kern_event.c revision 258324
1226048Sobrien/*- 268349Sobrien * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3267843Sdelphij * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 468349Sobrien * Copyright (c) 2009 Apple, Inc. 568349Sobrien * All rights reserved. 668349Sobrien * 7226048Sobrien * Redistribution and use in source and binary forms, with or without 8186690Sobrien * modification, are permitted provided that the following conditions 9226048Sobrien * are met: 10226048Sobrien * 1. Redistributions of source code must retain the above copyright 11226048Sobrien * notice, this list of conditions and the following disclaimer. 12226048Sobrien * 2. Redistributions in binary form must reproduce the above copyright 13226048Sobrien * notice, this list of conditions and the following disclaimer in the 14226048Sobrien * documentation and/or other materials provided with the distribution. 1568349Sobrien * 1668349Sobrien * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 1768349Sobrien * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 1868349Sobrien * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19186690Sobrien * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20133359Sobrien * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21133359Sobrien * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22133359Sobrien * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23133359Sobrien * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24133359Sobrien * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25226048Sobrien * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26226048Sobrien * SUCH DAMAGE. 27226048Sobrien */ 28226048Sobrien 29226048Sobrien#include <sys/cdefs.h> 30226048Sobrien__FBSDID("$FreeBSD: stable/10/sys/kern/kern_event.c 258324 2013-11-18 22:37:01Z pjd $"); 31226048Sobrien 32226048Sobrien#include "opt_ktrace.h" 33226048Sobrien 34267843Sdelphij#include <sys/param.h> 35226048Sobrien#include <sys/systm.h> 36226048Sobrien#include <sys/capability.h> 37267843Sdelphij#include <sys/kernel.h> 38267843Sdelphij#include <sys/lock.h> 39267843Sdelphij#include <sys/mutex.h> 40267843Sdelphij#include <sys/rwlock.h> 41267843Sdelphij#include <sys/proc.h> 42267843Sdelphij#include <sys/malloc.h> 43267843Sdelphij#include <sys/unistd.h> 44267843Sdelphij#include <sys/file.h> 4568349Sobrien#include <sys/filedesc.h> 46#include <sys/filio.h> 47#include <sys/fcntl.h> 48#include <sys/kthread.h> 49#include <sys/selinfo.h> 50#include <sys/stdatomic.h> 51#include <sys/queue.h> 52#include <sys/event.h> 53#include <sys/eventvar.h> 54#include <sys/poll.h> 55#include <sys/protosw.h> 56#include <sys/sigio.h> 57#include <sys/signalvar.h> 58#include <sys/socket.h> 59#include <sys/socketvar.h> 60#include <sys/stat.h> 61#include <sys/sysctl.h> 62#include <sys/sysproto.h> 63#include <sys/syscallsubr.h> 64#include <sys/taskqueue.h> 65#include <sys/uio.h> 66#ifdef KTRACE 67#include <sys/ktrace.h> 68#endif 69 70#include <vm/uma.h> 71 72static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 73 74/* 75 * This lock is used if multiple kq locks are required. This possibly 76 * should be made into a per proc lock. 77 */ 78static struct mtx kq_global; 79MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 80#define KQ_GLOBAL_LOCK(lck, haslck) do { \ 81 if (!haslck) \ 82 mtx_lock(lck); \ 83 haslck = 1; \ 84} while (0) 85#define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 86 if (haslck) \ 87 mtx_unlock(lck); \ 88 haslck = 0; \ 89} while (0) 90 91TASKQUEUE_DEFINE_THREAD(kqueue); 92 93static int kevent_copyout(void *arg, struct kevent *kevp, int count); 94static int kevent_copyin(void *arg, struct kevent *kevp, int count); 95static int kqueue_register(struct kqueue *kq, struct kevent *kev, 96 struct thread *td, int waitok); 97static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 98static void kqueue_release(struct kqueue *kq, int locked); 99static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 100 uintptr_t ident, int waitok); 101static void kqueue_task(void *arg, int pending); 102static int kqueue_scan(struct kqueue *kq, int maxevents, 103 struct kevent_copyops *k_ops, 104 const struct timespec *timeout, 105 struct kevent *keva, struct thread *td); 106static void kqueue_wakeup(struct kqueue *kq); 107static struct filterops *kqueue_fo_find(int filt); 108static void kqueue_fo_release(int filt); 109 110static fo_rdwr_t kqueue_read; 111static fo_rdwr_t kqueue_write; 112static fo_truncate_t kqueue_truncate; 113static fo_ioctl_t kqueue_ioctl; 114static fo_poll_t kqueue_poll; 115static fo_kqfilter_t kqueue_kqfilter; 116static fo_stat_t kqueue_stat; 117static fo_close_t kqueue_close; 118 119static struct fileops kqueueops = { 120 .fo_read = kqueue_read, 121 .fo_write = kqueue_write, 122 .fo_truncate = kqueue_truncate, 123 .fo_ioctl = kqueue_ioctl, 124 .fo_poll = kqueue_poll, 125 .fo_kqfilter = kqueue_kqfilter, 126 .fo_stat = kqueue_stat, 127 .fo_close = kqueue_close, 128 .fo_chmod = invfo_chmod, 129 .fo_chown = invfo_chown, 130 .fo_sendfile = invfo_sendfile, 131}; 132 133static int knote_attach(struct knote *kn, struct kqueue *kq); 134static void knote_drop(struct knote *kn, struct thread *td); 135static void knote_enqueue(struct knote *kn); 136static void knote_dequeue(struct knote *kn); 137static void knote_init(void); 138static struct knote *knote_alloc(int waitok); 139static void knote_free(struct knote *kn); 140 141static void filt_kqdetach(struct knote *kn); 142static int filt_kqueue(struct knote *kn, long hint); 143static int filt_procattach(struct knote *kn); 144static void filt_procdetach(struct knote *kn); 145static int filt_proc(struct knote *kn, long hint); 146static int filt_fileattach(struct knote *kn); 147static void filt_timerexpire(void *knx); 148static int filt_timerattach(struct knote *kn); 149static void filt_timerdetach(struct knote *kn); 150static int filt_timer(struct knote *kn, long hint); 151static int filt_userattach(struct knote *kn); 152static void filt_userdetach(struct knote *kn); 153static int filt_user(struct knote *kn, long hint); 154static void filt_usertouch(struct knote *kn, struct kevent *kev, 155 u_long type); 156 157static struct filterops file_filtops = { 158 .f_isfd = 1, 159 .f_attach = filt_fileattach, 160}; 161static struct filterops kqread_filtops = { 162 .f_isfd = 1, 163 .f_detach = filt_kqdetach, 164 .f_event = filt_kqueue, 165}; 166/* XXX - move to kern_proc.c? */ 167static struct filterops proc_filtops = { 168 .f_isfd = 0, 169 .f_attach = filt_procattach, 170 .f_detach = filt_procdetach, 171 .f_event = filt_proc, 172}; 173static struct filterops timer_filtops = { 174 .f_isfd = 0, 175 .f_attach = filt_timerattach, 176 .f_detach = filt_timerdetach, 177 .f_event = filt_timer, 178}; 179static struct filterops user_filtops = { 180 .f_attach = filt_userattach, 181 .f_detach = filt_userdetach, 182 .f_event = filt_user, 183 .f_touch = filt_usertouch, 184}; 185 186static uma_zone_t knote_zone; 187static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 188static unsigned int kq_calloutmax = 4 * 1024; 189SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 190 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 191 192/* XXX - ensure not KN_INFLUX?? */ 193#define KNOTE_ACTIVATE(kn, islock) do { \ 194 if ((islock)) \ 195 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 196 else \ 197 KQ_LOCK((kn)->kn_kq); \ 198 (kn)->kn_status |= KN_ACTIVE; \ 199 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 200 knote_enqueue((kn)); \ 201 if (!