1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 5 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 6 * Copyright (c) 2009 Apple, Inc. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include "opt_ktrace.h" 35 #include "opt_kqueue.h" 36 37 #ifdef COMPAT_FREEBSD11 38 #define _WANT_FREEBSD11_KEVENT 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/capsicum.h> 44 #include <sys/kernel.h> 45 #include <sys/limits.h> 46 #include <sys/lock.h> 47 #include <sys/mutex.h> 48 #include <sys/rwlock.h> 49 #include <sys/proc.h> 50 #include <sys/malloc.h> 51 #include <sys/unistd.h> 52 #include <sys/file.h> 53 #include <sys/filedesc.h> 54 #include <sys/filio.h> 55 #include <sys/fcntl.h> 56 #include <sys/kthread.h> 57 #include <sys/selinfo.h> 58 #include <sys/queue.h> 59 #include <sys/event.h> 60 #include <sys/eventvar.h> 61 #include <sys/poll.h> 62 #include <sys/protosw.h> 63 #include <sys/resourcevar.h> 64 #include <sys/sigio.h> 65 #include <sys/signalvar.h> 66 #include <sys/socket.h> 67 #include <sys/socketvar.h> 68 #include <sys/stat.h> 69 #include <sys/sysctl.h> 70 #include <sys/sysproto.h> 71 #include <sys/syscallsubr.h> 72 #include <sys/taskqueue.h> 73 #include <sys/uio.h> 74 #include <sys/user.h> 75 #ifdef KTRACE 76 #include <sys/ktrace.h> 77 #endif 78 #include <machine/atomic.h> 79 80 #include <vm/uma.h> 81 82 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 83 84 /* 85 * This lock is used if multiple kq locks are required. This possibly 86 * should be made into a per proc lock. 87 */ 88 static struct mtx kq_global; 89 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 90 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 91 if (!haslck) \ 92 mtx_lock(lck); \ 93 haslck = 1; \ 94 } while (0) 95 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 96 if (haslck) \ 97 mtx_unlock(lck); \ 98 haslck = 0; \ 99 } while (0) 100 101 TASKQUEUE_DEFINE_THREAD(kqueue_ctx); 102 103 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 104 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 105 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 106 struct thread *td, int mflag); 107 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 108 static void kqueue_release(struct kqueue *kq, int locked); 109 static void kqueue_destroy(struct kqueue *kq); 110 static void kqueue_drain(struct kqueue *kq, struct thread *td); 111 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 112 uintptr_t ident, int mflag); 113 static void kqueue_task(void *arg, int pending); 114 static int kqueue_scan(struct kqueue *kq, int maxevents, 115 struct kevent_copyops *k_ops, 116 const struct timespec *timeout, 117 struct kevent *keva, struct thread *td); 118 static void kqueue_wakeup(struct kqueue *kq); 119 static struct filterops *kqueue_fo_find(int filt); 120 static void kqueue_fo_release(int filt); 121 struct g_kevent_args; 122 static int kern_kevent_generic(struct thread *td, 123 struct g_kevent_args *uap, 124 struct kevent_copyops *k_ops, const char *struct_name); 125 126 static fo_ioctl_t kqueue_ioctl; 127 static fo_poll_t kqueue_poll; 128 static fo_kqfilter_t kqueue_kqfilter; 129 static fo_stat_t kqueue_stat; 130 static fo_close_t kqueue_close; 131 static fo_fill_kinfo_t kqueue_fill_kinfo; 132 133 static struct fileops kqueueops = { 134 .fo_read = invfo_rdwr, 135 .fo_write = invfo_rdwr, 136 .fo_truncate = invfo_truncate, 137 .fo_ioctl = kqueue_ioctl, 138 .fo_poll = kqueue_poll, 139 .fo_kqfilter = kqueue_kqfilter, 140 .fo_stat = kqueue_stat, 141 .fo_close = kqueue_close, 142 .fo_chmod = invfo_chmod, 143 .fo_chown = invfo_chown, 144 .fo_sendfile = invfo_sendfile, 145 .fo_fill_kinfo = kqueue_fill_kinfo, 146 }; 147 148 static int knote_attach(struct knote *kn, struct kqueue *kq); 149 static void knote_drop(struct knote *kn, struct thread *td); 150 static void knote_drop_detached(struct knote *kn, struct thread *td); 151 static void knote_enqueue(struct knote *kn); 152 static void knote_dequeue(struct knote *kn); 153 static void knote_init(void); 154 static struct