lock(fdp);
/*
* Reevaluate to see if we have raced with someone who changed this -
* if we have, we should bail out with the set of info captured so far
*/
if (fdp->fd_knhashmask != knhashmask) {
break;
}
}
}
knhash_unlock(fdp);
assert(bufsize >= sizeof(struct kevent_extinfo) * MIN(buflen, nknotes));
err = copyout(kqext, ubuf, sizeof(struct kevent_extinfo) * MIN(buflen, nknotes));
out:
kfree_data(kqext, buflen * sizeof(struct kevent_extinfo));
if (!err) {
*retval = (int32_t)MIN(nknotes, PROC_PIDFDKQUEUE_KNOTES_MAX);
}
return err;
}
static unsigned int
klist_copy_udata(struct klist *list, uint64_t *buf,
unsigned int buflen, unsigned int nknotes)
{
struct knote *kn;
SLIST_FOREACH(kn, list, kn_link) {
if (nknotes < buflen) {
/*
* kevent_register will always set kn_udata atomically
* so that we don't have to take any kqlock here.
*/
buf[nknotes] = os_atomic_load_wide(&kn->kn_udata, relaxed);
}
/* we return total number of knotes, which may be more than requested */
nknotes++;
}
return nknotes;
}
int
kevent_proc_copy_uptrs(void *proc, uint64_t *buf, uint32_t bufsize)
{
proc_t p = (proc_t)proc;
struct filedesc *fdp = &p->p_fd;
unsigned int nuptrs = 0;
unsigned int buflen = bufsize / sizeof(uint64_t);
struct kqworkloop *kqwl;
u_long size = 0;
struct klist *fd_knlist = NULL;
if (buflen > 0) {
assert(buf != NULL);
}
/*
* Copyout the uptrs as much as possible but make sure to drop the respective
* locks and take them again periodically so that we don't blow through
* preemption disabled timeouts. Always reevaluate to see if we have raced
* with someone who changed size of the hash - if we have, we return info for
* the size of the hash we knew in the beginning except if it drops to 0.
* In that case, we bail out with the set of info captured so far
*/
proc_fdlock(p);
size = fdp->fd_knlistsize;
fd_knlist = fdp->fd_knlist;
for (int i = 0; i < size; i++) {
nuptrs = klist_copy_udata(&fd_knlist[i], buf, buflen, nuptrs);
proc_fdunlock(p);
proc_fdlock(p);
if (size != fdp->fd_knlistsize) {
if (fdp->fd_knlistsize) {
/* kq_add_knote might grow fdp->fd_knlist. */
fd_knlist = fdp->fd_knlist;
} else {
break;
}
}
}
proc_fdunlock(p);
knhash_lock(fdp);
size = fdp->fd_knhashmask;
if (size != 0) {
for (size_t i = 0; i < size + 1; i++) {
nuptrs = klist_copy_udata(&fdp->fd_knhash[i], buf, buflen, nuptrs);
knhash_unlock(fdp);
knhash_lock(fdp);
/* The only path that can interleave with us today is knotes_dealloc. */
if (size != fdp->fd_knhashmask) {
break;
}
}
}
knhash_unlock(fdp);
kqhash_lock(fdp);
size = fdp->fd_kqhashmask;
if (size != 0) {
for (size_t i = 0; i < size + 1; i++) {
LIST_FOREACH(kqwl, &fdp->fd_kqhash[i], kqwl_hashlink) {
if (nuptrs < buflen) {
buf[nuptrs] = kqwl->kqwl_dynamicid;
}
nuptrs++;
}
kqhash_unlock(fdp);
kqhash_lock(fdp);
if (size != fdp->fd_kqhashmask) {
break;
}
}
}
kqhash_unlock(fdp);
return (int)nuptrs;
}
static void
kevent_set_return_to_kernel_user_tsd(proc_t p, thread_t thread)
{
uint64_t ast_addr;
bool proc_is_64bit = !!(p->p_flag & P_LP64);
size_t user_addr_size = proc_is_64bit ? 8 : 4;
uint32_t ast_flags32 = 0;
uint64_t ast_flags64 = 0;
struct uthread *ut = get_bsdthread_info(thread);
if (ut->uu_kqr_bound != NULL) {
ast_flags64 |= R2K_WORKLOOP_PENDING_EVENTS;
}
if (ast_flags64 == 0) {
return;
}
if (!(p->p_flag & P_LP64)) {
ast_flags32 = (uint32_t)ast_flags64;
assert(ast_flags64 < 0x100000000ull);
}
ast_addr = thread_rettokern_addr(thread);
if (ast_addr == 0) {
return;
}
if (copyout((proc_is_64bit ? (void *)&ast_flags64 : (void *)&ast_flags32),
(user_addr_t)ast_addr,
user_addr_size) != 0) {
printf("pid %d (tid:%llu): copyout of return_to_kernel ast flags failed with "
"ast_addr = %llu\n", proc_getpid(p), thread_tid(current_thread()), ast_addr);
}
}
/*
* Semantics of writing to TSD value:
*
* 1. It is written to by the kernel and cleared by userspace.