(islock)) \ 202 KQ_UNLOCK((kn)->kn_kq); \ 203} while(0) 204#define KQ_LOCK(kq) do { \ 205 mtx_lock(&(kq)->kq_lock); \ 206} while (0) 207#define KQ_FLUX_WAKEUP(kq) do { \ 208 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 209 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 210 wakeup((kq)); \ 211 } \ 212} while (0) 213#define KQ_UNLOCK_FLUX(kq) do { \ 214 KQ_FLUX_WAKEUP(kq); \ 215 mtx_unlock(&(kq)->kq_lock); \ 216} while (0) 217#define KQ_UNLOCK(kq) do { \ 218 mtx_unlock(&(kq)->kq_lock); \ 219} while (0) 220#define KQ_OWNED(kq) do { \ 221 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 222} while (0) 223#define KQ_NOTOWNED(kq) do { \ 224 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 225} while (0) 226#define KN_LIST_LOCK(kn) do { \ 227 if (kn->kn_knlist != NULL) \ 228 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 229} while (0) 230#define KN_LIST_UNLOCK(kn) do { \ 231 if (kn->kn_knlist != NULL) \ 232 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 233} while (0) 234#define KNL_ASSERT_LOCK(knl, islocked) do { \ 235 if (islocked) \ 236 KNL_ASSERT_LOCKED(knl); \ 237 else \ 238 KNL_ASSERT_UNLOCKED(knl); \ 239} while (0) 240#ifdef INVARIANTS 241#define KNL_ASSERT_LOCKED(knl) do { \ 242 knl->kl_assert_locked((knl)->kl_lockarg); \ 243} while (0) 244#define KNL_ASSERT_UNLOCKED(knl) do { \ 245 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 246} while (0) 247#else /* !INVARIANTS */ 248#define KNL_ASSERT_LOCKED(knl) do {} while(0) 249#define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 250#endif /* INVARIANTS */ 251 252#define KN_HASHSIZE 64 /* XXX should be tunable */ 253#define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 254 255static int 256filt_nullattach(struct knote *kn) 257{ 258 259 return (ENXIO); 260}; 261 262struct filterops null_filtops = { 263 .f_isfd = 0, 264 .f_attach = filt_nullattach, 265}; 266 267/* XXX - make SYSINIT to add these, and move into respective modules. */ 268extern struct filterops sig_filtops; 269extern struct filterops fs_filtops; 270 271/* 272 * Table for for all system-defined filters. 273 */ 274static struct mtx filterops_lock; 275MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 276 MTX_DEF); 277static struct { 278 struct filterops *for_fop; 279 int for_refcnt; 280} sysfilt_ops[EVFILT_SYSCOUNT] = { 281 { &file_filtops }, /* EVFILT_READ */ 282 { &file_filtops }, /* EVFILT_WRITE */ 283 { &null_filtops }, /* EVFILT_AIO */ 284 { &file_filtops }, /* EVFILT_VNODE */ 285 { &proc_filtops }, /* EVFILT_PROC */ 286 { &sig_filtops }, /* EVFILT_SIGNAL */ 287 { &timer_filtops }, /* EVFILT_TIMER */ 288 { &null_filtops }, /* former EVFILT_NETDEV */ 289 { &fs_filtops }, /* EVFILT_FS */ 290 { &null_filtops }, /* EVFILT_LIO */ 291 { &user_filtops }, /* EVFILT_USER */ 292}; 293 294/* 295 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 296 * method. 297 */ 298static int 299filt_fileattach(struct knote *kn) 300{ 301 302 return (fo_kqfilter(kn->kn_fp, kn)); 303} 304 305/*ARGSUSED*/ 306static int 307kqueue_kqfilter(struct file *fp, struct knote *kn) 308{ 309 struct kqueue *kq = kn->kn_fp->f_data; 310 311 if (kn->kn_filter != EVFILT_READ) 312 return (EINVAL); 313 314 kn->kn_status |= KN_KQUEUE; 315 kn->kn_fop = &kqread_filtops; 316 knlist_add(&kq->kq_sel.si_note, kn, 0); 317 318 return (0); 319} 320 321static void 322filt_kqdetach(struct knote *kn) 323{ 324 struct kqueue *kq = kn->kn_fp->f_data; 325 326 knlist_remove(&kq->kq_sel.si_note, kn, 0); 327} 328 329/*ARGSUSED*/ 330static int 331filt_kqueue(struct knote *kn, long hint) 332{ 333 struct kqueue *kq = kn->kn_fp->f_data; 334 335 kn->kn_data = kq->kq_count; 336 return (kn->kn_data > 0); 337} 338 339/* XXX - move to kern_proc.c? */ 340static int 341filt_procattach(struct knote *kn) 342{ 343 struct proc *p; 344 int immediate; 345 int error; 346 347 immediate = 0; 348 p = pfind(kn->kn_id); 349 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 350 p = zpfind(kn->kn_id); 351 immediate = 1; 352 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 353 immediate = 1; 354 } 355 356 if (p == NULL) 357 return (ESRCH); 358 if ((error = p_cansee(curthread, p))) { 359 PROC_UNLOCK(p); 360 return (error); 361 } 362 363 kn->kn_ptr.p_proc = p; 364 kn->kn_flags |= EV_CLEAR; /* automatically set */ 365 366 /* 367 * internal flag indicating registration done by kernel 368 */ 369 if (kn->kn_flags & EV_FLAG1) { 370 kn->kn_data = kn->kn_sdata; /* ppid */ 371 kn->kn_fflags = NOTE_CHILD; 372 kn->kn_flags &= ~EV_FLAG1; 373 } 374 375 if (immediate == 0) 376 knlist_add(&p->p_klist, kn, 1); 377 378 /* 379 * Immediately activate any exit notes if the target process is a 380 * zombie. This is necessary to handle the case where the target 381 * process, e.g. a child, dies before the kevent is registered. 382 */ 383 if (immediate && filt_proc(kn, NOTE_EXIT)) 384 KNOTE_ACTIVATE(kn, 0); 385 386 PROC_UNLOCK(p); 387 388 return (0); 389} 390 391/* 392 * The knote may be attached to a different process, which may exit, 393 * leaving nothing for the knote to be attached to. So when the process 394 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 395 * it will be deleted when read out. However, as part of the knote deletion, 396 * this routine is called, so a check is needed to avoid actually performing 397 * a detach, because the original process does not exist any more. 398 */ 399/* XXX - move to kern_proc.c? */ 400static void 401filt_procdetach(struct knote *kn) 402{ 403 struct proc *p; 404 405 p = kn->kn_ptr.p_proc; 406 knlist_remove(&p->p_klist, kn, 0); 407 kn->kn_ptr.p_proc = NULL; 408} 409 410/* XXX - move to kern_proc.c? */ 411static int 412filt_proc(struct knote *kn, long hint) 413{ 414 struct proc *p = kn->kn_ptr.p_proc; 415 u_int event; 416 417 /* 418 * mask off extra data 419 */ 420 event = (u_int)hint & NOTE_PCTRLMASK; 421 422 /* 423 * if the user is interested in this event, record it. 424 */ 425 if (kn->kn_sfflags & event) 426 kn->kn_fflags |= event; 427 428 /* 429 * process is gone, so flag the event as finished. 430 */ 431 if (event == NOTE_EXIT) { 432 if (!(kn->kn_status & KN_DETACHED)) 433 knlist_remove_inevent(&p->p_klist, kn); 434 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 435 kn->kn_ptr.p_proc = NULL; 436 if (kn->kn_fflags & NOTE_EXIT) 437 kn->kn_data = p->p_xstat; 438 if (kn->kn_fflags == 0) 439 kn->kn_flags |= EV_DROP; 440 return (1); 441 } 442 443 return (kn->kn_fflags != 0); 444} 445 446/* 447 * Called when the process forked. It mostly does the same as the 448 * knote(), activating all knotes registered to be activated when the 449 * process forked. Additionally, for each knote attached to the 450 * parent, check whether user wants to track the new process. If so 451 * attach a new knote to it, and immediately report an event with the 452 * child's pid. 453 */ 454void 455knote_fork(struct knlist *list, int pid) 456{ 457 struct kqueue *kq; 458 struct knote *kn; 459 struct kevent kev; 460 int error; 461 462 if (list == NULL) 463 return; 464 list->kl_lock(list->kl_lockarg); 465 466 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 467 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 468 continue; 469 kq = kn->kn_kq; 470 KQ_LOCK(kq); 471 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 472 KQ_UNLOCK(kq); 473 continue; 474 } 475 476 /* 477 * The same as knote(), activate the event. 478 */ 479 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 480 kn->kn_status |= KN_HASKQLOCK; 481 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 482 KNOTE_ACTIVATE(kn, 1); 483 kn->kn_status &= ~KN_HASKQLOCK; 484 KQ_UNLOCK(kq); 485 continue; 486 } 487 488 /* 489 * The NOTE_TRACK case. In addition to the activation 490 * of the event, we need to register new event to 491 * track the child. Drop the locks in preparation for 492 * the call to kqueue_register(). 