knote *knote_alloc(int mflag); 155 static void knote_free(struct knote *kn); 156 157 static void filt_kqdetach(struct knote *kn); 158 static int filt_kqueue(struct knote *kn, long hint); 159 static int filt_procattach(struct knote *kn); 160 static void filt_procdetach(struct knote *kn); 161 static int filt_proc(struct knote *kn, long hint); 162 static int filt_fileattach(struct knote *kn); 163 static void filt_timerexpire(void *knx); 164 static void filt_timerexpire_l(struct knote *kn, bool proc_locked); 165 static int filt_timerattach(struct knote *kn); 166 static void filt_timerdetach(struct knote *kn); 167 static void filt_timerstart(struct knote *kn, sbintime_t to); 168 static void filt_timertouch(struct knote *kn, struct kevent *kev, 169 u_long type); 170 static int filt_timervalidate(struct knote *kn, sbintime_t *to); 171 static int filt_timer(struct knote *kn, long hint); 172 static int filt_userattach(struct knote *kn); 173 static void filt_userdetach(struct knote *kn); 174 static int filt_user(struct knote *kn, long hint); 175 static void filt_usertouch(struct knote *kn, struct kevent *kev, 176 u_long type); 177 178 static struct filterops file_filtops = { 179 .f_isfd = 1, 180 .f_attach = filt_fileattach, 181 }; 182 static struct filterops kqread_filtops = { 183 .f_isfd = 1, 184 .f_detach = filt_kqdetach, 185 .f_event = filt_kqueue, 186 }; 187 /* XXX - move to kern_proc.c? */ 188 static struct filterops proc_filtops = { 189 .f_isfd = 0, 190 .f_attach = filt_procattach, 191 .f_detach = filt_procdetach, 192 .f_event = filt_proc, 193 }; 194 static struct filterops timer_filtops = { 195 .f_isfd = 0, 196 .f_attach = filt_timerattach, 197 .f_detach = filt_timerdetach, 198 .f_event = filt_timer, 199 .f_touch = filt_timertouch, 200 }; 201 static struct filterops user_filtops = { 202 .f_attach = filt_userattach, 203 .f_detach = filt_userdetach, 204 .f_event = filt_user, 205 .f_touch = filt_usertouch, 206 }; 207 208 static uma_zone_t knote_zone; 209 static unsigned int kq_ncallouts = 0; 210 static unsigned int kq_calloutmax = 4 * 1024; 211 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 212 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 213 214 /* XXX - ensure not influx ? */ 215 #define KNOTE_ACTIVATE(kn, islock) do { \ 216 if ((islock)) \ 217 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 218 else \ 219 KQ_LOCK((kn)->kn_kq); \ 220 (kn)->kn_status |= KN_ACTIVE; \ 221 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 222 knote_enqueue((kn)); \ 223 if (!(islock)) \ 224 KQ_UNLOCK((kn)->kn_kq); \ 225 } while (0) 226 #define KQ_LOCK(kq) do { \ 227 mtx_lock(&(kq)->kq_lock); \ 228 } while (0) 229 #define KQ_FLUX_WAKEUP(kq) do { \ 230 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 231 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 232 wakeup((kq)); \ 233 } \ 234 } while (0) 235 #define KQ_UNLOCK_FLUX(kq) do { \ 236 KQ_FLUX_WAKEUP(kq); \ 237 mtx_unlock(&(kq)->kq_lock); \ 238 } while (0) 239 #define KQ_UNLOCK(kq) do { \ 240 mtx_unlock(&(kq)->kq_lock); \ 241 } while (0) 242 #define KQ_OWNED(kq) do { \ 243 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 244 } while (0) 245 #define KQ_NOTOWNED(kq) do { \ 246 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 247 } while (0) 248 249 static struct knlist * 250 kn_list_lock(struct knote *kn) 251 { 252 struct knlist *knl; 253 254 knl = kn->kn_knlist; 255 if (knl != NULL) 256 knl->kl_lock(knl->kl_lockarg); 257 return (knl); 258 } 259 260 static void 261 kn_list_unlock(struct knlist *knl) 262 { 263 bool do_free; 264 265 if (knl == NULL) 266 return; 267 do_free = knl->kl_autodestroy && knlist_empty(knl); 268 knl->kl_unlock(knl->kl_lockarg); 269 if (do_free) { 270 knlist_destroy(knl); 271 free(knl, M_KQUEUE); 272 } 273 } 274 275 static bool 276 kn_in_flux(struct knote *kn) 277 { 278 279 return (kn->kn_influx > 0); 280 } 281 282 static void 283 kn_enter_flux(struct knote *kn) 284 { 285 286 KQ_OWNED(kn->kn_kq); 287 MPASS(kn->kn_influx < INT_MAX); 288 kn->kn_influx++; 289 } 290 