* 2. When the userspace code clears the TSD field, it takes responsibility for
* taking action on the quantum expiry action conveyed by kernel.
* 3. The TSD value is always cleared upon entry into userspace and upon exit of
* userspace back to kernel to make sure that it is never leaked across thread
* requests.
*/
void
kevent_set_workq_quantum_expiry_user_tsd(proc_t p, thread_t thread,
uint64_t flags)
{
uint64_t ast_addr;
bool proc_is_64bit = !!(p->p_flag & P_LP64);
uint32_t ast_flags32 = 0;
uint64_t ast_flags64 = flags;
if (ast_flags64 == 0) {
return;
}
if (!(p->p_flag & P_LP64)) {
ast_flags32 = (uint32_t)ast_flags64;
assert(ast_flags64 < 0x100000000ull);
}
ast_addr = thread_wqquantum_addr(thread);
assert(ast_addr != 0);
if (proc_is_64bit) {
if (copyout_atomic64(ast_flags64, (user_addr_t) ast_addr)) {
#if DEBUG || DEVELOPMENT
printf("pid %d (tid:%llu): copyout of workq quantum ast flags failed with "
"ast_addr = %llu\n", proc_getpid(p), thread_tid(thread), ast_addr);
#endif
}
} else {
if (copyout_atomic32(ast_flags32, (user_addr_t) ast_addr)) {
#if DEBUG || DEVELOPMENT
printf("pid %d (tid:%llu): copyout of workq quantum ast flags failed with "
"ast_addr = %llu\n", proc_getpid(p), thread_tid(thread), ast_addr);
#endif
}
}
}
void
kevent_ast(thread_t thread, uint16_t bits)
{
proc_t p = current_proc();
if (bits & AST_KEVENT_REDRIVE_THREADREQ) {
workq_kern_threadreq_redrive(p, WORKQ_THREADREQ_CAN_CREATE_THREADS);
}
if (bits & AST_KEVENT_RETURN_TO_KERNEL) {
kevent_set_return_to_kernel_user_tsd(p, thread);
}
if (bits & AST_KEVENT_WORKQ_QUANTUM_EXPIRED) {
workq_kern_quantum_expiry_reevaluate(p, thread);
}
}
#if DEVELOPMENT || DEBUG
#define KEVENT_SYSCTL_BOUND_ID 1
static int
kevent_sysctl SYSCTL_HANDLER_ARGS
{
#pragma unused(oidp, arg2)
uintptr_t type = (uintptr_t)arg1;
uint64_t bound_id = 0;
if (type != KEVENT_SYSCTL_BOUND_ID) {
return EINVAL;
}
if (req->newptr) {
return EINVAL;
}
struct uthread *ut = current_uthread();
if (!ut) {
return EFAULT;
}
workq_threadreq_t kqr = ut->uu_kqr_bound;
if (kqr) {
if (kqr->tr_flags & WORKQ_TR_FLAG_WORKLOOP) {
bound_id = kqr_kqworkloop(kqr)->kqwl_dynamicid;
} else {
bound_id = -1;
}
}
return sysctl_io_number(req, bound_id, sizeof(bound_id), NULL, NULL);
}
SYSCTL_NODE(_kern, OID_AUTO, kevent, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
"kevent information");
SYSCTL_PROC(_kern_kevent, OID_AUTO, bound_id,
CTLTYPE_QUAD | CTLFLAG_RD | CTLFLAG_LOCKED | CTLFLAG_MASKED,
(void *)KEVENT_SYSCTL_BOUND_ID,
sizeof(kqueue_id_t), kevent_sysctl, "Q",
"get the ID of the bound kqueue");
#endif /* DEVELOPMENT || DEBUG */
Reference in a new issue Copy permalink