493 */ 494 kn->kn_status |= KN_INFLUX; 495 KQ_UNLOCK(kq); 496 list->kl_unlock(list->kl_lockarg); 497 498 /* 499 * Activate existing knote and register a knote with 500 * new process. 501 */ 502 kev.ident = pid; 503 kev.filter = kn->kn_filter; 504 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 505 kev.fflags = kn->kn_sfflags; 506 kev.data = kn->kn_id; /* parent */ 507 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 508 error = kqueue_register(kq, &kev, NULL, 0); 509 if (error) 510 kn->kn_fflags |= NOTE_TRACKERR; 511 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 512 KNOTE_ACTIVATE(kn, 0); 513 KQ_LOCK(kq); 514 kn->kn_status &= ~KN_INFLUX; 515 KQ_UNLOCK_FLUX(kq); 516 list->kl_lock(list->kl_lockarg); 517 } 518 list->kl_unlock(list->kl_lockarg); 519} 520 521/* 522 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 523 * interval timer support code. 524 */ 525static __inline sbintime_t 526timer2sbintime(intptr_t data) 527{ 528 529 return (SBT_1MS * data); 530} 531 532static void 533filt_timerexpire(void *knx) 534{ 535 struct callout *calloutp; 536 struct knote *kn; 537 538 kn = knx; 539 kn->kn_data++; 540 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 541 542 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 543 calloutp = (struct callout *)kn->kn_hook; 544 callout_reset_sbt_on(calloutp, 545 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 546 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 547 } 548} 549 550/* 551 * data contains amount of time to sleep, in milliseconds 552 */ 553static int 554filt_timerattach(struct knote *kn) 555{ 556 struct callout *calloutp; 557 sbintime_t to; 558 unsigned int ncallouts; 559 560 if ((intptr_t)kn->kn_sdata < 0) 561 return (EINVAL); 562 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 563 kn->kn_sdata = 1; 564 to = timer2sbintime(kn->kn_sdata); 565 if (to < 0) 566 return (EINVAL); 567 568 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 569 do { 570 if (ncallouts >= kq_calloutmax) 571 return (ENOMEM); 572 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 573 &ncallouts, ncallouts + 1, memory_order_relaxed, 574 memory_order_relaxed)); 575 576 kn->kn_flags |= EV_CLEAR; /* automatically set */ 577 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 578 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 579 callout_init(calloutp, CALLOUT_MPSAFE); 580 kn->kn_hook = calloutp; 581 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 582 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 583 584 return (0); 585} 586 587static void 588filt_timerdetach(struct knote *kn) 589{ 590 struct callout *calloutp; 591 unsigned int old; 592 593 calloutp = (struct callout *)kn->kn_hook; 594 callout_drain(calloutp); 595 free(calloutp, M_KQUEUE); 596 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 597 KASSERT(old > 0, ("Number of callouts cannot become negative")); 598 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 599} 600 601static int 602filt_timer(struct knote *kn, long hint) 603{ 604 605 return (kn->kn_data != 0); 606} 607 608static int 609filt_userattach(struct knote *kn) 610{ 611 612 /* 613 * EVFILT_USER knotes are not attached to anything in the kernel. 614 */ 615 kn->kn_hook = NULL; 616 if (kn->kn_fflags & NOTE_TRIGGER) 617 kn->kn_hookid = 1; 618 else 619 kn->kn_hookid = 0; 620 return (0); 621} 622 623static void 624filt_userdetach(__unused struct knote *kn) 625{ 626 627 /* 628 * EVFILT_USER knotes are not attached to anything in the kernel. 629 */ 630} 631 632static int 633filt_user(struct knote *kn, __unused long hint) 634{ 635 636 return (kn->kn_hookid); 637} 638 639static void 640filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 641{ 642 u_int ffctrl; 643 644 switch (type) { 645 case EVENT_REGISTER: 646 if (kev->fflags & NOTE_TRIGGER) 647 kn->kn_hookid = 1; 648 649 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 650 kev->fflags &= NOTE_FFLAGSMASK; 651 switch (ffctrl) { 652 case NOTE_FFNOP: 653 break; 654 655 case NOTE_FFAND: 656 kn->kn_sfflags &= kev->fflags; 657 break; 658 659 case NOTE_FFOR: 660 kn->kn_sfflags |= kev->fflags; 661 break; 662 663 case NOTE_FFCOPY: 664 kn->kn_sfflags = kev->fflags; 665 break; 666 667 default: 668 /* XXX Return error? */ 669 break; 670 } 671 kn->kn_sdata = kev->data; 672 if (kev->flags & EV_CLEAR) { 673 kn->kn_hookid = 0; 674 kn->kn_data = 0; 675 kn->kn_fflags = 0; 676 } 677 break; 678 679 case EVENT_PROCESS: 680 *kev = kn->kn_kevent; 681 kev->fflags = kn->kn_sfflags; 682 kev->data = kn->kn_sdata; 683 if (kn->kn_flags & EV_CLEAR) { 684 kn->kn_hookid = 0; 685 kn->kn_data = 0; 686 kn->kn_fflags = 0; 687 } 688 break; 689 690 default: 691 panic("filt_usertouch() - invalid type (%ld)", type); 692 break; 693 } 694} 695 696int 697sys_kqueue(struct thread *td, struct kqueue_args *uap) 698{ 699 struct filedesc *fdp; 700 struct kqueue *kq; 701 struct file *fp; 702 int fd, error; 703 704 fdp = td->td_proc->p_fd; 705 error = falloc(td, &fp, &fd, 0); 706 if (error) 707 goto done2; 708 709 /* An extra reference on `fp' has been held for us by falloc(). */ 710 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 711 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 712 TAILQ_INIT(&kq->kq_head); 713 kq->kq_fdp = fdp; 714 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 715 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 716 717 FILEDESC_XLOCK(fdp); 718 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 719 FILEDESC_XUNLOCK(fdp); 720 721 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 722 fdrop(fp, td); 723 724 td->td_retval[0] = fd; 725done2: 726 return (error); 727} 728 729#ifndef _SYS_SYSPROTO_H_ 730struct kevent_args { 731 int fd; 732 const struct kevent *changelist; 733 int nchanges; 734 struct kevent *eventlist; 735 int nevents; 736 const struct timespec *timeout; 737}; 738#endif 739int 740sys_kevent(struct thread *td, struct kevent_args *uap) 741{ 742 struct timespec ts, *tsp; 743 struct kevent_copyops k_ops = { uap, 744 kevent_copyout, 745 kevent_copyin}; 746 int error; 747#ifdef KTRACE 748 struct uio ktruio; 749 struct iovec ktriov; 750 struct uio *ktruioin = NULL; 751 struct uio *ktruioout = NULL; 752#endif 753 754 if (uap->timeout != NULL) { 755 error = copyin(uap->timeout, &ts, sizeof(ts)); 756 if (error) 757 return (error); 758 tsp = &ts; 759 } else 760 tsp = NULL; 761 762#ifdef KTRACE 763 if (KTRPOINT(td, KTR_GENIO)) { 764 ktriov.iov_base = uap->changelist; 765 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 766 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 767 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 768 .uio_td = td }; 769 ktruioin = cloneuio(&ktruio); 770 ktriov.iov_base = uap->eventlist; 771 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 772 ktruioout = cloneuio(&ktruio); 773 } 774#endif 775 776 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 777 &k_ops, tsp); 778 779#ifdef KTRACE 780 if (ktruioin != NULL) { 781 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 782 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 783 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 784 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 785 } 786#endif 787 788 return (error); 789} 790 791/* 792 * Copy 'count' items into the destination list pointed to by uap->eventlist. 