291 static bool 292 kn_leave_flux(struct knote *kn) 293 { 294 295 KQ_OWNED(kn->kn_kq); 296 MPASS(kn->kn_influx > 0); 297 kn->kn_influx--; 298 return (kn->kn_influx == 0); 299 } 300 301 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 302 if (islocked) \ 303 KNL_ASSERT_LOCKED(knl); \ 304 else \ 305 KNL_ASSERT_UNLOCKED(knl); \ 306 } while (0) 307 #ifdef INVARIANTS 308 #define KNL_ASSERT_LOCKED(knl) do { \ 309 knl->kl_assert_lock((knl)->kl_lockarg, LA_LOCKED); \ 310 } while (0) 311 #define KNL_ASSERT_UNLOCKED(knl) do { \ 312 knl->kl_assert_lock((knl)->kl_lockarg, LA_UNLOCKED); \ 313 } while (0) 314 #else /* !INVARIANTS */ 315 #define KNL_ASSERT_LOCKED(knl) do {} while (0) 316 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 317 #endif /* INVARIANTS */ 318 319 #ifndef KN_HASHSIZE 320 #define KN_HASHSIZE 64 /* XXX should be tunable */ 321 #endif 322 323 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 324 325 static int 326 filt_nullattach(struct knote *kn) 327 { 328 329 return (ENXIO); 330 }; 331 332 struct filterops null_filtops = { 333 .f_isfd = 0, 334 .f_attach = filt_nullattach, 335 }; 336 337 /* XXX - make SYSINIT to add these, and move into respective modules. */ 338 extern struct filterops sig_filtops; 339 extern struct filterops fs_filtops; 340 341 /* 342 * Table for for all system-defined filters. 343 */ 344 static struct mtx filterops_lock; 345 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 346 MTX_DEF); 347 static struct { 348 struct filterops *for_fop; 349 int for_nolock; 350 int for_refcnt; 351 } sysfilt_ops[EVFILT_SYSCOUNT] = { 352 { &file_filtops, 1 }, /* EVFILT_READ */ 353 { &file_filtops, 1 }, /* EVFILT_WRITE */ 354 { &null_filtops }, /* EVFILT_AIO */ 355 { &file_filtops, 1 }, /* EVFILT_VNODE */ 356 { &proc_filtops, 1 }, /* EVFILT_PROC */ 357 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 358 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 359 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 360 { &fs_filtops, 1 }, /* EVFILT_FS */ 361 { &null_filtops }, /* EVFILT_LIO */ 362 { &user_filtops, 1 }, /* EVFILT_USER */ 363 { &null_filtops }, /* EVFILT_SENDFILE */ 364 { &file_filtops, 1 }, /* EVFILT_EMPTY */ 365 }; 366 367 /* 368 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 369 * method. 370 */ 371 static int 372 filt_fileattach(struct knote *kn) 373 { 374 375 return (fo_kqfilter(kn->kn_fp, kn)); 376 } 377 378 /*ARGSUSED*/ 379 static int 380 kqueue_kqfilter(struct file *fp, struct knote *kn) 381 { 382 struct kqueue *kq = kn->kn_fp->f_data; 383 384 if (kn->kn_filter != EVFILT_READ) 385 return (EINVAL); 386 387 kn->kn_status |= KN_KQUEUE; 388 kn->kn_fop = &kqread_filtops; 389 knlist_add(&kq->kq_sel.si_note, kn, 0); 390 391 return (0); 392 } 393 394 static void 395 filt_kqdetach(struct knote *kn) 396 { 397 struct kqueue *kq = kn->kn_fp->f_data; 398 399 knlist_remove(&kq->kq_sel.si_note, kn, 0); 400 } 401 402 /*ARGSUSED*/ 403 static int 404 filt_kqueue(struct knote *kn, long hint) 405 { 406 struct kqueue *kq = kn->kn_fp->f_data; 407 408 kn->kn_data = kq->kq_count; 409 return (kn->kn_data > 0); 410 } 411 412 /* XXX - move to kern_proc.c? */ 413 static int 414 filt_procattach(struct knote *kn) 415 { 416 struct proc *p; 417 int error; 418 bool exiting, immediate; 419 420 exiting = immediate = false; 421 if (kn->kn_sfflags & NOTE_EXIT) 422 p = pfind_any(kn->kn_id); 423 else 424 p = pfind(kn->kn_id); 425 if (p == NULL) 426 return (ESRCH); 427 if (p->p_flag & P_WEXIT) 428 exiting = true; 429 430 if ((error = p_cansee(curthread, p))) { 431 PROC_UNLOCK(p); 432 return (error); 433 } 434 435 kn->kn_ptr.p_proc = p; 436 kn->kn_flags |= EV_CLEAR; /* automatically set */ 437 438 /* 439 * Internal flag indicating registration done by kernel for the 440 * purposes of getting a NOTE_CHILD notification. 441 */ 442 if (kn->kn_flags & EV_FLAG2) { 443 kn->kn_flags &= ~EV_FLAG2; 444 kn->kn_data = kn->kn_sdata; /* ppid */ 445 kn->kn_fflags = NOTE_CHILD; 446 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK); 447 immediate = true; /* Force immediate activation of child note. */ 448 } 449 /* 450 * Internal flag indicating registration done by kernel (for other than 451 * NOTE_CHILD). 