793 */ 794static int 795kevent_copyout(void *arg, struct kevent *kevp, int count) 796{ 797 struct kevent_args *uap; 798 int error; 799 800 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 801 uap = (struct kevent_args *)arg; 802 803 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 804 if (error == 0) 805 uap->eventlist += count; 806 return (error); 807} 808 809/* 810 * Copy 'count' items from the list pointed to by uap->changelist. 811 */ 812static int 813kevent_copyin(void *arg, struct kevent *kevp, int count) 814{ 815 struct kevent_args *uap; 816 int error; 817 818 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 819 uap = (struct kevent_args *)arg; 820 821 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 822 if (error == 0) 823 uap->changelist += count; 824 return (error); 825} 826 827int 828kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 829 struct kevent_copyops *k_ops, const struct timespec *timeout) 830{ 831 struct kevent keva[KQ_NEVENTS]; 832 struct kevent *kevp, *changes; 833 struct kqueue *kq; 834 struct file *fp; 835 cap_rights_t rights; 836 int i, n, nerrors, error; 837 838 cap_rights_init(&rights); 839 if (nchanges > 0) 840 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 841 if (nevents > 0) 842 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 843 error = fget(td, fd, &rights, &fp); 844 if (error != 0) 845 return (error); 846 847 error = kqueue_acquire(fp, &kq); 848 if (error != 0) 849 goto done_norel; 850 851 nerrors = 0; 852 853 while (nchanges > 0) { 854 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 855 error = k_ops->k_copyin(k_ops->arg, keva, n); 856 if (error) 857 goto done; 858 changes = keva; 859 for (i = 0; i < n; i++) { 860 kevp = &changes[i]; 861 if (!kevp->filter) 862 continue; 863 kevp->flags &= ~EV_SYSFLAGS; 864 error = kqueue_register(kq, kevp, td, 1); 865 if (error || (kevp->flags & EV_RECEIPT)) { 866 if (nevents != 0) { 867 kevp->flags = EV_ERROR; 868 kevp->data = error; 869 (void) k_ops->k_copyout(k_ops->arg, 870 kevp, 1); 871 nevents--; 872 nerrors++; 873 } else { 874 goto done; 875 } 876 } 877 } 878 nchanges -= n; 879 } 880 if (nerrors) { 881 td->td_retval[0] = nerrors; 882 error = 0; 883 goto done; 884 } 885 886 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 887done: 888 kqueue_release(kq, 0); 889done_norel: 890 fdrop(fp, td); 891 return (error); 892} 893 894int 895kqueue_add_filteropts(int filt, struct filterops *filtops) 896{ 897 int error; 898 899 error = 0; 900 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 901 printf( 902"trying to add a filterop that is out of range: %d is beyond %d\n", 903 ~filt, EVFILT_SYSCOUNT); 904 return EINVAL; 905 } 906 mtx_lock(&filterops_lock); 907 if (sysfilt_ops[~filt].for_fop != &null_filtops && 908 sysfilt_ops[~filt].for_fop != NULL) 909 error = EEXIST; 910 else { 911 sysfilt_ops[~filt].for_fop = filtops; 912 sysfilt_ops[~filt].for_refcnt = 0; 913 } 914 mtx_unlock(&filterops_lock); 915 916 return (error); 917} 918 919int 920kqueue_del_filteropts(int filt) 921{ 922 int error; 923 924 error = 0; 925 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 926 return EINVAL; 927 928 mtx_lock(&filterops_lock); 929 if (sysfilt_ops[~filt].for_fop == &null_filtops || 930 sysfilt_ops[~filt].for_fop == NULL) 931 error = EINVAL; 932 else if (sysfilt_ops[~filt].for_refcnt != 0) 933 error = EBUSY; 934 else { 935 sysfilt_ops[~filt].for_fop = &null_filtops; 936 sysfilt_ops[~filt].for_refcnt = 0; 937 } 938 mtx_unlock(&filterops_lock); 939 940 return error; 941} 942 943static struct filterops * 944kqueue_fo_find(int filt) 945{ 946 947 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 948 return NULL; 949 950 mtx_lock(&filterops_lock); 951 sysfilt_ops[~filt].for_refcnt++; 952 if (sysfilt_ops[~filt].for_fop == NULL) 953 sysfilt_ops[~filt].for_fop = &null_filtops; 954 mtx_unlock(&filterops_lock); 955 956 return sysfilt_ops[~filt].for_fop; 957} 958 959static void 960kqueue_fo_release(int filt) 961{ 962 963 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 964 return; 965 966 mtx_lock(&filterops_lock); 967 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 968 ("filter object refcount not valid on release")); 969 sysfilt_ops[~filt].for_refcnt--; 970 mtx_unlock(&filterops_lock); 971} 972 973/* 974 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 975 * influence if memory allocation should wait. Make sure it is 0 if you 976 * hold any mutexes. 977 */ 978static int 979kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 980{ 981 struct filterops *fops; 982 struct file *fp; 983 struct knote *kn, *tkn; 984 cap_rights_t rights; 985 int error, filt, event; 986 int haskqglobal, filedesc_unlock; 987 988 fp = NULL; 989 kn = NULL; 990 error = 0; 991 haskqglobal = 0; 992 filedesc_unlock = 0; 993 994 filt = kev->filter; 995 fops = kqueue_fo_find(filt); 996 if (fops == NULL) 997 return EINVAL; 998 999 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1000 1001findkn: 1002 if (fops->f_isfd) { 1003 KASSERT(td != NULL, ("td is NULL")); 1004 error = fget(td, kev->ident, 1005 cap_rights_init(&rights, CAP_EVENT), &fp); 1006 if (error) 1007 goto done; 1008 1009 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1010 kev->ident, 0) != 0) { 1011 /* try again */ 1012 fdrop(fp, td); 1013 fp = NULL; 1014 error = kqueue_expand(kq, fops, kev->ident, waitok); 1015 if (error) 1016 goto done; 1017 goto findkn; 1018 } 1019 1020 if (fp->f_type == DTYPE_KQUEUE) { 1021 /* 1022 * if we add some inteligence about what we are doing, 1023 * we should be able to support events on ourselves. 1024 * We need to know when we are doing this to prevent 1025 * getting both the knlist lock and the kq lock since 1026 * they are the same thing. 1027 */ 1028 if (fp->f_data == kq) { 1029 error = EINVAL; 1030 goto done; 1031 } 1032 1033 /* 1034 * Pre-lock the filedesc before the global 1035 * lock mutex, see the comment in 1036 * kqueue_close(). 1037 */ 1038 FILEDESC_XLOCK(td->td_proc->p_fd); 1039 filedesc_unlock = 1; 1040 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1041 } 1042 1043 KQ_LOCK(kq); 1044 if (kev->ident < kq->kq_knlistsize) { 1045 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1046 if (kev->filter == kn->kn_filter) 1047 break; 1048 } 1049 } else { 1050 if ((kev->flags & EV_ADD) == EV_ADD) 1051 kqueue_expand(kq, fops, kev->ident, waitok); 1052 1053 KQ_LOCK(kq); 1054 if (kq->kq_knhashmask != 0) { 1055 struct klist *list; 1056 1057 list = &kq->kq_knhash[ 1058 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1059 SLIST_FOREACH(kn, list, kn_link) 1060 if (kev->ident == kn->kn_id && 1061 kev->filter == kn->kn_filter) 1062 break; 1063 } 1064 } 1065 1066 /* knote is in the process of changing, wait for it to stablize. */ 1067 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1068 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1069 if (filedesc_unlock) { 1070 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1071 filedesc_unlock = 0; 1072 } 1073 kq->kq_state |= KQ_FLUXWAIT; 1074 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1075 if (fp != NULL) { 1076 fdrop(fp, td); 1077 fp = NULL; 1078 } 1079 goto findkn; 1080 } 1081 1082 /* 1083 * kn now contains the matching knote, or NULL if no match 1084 */ 1085 if (kn == NULL) { 1086 if (kev->flags & EV_ADD) { 1087 kn = tkn; 1088 tkn = NULL; 1089 if (kn == NULL) { 1090 KQ_UNLOCK(kq); 1091 error = ENOMEM; 1092 goto done; 1093 } 1094 kn->kn_fp = fp; 1095 kn->kn_kq = kq; 1096 kn->kn_fop = fops; 1097 /* 1098 * apply reference counts to knote structure, and 1099 * do not release it at the end of this routine. 1100 */ 1101 fops = NULL; 1102 fp = NULL; 1103 1104 kn->kn_sfflags = kev->fflags; 1105 kn->kn_sdata = kev->data; 1106 kev->fflags = 0; 1107 kev->data = 0; 1108 kn->kn_kevent = *kev; 1109 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1110 EV_ENABLE | EV_DISABLE); 1111 kn->kn_status = KN_INFLUX|KN_DETACHED; 1112 1113 error = knote_attach(kn, kq); 1114 KQ_UNLOCK(kq); 1115 if (error != 0) { 1116 tkn = kn; 1117 goto done; 1118 } 1119 1120 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1121 knote_drop(kn, td); 1122 goto done; 1123 } 1124 KN_LIST_LOCK(kn); 1125 goto done_ev_add; 1126 } else { 1127 /* No matching knote and the EV_ADD flag is not set. */ 1128 KQ_UNLOCK(kq); 1129 error = ENOENT; 1130 goto done; 1131 } 1132 } 1133 1134 if (kev->flags & EV_DELETE) { 1135 kn->kn_status |= KN_INFLUX; 1136 KQ_UNLOCK(kq); 1137 if (!(kn->kn_status & KN_DETACHED)) 1138 kn->kn_fop->f_detach(kn); 1139 knote_drop(kn, td); 1140 goto done; 1141 } 1142 1143 /* 1144 * The user may change some filter values after the initial EV_ADD, 1145 * but doing so will not reset any filter which has already been 1146 * triggered. 1147 */ 1148 kn->kn_status |= KN_INFLUX; 1149 KQ_UNLOCK(kq); 1150 KN_LIST_LOCK(kn); 1151 kn->kn_kevent.udata = kev->udata; 1152 if (!fops->f_isfd && fops->f_touch != NULL) { 1153 fops->f_touch(kn, kev, EVENT_REGISTER); 1154 } else { 1155 kn->kn_sfflags = kev->fflags; 1156 kn->kn_sdata = kev->data; 1157 } 1158 1159 /* 1160 * We can get here with kn->kn_knlist == NULL. This can happen when 1161 * the initial attach event decides that the event is "completed" 1162 * already. i.e. filt_procattach is called on a zombie process. It 1163 * will call filt_proc which will remove it from the list, and NULL 1164 * kn_knlist. 1165 */ 1166done_ev_add: 1167 event = kn->kn_fop->f_event(kn, 0); 1168 KQ_LOCK(kq); 1169 if (event) 1170 KNOTE_ACTIVATE(kn, 1); 1171 kn->kn_status &= ~KN_INFLUX; 1172 KN_LIST_UNLOCK(kn); 1173 1174 if ((kev->flags & EV_DISABLE) && 1175 ((kn->kn_status & KN_DISABLED) == 0)) { 1176 kn->kn_status |= KN_DISABLED; 1177 } 1178 1179 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1180 kn->kn_status &= ~KN_DISABLED; 1181 if ((kn->kn_status & KN_ACTIVE) && 1182 ((kn->kn_status & KN_QUEUED) == 0)) 1183 knote_enqueue(kn); 1184 } 1185 KQ_UNLOCK_FLUX(kq); 1186 1187done: 1188 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1189 if (filedesc_unlock) 1190 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1191 if (fp != NULL) 1192 fdrop(fp, td); 1193 if (tkn != NULL) 1194 knote_free(tkn); 1195 if (fops != NULL) 1196 kqueue_fo_release(filt); 1197 return (error); 1198} 1199 1200static int 1201kqueue_acquire(struct file *fp, struct kqueue **kqp) 1202{ 1203 int error; 1204 struct kqueue *kq; 1205 1206 error = 0; 1207 1208 kq = fp->f_data; 1209 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1210 return (EBADF); 1211 *kqp = kq; 1212 KQ_LOCK(kq); 1213 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1214 KQ_UNLOCK(kq); 1215 return (EBADF); 1216 } 1217 kq->kq_refcnt++; 1218 KQ_UNLOCK(kq); 1219 1220 return error; 1221} 1222 1223static void 1224kqueue_release(struct kqueue *kq, int locked) 1225{ 1226 if (locked) 1227 KQ_OWNED(kq); 1228 else 1229 KQ_LOCK(kq); 1230 kq->kq_refcnt--; 1231 if (kq->kq_refcnt == 1) 1232 wakeup(&kq->kq_refcnt); 1233 if (!locked) 1234 KQ_UNLOCK(kq); 1235} 1236 1237static void 1238kqueue_schedtask(struct kqueue *kq) 1239{ 1240 1241 KQ_OWNED(kq); 1242 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1243 ("scheduling kqueue task while draining")); 1244 1245 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1246 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1247 kq->kq_state |= KQ_TASKSCHED; 1248 } 1249} 1250 1251/* 1252 * Expand the kq to make sure we have storage for fops/ident pair. 1253 * 1254 * Return 0 on success (or no work necessary), return errno on failure. 1255 * 1256 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1257 * If kqueue_register is called from a non-fd context, there usually/should 1258 * be no locks held. 1259 */ 1260static int 1261kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1262 int waitok) 1263{ 1264 struct klist *list, *tmp_knhash, *to_free; 1265 u_long tmp_knhashmask; 1266 int size; 1267 int fd; 1268 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1269 1270 KQ_NOTOWNED(kq); 1271 1272 to_free = NULL; 1273 if (fops->f_isfd) { 1274 fd = ident; 1275 if (kq->kq_knlistsize <= fd) { 1276 size = kq->kq_knlistsize; 1277 while (size <= fd) 1278 size += KQEXTENT; 1279 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1280 if (list == NULL) 1281 return ENOMEM; 1282 KQ_LOCK(kq); 1283 if (kq->kq_knlistsize > fd) { 1284 to_free = list; 1285 list = NULL; 1286 } else { 1287 if (kq->kq_knlist != NULL) { 1288 bcopy(kq->kq_knlist, list, 1289 kq->kq_knlistsize * sizeof(*list)); 1290 to_free = kq->kq_knlist; 1291 kq->kq_knlist = NULL; 1292 } 1293 bzero((caddr_t)list + 1294 kq->kq_knlistsize * sizeof(*list), 1295 (size - kq->kq_knlistsize) * sizeof(*list)); 1296 kq->kq_knlistsize = size; 1297 kq->kq_knlist = list; 1298 } 1299 KQ_UNLOCK(kq); 1300 } 1301 } else { 1302 if (kq->kq_knhashmask == 0) { 1303 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1304 &tmp_knhashmask); 1305 if (tmp_knhash == NULL) 1306 return ENOMEM; 1307 KQ_LOCK(kq); 1308 if (kq->kq_knhashmask == 0) { 1309 kq->kq_knhash = tmp_knhash; 1310 kq->kq_knhashmask = tmp_knhashmask; 1311 } else { 1312 to_free = tmp_knhash; 1313 } 1314 KQ_UNLOCK(kq); 1315 } 1316 } 1317 free(to_free, M_KQUEUE); 1318 1319 KQ_NOTOWNED(kq); 1320 return 0; 1321} 1322 1323static void 1324kqueue_task(void *arg, int pending) 1325{ 1326 struct kqueue *kq; 1327 int haskqglobal; 1328 1329 haskqglobal = 0; 1330 kq = arg; 1331 1332 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1333 KQ_LOCK(kq); 1334 1335 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1336 1337 kq->kq_state &= ~KQ_TASKSCHED; 1338 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1339 wakeup(&kq->kq_state); 1340 } 1341 KQ_UNLOCK(kq); 1342 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1343} 1344 1345/* 1346 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1347 * We treat KN_MARKER knotes as if they are INFLUX. 1348 */ 1349static int 1350kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1351 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1352{ 1353 struct kevent *kevp; 1354 struct knote *kn, *marker; 1355 sbintime_t asbt, rsbt; 1356 int count, error, haskqglobal, influx, nkev, touch; 1357 1358 count = maxevents; 1359 nkev = 0; 1360 error = 0; 1361 haskqglobal = 0; 1362 1363 if (maxevents == 0) 1364 goto done_nl; 1365 1366 rsbt = 0; 1367 if (tsp != NULL) { 1368 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1369 tsp->tv_nsec >= 1000000000) { 1370 error = EINVAL; 1371 goto done_nl; 1372 } 1373 if (timespecisset(tsp)) { 1374 if (tsp->tv_sec <= INT32_MAX) { 1375 rsbt = tstosbt(*tsp); 1376 if (TIMESEL(&asbt, rsbt)) 1377 asbt += tc_tick_sbt; 1378 if (asbt <= INT64_MAX - rsbt) 1379 asbt += rsbt; 1380 else 1381 asbt = 0; 1382 rsbt >>= tc_precexp; 1383 } else 1384 asbt = 0; 1385 } else 1386 asbt = -1; 1387 } else 1388 asbt = 0; 1389 marker = knote_alloc(1); 1390 if (marker == NULL) { 1391 error = ENOMEM; 1392 goto done_nl; 1393 } 1394 marker->kn_status = KN_MARKER; 1395 KQ_LOCK(kq); 1396 1397retry: 1398 kevp = keva; 1399 if (kq->kq_count == 0) { 1400 if (asbt == -1) { 1401 error = EWOULDBLOCK; 1402 } else { 1403 kq->kq_state |= KQ_SLEEP; 1404 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1405 "kqread", asbt, rsbt, C_ABSOLUTE); 1406 } 1407 if (error == 0) 1408 goto retry; 1409 /* don't restart after signals... */ 1410 if (error == ERESTART) 1411 error = EINTR; 1412 else if (error == EWOULDBLOCK) 1413 error = 0; 1414 goto done; 1415 } 1416 1417 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1418 influx = 0; 1419 while (count) { 1420 KQ_OWNED(kq); 1421 kn = TAILQ_FIRST(&kq->kq_head); 1422 1423 if ((kn->kn_status == KN_MARKER && kn != marker) || 1424 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1425 if (influx) { 1426 influx = 0; 1427 KQ_FLUX_WAKEUP(kq); 1428 } 1429 kq->kq_state |= KQ_FLUXWAIT; 1430 error = msleep(kq, &kq->kq_lock, PSOCK, 1431 "kqflxwt", 0); 1432 continue; 1433 } 1434 1435 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1436 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1437 kn->kn_status &= ~KN_QUEUED; 1438 kq->kq_count--; 1439 continue; 1440 } 1441 if (kn == marker) { 1442 KQ_FLUX_WAKEUP(kq); 1443 if (count == maxevents) 1444 goto retry; 1445 goto done; 1446 } 1447 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1448 ("KN_INFLUX set when not suppose to be")); 1449 1450 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1451 kn->kn_status &= ~KN_QUEUED; 1452 kn->kn_status |= KN_INFLUX; 1453 kq->kq_count--; 1454 KQ_UNLOCK(kq); 1455 /* 1456 * We don't need to lock the list since we've marked 1457 * it _INFLUX. 1458 */ 1459 if (!(kn->kn_status & KN_DETACHED)) 1460 kn->kn_fop->f_detach(kn); 1461 knote_drop(kn, td); 1462 KQ_LOCK(kq); 1463 continue; 1464 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1465 kn->kn_status &= ~KN_QUEUED; 1466 kn->kn_status |= KN_INFLUX; 1467 kq->kq_count--; 1468 KQ_UNLOCK(kq); 1469 /* 1470 * We don't need to lock the list since we've marked 1471 * it _INFLUX. 1472 */ 1473 *kevp = kn->kn_kevent; 1474 if (!(kn->kn_status & KN_DETACHED)) 1475 kn->kn_fop->f_detach(kn); 1476 knote_drop(kn, td); 1477 KQ_LOCK(kq); 1478 kn = NULL; 1479 } else { 1480 kn->kn_status |= KN_INFLUX; 1481 KQ_UNLOCK(kq); 1482 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1483 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1484 KN_LIST_LOCK(kn); 1485 if (kn->kn_fop->f_event(kn, 0) == 0) { 1486 KQ_LOCK(kq); 1487 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1488 kn->kn_status &= 1489 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1490 kq->kq_count--; 1491 KN_LIST_UNLOCK(kn); 1492 influx = 1; 1493 continue; 1494 } 1495 touch = (!kn->kn_fop->f_isfd && 1496 kn->kn_fop->f_touch != NULL); 1497 if (touch) 1498 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1499 else 1500 *kevp = kn->kn_kevent; 1501 KQ_LOCK(kq); 1502 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1503 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1504 /* 1505 * Manually clear knotes who weren't 1506 * 'touch'ed. 1507 */ 1508 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1509 kn->kn_data = 0; 1510 kn->kn_fflags = 0; 1511 } 1512 if (kn->kn_flags & EV_DISPATCH) 1513 kn->kn_status |= KN_DISABLED; 1514 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1515 kq->kq_count--; 1516 } else 1517 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1518 1519 kn->kn_status &= ~(KN_INFLUX); 1520 KN_LIST_UNLOCK(kn); 1521 influx = 1; 1522 } 1523 1524 /* we are returning a copy to the user */ 1525 kevp++; 1526 nkev++; 1527 count--; 1528 1529 if (nkev == KQ_NEVENTS) { 1530 influx = 0; 1531 KQ_UNLOCK_FLUX(kq); 1532 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1533 nkev = 0; 1534 kevp = keva; 1535 KQ_LOCK(kq); 1536 if (error) 1537 break; 1538 } 1539 } 1540 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1541done: 1542 KQ_OWNED(kq); 1543 KQ_UNLOCK_FLUX(kq); 1544 knote_free(marker); 1545done_nl: 1546 KQ_NOTOWNED(kq); 1547 if (nkev != 0) 1548 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1549 td->td_retval[0] = maxevents - count; 1550 return (error); 1551} 1552 1553/* 1554 * XXX 1555 * This could be expanded to call kqueue_scan, if desired. 1556 */ 1557/*ARGSUSED*/ 1558static int 1559kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1560 int flags, struct thread *td) 1561{ 1562 return (ENXIO); 1563} 1564 1565/*ARGSUSED*/ 1566static int 1567kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1568 int flags, struct thread *td) 1569{ 1570 return (ENXIO); 1571} 1572 1573/*ARGSUSED*/ 1574static int 1575kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1576 struct thread *td) 1577{ 1578 1579 return (EINVAL); 1580} 1581 1582/*ARGSUSED*/ 1583static int 1584kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1585 struct ucred *active_cred, struct thread *td) 1586{ 1587 /* 1588 * Enabling sigio causes two major problems: 1589 * 1) infinite recursion: 1590 * Synopsys: kevent is being used to track signals and have FIOASYNC 1591 * set. On receipt of a signal this will cause a kqueue to recurse 1592 * into itself over and over. Sending the sigio causes the kqueue 1593 * to become ready, which in turn posts sigio again, forever. 1594 * Solution: this can be solved by setting a flag in the kqueue that 1595 * we have a SIGIO in progress. 1596 * 2) locking problems: 1597 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1598 * us above the proc and pgrp locks. 1599 * Solution: Post a signal using an async mechanism, being sure to 1600 * record a generation count in the delivery so that we do not deliver 1601 * a signal to the wrong process. 1602 * 1603 * Note, these two mechanisms are somewhat mutually exclusive! 1604 */ 1605#if 0 1606 struct kqueue *kq; 1607 1608 kq = fp->f_data; 1609 switch (cmd) { 1610 case FIOASYNC: 1611 if (*(int *)data) { 1612 kq->kq_state |= KQ_ASYNC; 1613 } else { 1614 kq->kq_state &= ~KQ_ASYNC; 1615 } 1616 return (0); 1617 1618 case FIOSETOWN: 1619 return (fsetown(*(int *)data, &kq->kq_sigio)); 1620 1621 case FIOGETOWN: 1622 *(int *)data = fgetown(&kq->kq_sigio); 1623 return (0); 1624 } 1625#endif 1626 1627 return (ENOTTY); 1628} 1629 1630/*ARGSUSED*/ 1631static int 1632kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1633 struct thread *td) 1634{ 1635 struct kqueue *kq; 1636 int revents = 0; 1637 int error; 1638 1639 if ((error = kqueue_acquire(fp, &kq))) 1640 return POLLERR; 1641 1642 KQ_LOCK(kq); 1643 if (events & (POLLIN | POLLRDNORM)) { 1644 if (kq->kq_count) { 1645 revents |= events & (POLLIN | POLLRDNORM); 1646 } else { 1647 selrecord(td, &kq->kq_sel); 1648 if (SEL_WAITING(&kq->kq_sel)) 1649 kq->kq_state |= KQ_SEL; 1650 } 1651 } 1652 kqueue_release(kq, 1); 1653 KQ_UNLOCK(kq); 1654 return (revents); 1655} 1656 1657/*ARGSUSED*/ 1658static int 1659kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1660 struct thread *td) 1661{ 1662 1663 bzero((void *)st, sizeof *st); 1664 /* 1665 * We no longer return kq_count because the unlocked value is useless. 1666 * If you spent all this time getting the count, why not spend your 1667 * syscall better by calling kevent? 1668 * 1669 * XXX - This is needed for libc_r. 1670 */ 1671 st->st_mode = S_IFIFO; 1672 return (0); 1673} 1674 1675/*ARGSUSED*/ 1676static int 1677kqueue_close(struct file *fp, struct thread *td) 1678{ 1679 struct kqueue *kq = fp->f_data; 1680 struct filedesc *fdp; 1681 struct knote *kn; 1682 int i; 1683 int error; 1684 int filedesc_unlock; 1685 1686 if ((error = kqueue_acquire(fp, &kq))) 1687 return error; 1688 1689 filedesc_unlock = 0; 1690 KQ_LOCK(kq); 1691 1692 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1693 ("kqueue already closing")); 1694 kq->kq_state |= KQ_CLOSING; 1695 if (kq->kq_refcnt > 1) 1696 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1697 1698 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1699 fdp = kq->kq_fdp; 1700 1701 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1702 ("kqueue's knlist not empty")); 1703 1704 for (i = 0; i < kq->kq_knlistsize; i++) { 1705 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1706 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1707 kq->kq_state |= KQ_FLUXWAIT; 1708 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1709 continue; 1710 } 1711 kn->kn_status |= KN_INFLUX; 1712 KQ_UNLOCK(kq); 1713 if (!(kn->kn_status & KN_DETACHED)) 1714 kn->kn_fop->f_detach(kn); 1715 knote_drop(kn, td); 1716 KQ_LOCK(kq); 1717 } 1718 } 1719 if (kq->kq_knhashmask != 0) { 1720 for (i = 0; i <= kq->kq_knhashmask; i++) { 1721 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1722 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1723 kq->kq_state |= KQ_FLUXWAIT; 1724 msleep(kq, &kq->kq_lock, PSOCK, 1725 "kqclo2", 0); 1726 continue; 1727 } 1728 kn->kn_status |= KN_INFLUX; 1729 KQ_UNLOCK(kq); 1730 if (!(kn->kn_status & KN_DETACHED)) 1731 kn->kn_fop->f_detach(kn); 1732 knote_drop(kn, td); 1733 KQ_LOCK(kq); 1734 } 1735 } 1736 } 1737 1738 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1739 kq->kq_state |= KQ_TASKDRAIN; 1740 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1741 } 1742 1743 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1744 selwakeuppri(&kq->kq_sel, PSOCK); 1745 if (!SEL_WAITING(&kq->kq_sel)) 1746 kq->kq_state &= ~KQ_SEL; 1747 } 1748 1749 KQ_UNLOCK(kq); 1750 1751 /* 1752 * We could be called due to the knote_drop() doing fdrop(), 1753 * called from kqueue_register(). In this case the global 1754 * lock is owned, and filedesc sx is locked before, to not 1755 * take the sleepable lock after non-sleepable. 1756 */ 1757 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1758 FILEDESC_XLOCK(fdp); 1759 filedesc_unlock = 1; 1760 } else 1761 filedesc_unlock = 0; 1762 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1763 if (filedesc_unlock) 1764 FILEDESC_XUNLOCK(fdp); 1765 1766 seldrain(&kq->kq_sel); 1767 knlist_destroy(&kq->kq_sel.si_note); 1768 mtx_destroy(&kq->kq_lock); 1769 kq->kq_fdp = NULL; 1770 1771 if (kq->kq_knhash != NULL) 1772 free(kq->kq_knhash, M_KQUEUE); 1773 if (kq->kq_knlist != NULL) 1774 free(kq->kq_knlist, M_KQUEUE); 1775 1776 funsetown(&kq->kq_sigio); 1777 free(kq, M_KQUEUE); 1778 fp->f_data = NULL; 1779 1780 return (0); 1781} 1782 1783static void 1784kqueue_wakeup(struct kqueue *kq) 1785{ 1786 KQ_OWNED(kq); 1787 1788 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1789 kq->kq_state &= ~KQ_SLEEP; 1790 wakeup(kq); 1791 } 1792 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1793 selwakeuppri(&kq->kq_sel, PSOCK); 1794 if (!SEL_WAITING(&kq->kq_sel)) 1795 kq->kq_state &= ~KQ_SEL; 1796 } 1797 if (!knlist_empty(&kq->kq_sel.si_note)) 1798 kqueue_schedtask(kq); 1799 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1800 pgsigio(&kq->kq_sigio, SIGIO, 0); 1801 } 1802} 1803 1804/* 1805 * Walk down a list of knotes, activating them if their event has triggered. 1806 * 1807 * There is a possibility to optimize in the case of one kq watching another. 1808 * Instead of scheduling a task to wake it up, you could pass enough state 1809 * down the chain to make up the parent kqueue. Make this code functional 1810 * first. 1811 */ 1812void 1813knote(struct knlist *list, long hint, int lockflags) 1814{ 1815 struct kqueue *kq; 1816 struct knote *kn; 1817 int error; 1818 1819 if (list == NULL) 1820 return; 1821 1822 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1823 1824 if ((lockflags & KNF_LISTLOCKED) == 0) 1825 list->kl_lock(list->kl_lockarg); 1826 1827 /* 1828 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1829 * the kqueue scheduling, but this will introduce four 1830 * lock/unlock's for each knote to test. If we do, continue to use 1831 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1832 * only safe if you want to remove the current item, which we are 1833 * not doing. 1834 */ 1835 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1836 kq = kn->kn_kq; 1837 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1838 KQ_LOCK(kq); 1839 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1840 KQ_UNLOCK(kq); 1841 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1842 kn->kn_status |= KN_INFLUX; 1843 KQ_UNLOCK(kq); 1844 error = kn->kn_fop->f_event(kn, hint); 1845 KQ_LOCK(kq); 1846 kn->kn_status &= ~KN_INFLUX; 1847 if (error) 1848 KNOTE_ACTIVATE(kn, 1); 1849 KQ_UNLOCK_FLUX(kq); 1850 } else { 1851 kn->kn_status |= KN_HASKQLOCK; 1852 if (kn->kn_fop->f_event(kn, hint)) 1853 KNOTE_ACTIVATE(kn, 1); 1854 kn->kn_status &= ~KN_HASKQLOCK; 1855 KQ_UNLOCK(kq); 1856 } 1857 } 1858 kq = NULL; 1859 } 1860 if ((lockflags & KNF_LISTLOCKED) == 0) 1861 list->kl_unlock(list->kl_lockarg); 1862} 1863 1864/* 1865 * add a knote to a knlist 1866 */ 1867void 1868knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1869{ 1870 KNL_ASSERT_LOCK(knl, islocked); 1871 KQ_NOTOWNED(kn->kn_kq); 1872 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1873 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1874 if (!islocked) 1875 knl->kl_lock(knl->kl_lockarg); 1876 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1877 if (!islocked) 1878 knl->kl_unlock(knl->kl_lockarg); 1879 KQ_LOCK(kn->kn_kq); 1880 kn->kn_knlist = knl; 1881 kn->kn_status &= ~KN_DETACHED; 1882 KQ_UNLOCK(kn->kn_kq); 1883} 1884 1885static void 1886knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1887{ 1888 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1889 KNL_ASSERT_LOCK(knl, knlislocked); 1890 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1891 if (!kqislocked) 1892 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1893 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1894 if (!knlislocked) 1895 knl->kl_lock(knl->kl_lockarg); 1896 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1897 kn->kn_knlist = NULL; 1898 if (!knlislocked) 1899 knl->kl_unlock(knl->kl_lockarg); 1900 if (!kqislocked) 1901 KQ_LOCK(kn->kn_kq); 1902 kn->kn_status |= KN_DETACHED; 1903 if (!kqislocked) 1904 KQ_UNLOCK(kn->kn_kq); 1905} 1906 1907/* 1908 * remove knote from the specified knlist 1909 */ 1910void 1911knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1912{ 1913 1914 knlist_remove_kq(knl, kn, islocked, 0); 1915} 1916 1917/* 1918 * remove knote from the specified knlist while in f_event handler. 1919 */ 1920void 1921knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1922{ 1923 1924 knlist_remove_kq(knl, kn, 1, 1925 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1926} 1927 1928int 1929knlist_empty(struct knlist *knl) 1930{ 1931 1932 KNL_ASSERT_LOCKED(knl); 1933 return SLIST_EMPTY(&knl->kl_list); 1934} 1935 1936static struct mtx knlist_lock; 1937MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1938 MTX_DEF); 1939static void knlist_mtx_lock(void *arg); 1940static void knlist_mtx_unlock(void *arg); 1941 1942static void 1943knlist_mtx_lock(void *arg) 1944{ 1945 1946 mtx_lock((struct mtx *)arg); 1947} 1948 1949static void 1950knlist_mtx_unlock(void *arg) 1951{ 1952 1953 mtx_unlock((struct mtx *)arg); 1954} 1955 1956static void 1957knlist_mtx_assert_locked(void *arg) 1958{ 1959 1960 mtx_assert((struct mtx *)arg, MA_OWNED); 1961} 1962 1963static void 1964knlist_mtx_assert_unlocked(void *arg) 1965{ 1966 1967 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1968} 1969 1970static void 1971knlist_rw_rlock(void *arg) 1972{ 1973 1974 rw_rlock((struct rwlock *)arg); 1975} 1976 1977static void 1978knlist_rw_runlock(void *arg) 1979{ 1980 1981 rw_runlock((struct rwlock *)arg); 1982} 1983 1984static void 1985knlist_rw_assert_locked(void *arg) 1986{ 1987 1988 rw_assert((struct rwlock *)arg, RA_LOCKED); 1989} 1990 1991static void 1992knlist_rw_assert_unlocked(void *arg) 1993{ 1994 1995 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 1996} 1997 1998void 1999knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2000 void (*kl_unlock)(void *), 2001 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2002{ 2003 2004 if (lock == NULL) 2005 knl->kl_lockarg = &knlist_lock; 2006 else 2007 knl->kl_lockarg = lock; 2008 2009 if (kl_lock == NULL) 2010 knl->kl_lock = knlist_mtx_lock; 2011 else 2012 knl->kl_lock = kl_lock; 2013 if (kl_unlock == NULL) 2014 knl->kl_unlock = knlist_mtx_unlock; 2015 else 2016 knl->kl_unlock = kl_unlock; 2017 if (kl_assert_locked == NULL) 2018 knl->kl_assert_locked = knlist_mtx_assert_locked; 2019 else 2020 knl->kl_assert_locked = kl_assert_locked; 2021 if (kl_assert_unlocked == NULL) 2022 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2023 else 2024 knl->kl_assert_unlocked = kl_assert_unlocked; 2025 2026 SLIST_INIT(&knl->kl_list); 2027} 2028 2029void 2030knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2031{ 2032 2033 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2034} 2035 2036void 2037knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2038{ 2039 2040 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2041 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2042} 2043 2044void 2045knlist_destroy(struct knlist *knl) 2046{ 2047 2048#ifdef INVARIANTS 2049 /* 2050 * if we run across this error, we need to find the offending 2051 * driver and have it call knlist_clear or knlist_delete. 2052 */ 2053 if (!SLIST_EMPTY(&knl->kl_list)) 2054 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2055#endif 2056 2057 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2058 SLIST_INIT(&knl->kl_list); 2059} 2060 2061/* 2062 * Even if we are locked, we may need to drop the lock to allow any influx 2063 * knotes time to "settle". 2064 */ 2065void 2066knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2067{ 2068 struct knote *kn, *kn2; 2069 struct kqueue *kq; 2070 2071 if (islocked) 2072 KNL_ASSERT_LOCKED(knl); 2073 else { 2074 KNL_ASSERT_UNLOCKED(knl); 2075again: /* need to reacquire lock since we have dropped it */ 2076 knl->kl_lock(knl->kl_lockarg); 2077 } 2078 2079 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2080 kq = kn->kn_kq; 2081 KQ_LOCK(kq); 2082 if ((kn->kn_status & KN_INFLUX)) { 2083 KQ_UNLOCK(kq); 2084 continue; 2085 } 2086 knlist_remove_kq(knl, kn, 1, 1); 2087 if (killkn) { 2088 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2089 KQ_UNLOCK(kq); 2090 knote_drop(kn, td); 2091 } else { 2092 /* Make sure cleared knotes disappear soon */ 2093 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2094 KQ_UNLOCK(kq); 2095 } 2096 kq = NULL; 2097 } 2098 2099 if (!SLIST_EMPTY(&knl->kl_list)) { 2100 /* there are still KN_INFLUX remaining */ 2101 kn = SLIST_FIRST(&knl->kl_list); 2102 kq = kn->kn_kq; 2103 KQ_LOCK(kq); 2104 KASSERT(kn->kn_status & KN_INFLUX, 2105 ("knote removed w/o list lock")); 2106 knl->kl_unlock(knl->kl_lockarg); 2107 kq->kq_state |= KQ_FLUXWAIT; 2108 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2109 kq = NULL; 2110 goto again; 2111 } 2112 2113 if (islocked) 2114 KNL_ASSERT_LOCKED(knl); 2115 else { 2116 knl->kl_unlock(knl->kl_lockarg); 2117 KNL_ASSERT_UNLOCKED(knl); 2118 } 2119} 2120 2121/* 2122 * Remove all knotes referencing a specified fd must be called with FILEDESC 2123 * lock. This prevents a race where a new fd comes along and occupies the 2124 * entry and we attach a knote to the fd. 2125 */ 2126void 2127knote_fdclose(struct thread *td, int fd) 2128{ 2129 struct filedesc *fdp = td->td_proc->p_fd; 2130 struct kqueue *kq; 2131 struct knote *kn; 2132 int influx; 2133 2134 FILEDESC_XLOCK_ASSERT(fdp); 2135 2136 /* 2137 * We shouldn't have to worry about new kevents appearing on fd 2138 * since filedesc is locked. 2139 */ 2140 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2141 KQ_LOCK(kq); 2142 2143again: 2144 influx = 0; 2145 while (kq->kq_knlistsize > fd && 2146 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2147 if (kn->kn_status & KN_INFLUX) { 2148 /* someone else might be waiting on our knote */ 2149 if (influx) 2150 wakeup(kq); 2151 kq->kq_state |= KQ_FLUXWAIT; 2152 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2153 goto again; 2154 } 2155 kn->kn_status |= KN_INFLUX; 2156 KQ_UNLOCK(kq); 2157 if (!(kn->kn_status & KN_DETACHED)) 2158 kn->kn_fop->f_detach(kn); 2159 knote_drop(kn, td); 2160 influx = 1; 2161 KQ_LOCK(kq); 2162 } 2163 KQ_UNLOCK_FLUX(kq); 2164 } 2165} 2166 2167static int 2168knote_attach(struct knote *kn, struct kqueue *kq) 2169{ 2170 struct klist *list; 2171 2172 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2173 KQ_OWNED(kq); 2174 2175 if (kn->kn_fop->f_isfd) { 2176 if (kn->kn_id >= kq->kq_knlistsize) 2177 return ENOMEM; 2178 list = &kq->kq_knlist[kn->kn_id]; 2179 } else { 2180 if (kq->kq_knhash == NULL) 2181 return ENOMEM; 2182 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2183 } 2184 2185 SLIST_INSERT_HEAD(list, kn, kn_link); 2186 2187 return 0; 2188} 2189 2190/* 2191 * knote must already have been detached using the f_detach method. 2192 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2193 * to prevent other removal. 2194 */ 2195static void 2196knote_drop(struct knote *kn, struct thread *td) 2197{ 2198 struct kqueue *kq; 2199 struct klist *list; 2200 2201 kq = kn->kn_kq; 2202 2203 KQ_NOTOWNED(kq); 2204 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2205 ("knote_drop called without KN_INFLUX set in kn_status")); 2206 2207 KQ_LOCK(kq); 2208 if (kn->kn_fop->f_isfd) 2209 list = &kq->kq_knlist[kn->kn_id]; 2210 else 2211 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2212 2213 if (!SLIST_EMPTY(list)) 2214 SLIST_REMOVE(list, kn, knote, kn_link); 2215 if (kn->kn_status & KN_QUEUED) 2216 knote_dequeue(kn); 2217 KQ_UNLOCK_FLUX(kq); 2218 2219 if (kn->kn_fop->f_isfd) { 2220 fdrop(kn->kn_fp, td); 2221 kn->kn_fp = NULL; 2222 } 2223 kqueue_fo_release(kn->kn_kevent.filter); 2224 kn->kn_fop = NULL; 2225 knote_free(kn); 2226} 2227 2228static void 2229knote_enqueue(struct knote *kn) 2230{ 2231 struct kqueue *kq = kn->kn_kq; 2232 2233 KQ_OWNED(kn->kn_kq); 2234 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2235 2236 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2237 kn->kn_status |= KN_QUEUED; 2238 kq->kq_count++; 2239 kqueue_wakeup(kq); 2240} 2241 2242static void 2243knote_dequeue(struct knote *kn) 2244{ 2245 struct kqueue *kq = kn->kn_kq; 2246 2247 KQ_OWNED(kn->kn_kq); 2248 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2249 2250 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2251 kn->kn_status &= ~KN_QUEUED; 2252 kq->kq_count--; 2253} 2254 2255static void 2256knote_init(void) 2257{ 2258 2259 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2260 NULL, NULL, UMA_ALIGN_PTR, 0); 2261} 2262SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2263 2264static struct knote * 2265knote_alloc(int waitok) 2266{ 2267 return ((struct knote *)uma_zalloc(knote_zone, 2268 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2269} 2270 2271static void 2272knote_free(struct knote *kn) 2273{ 2274 if (kn != NULL) 2275 uma_zfree(knote_zone, kn); 2276} 2277 2278/* 2279 * Register the kev w/ the kq specified by fd. 2280 */ 2281int 2282kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2283{ 2284 struct kqueue *kq; 2285 struct file *fp; 2286 cap_rights_t rights; 2287 int error; 2288 2289 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2290 if (error != 0) 2291 return (error); 2292 if ((error = kqueue_acquire(fp, &kq)) != 0) 2293 goto noacquire; 2294 2295 error = kqueue_register(kq, kev, td, waitok); 2296 2297 kqueue_release(kq, 0); 2298 2299noacquire: 2300 fdrop(fp, td); 2301 2302 return error; 2303} 2304