452 */ 453 if (kn->kn_flags & EV_FLAG1) { 454 kn->kn_flags &= ~EV_FLAG1; 455 } 456 457 knlist_add(p->p_klist, kn, 1); 458 459 /* 460 * Immediately activate any child notes or, in the case of a zombie 461 * target process, exit notes. The latter is necessary to handle the 462 * case where the target process, e.g. a child, dies before the kevent 463 * is registered. 464 */ 465 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT))) 466 KNOTE_ACTIVATE(kn, 0); 467 468 PROC_UNLOCK(p); 469 470 return (0); 471 } 472 473 /* 474 * The knote may be attached to a different process, which may exit, 475 * leaving nothing for the knote to be attached to. So when the process 476 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 477 * it will be deleted when read out. However, as part of the knote deletion, 478 * this routine is called, so a check is needed to avoid actually performing 479 * a detach, because the original process does not exist any more. 480 */ 481 /* XXX - move to kern_proc.c? */ 482 static void 483 filt_procdetach(struct knote *kn) 484 { 485 486 knlist_remove(kn->kn_knlist, kn, 0); 487 kn->kn_ptr.p_proc = NULL; 488 } 489 490 /* XXX - move to kern_proc.c? */ 491 static int 492 filt_proc(struct knote *kn, long hint) 493 { 494 struct proc *p; 495 u_int event; 496 497 p = kn->kn_ptr.p_proc; 498 if (p == NULL) /* already activated, from attach filter */ 499 return (0); 500 501 /* Mask off extra data. */ 502 event = (u_int)hint & NOTE_PCTRLMASK; 503 504 /* If the user is interested in this event, record it. */ 505 if (kn->kn_sfflags & event) 506 kn->kn_fflags |= event; 507 508 /* Process is gone, so flag the event as finished. */ 509 if (event == NOTE_EXIT) { 510 kn->kn_flags |= EV_EOF | EV_ONESHOT; 511 kn->kn_ptr.p_proc = NULL; 512 if (kn->kn_fflags & NOTE_EXIT) 513 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 514 if (kn->kn_fflags == 0) 515 kn->kn_flags |= EV_DROP; 516 return (1); 517 } 518 519 return (kn->kn_fflags != 0); 520 } 521 522 /* 523 * Called when the process forked. It mostly does the same as the 524 * knote(), activating all knotes registered to be activated when the 525 * process forked. Additionally, for each knote attached to the 526 * parent, check whether user wants to track the new process. If so 527 * attach a new knote to it, and immediately report an event with the 528 * child's pid. 529 */ 530 void 531 knote_fork(struct knlist *list, int pid) 532 { 533 struct kqueue *kq; 534 struct knote *kn; 535 struct kevent kev; 536 int error; 537 538 MPASS(list != NULL); 539 KNL_ASSERT_LOCKED(list); 540 if (SLIST_EMPTY(&list->kl_list)) 541 return; 542 543 memset(&kev, 0, sizeof(kev)); 544 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 545 kq = kn->kn_kq; 546 KQ_LOCK(kq); 547 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 548 KQ_UNLOCK(kq); 549 continue; 550 } 551 552 /* 553 * The same as knote(), activate the event. 554 */ 555 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 556 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 557 KNOTE_ACTIVATE(kn, 1); 558 KQ_UNLOCK(kq); 559 continue; 560 } 561 562 /* 563 * The NOTE_TRACK case. In addition to the activation 564 * of the event, we need to register new events to 565 * track the child. Drop the locks in preparation for 566 * the call to kqueue_register(). 567 */ 568 kn_enter_flux(kn); 569 KQ_UNLOCK(kq); 570 list->kl_unlock(list->kl_lockarg); 571 572 /* 573 * Activate existing knote and register tracking knotes with 574 * new process. 575 * 576 * First register a knote to get just the child notice. This 577 * must be a separate note from a potential NOTE_EXIT 578 * notification since both NOTE_CHILD and NOTE_EXIT are defined 579 * to use the data field (in conflicting ways). 580 */ 581 kev.ident = pid; 582 kev.filter = kn->kn_filter; 583 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | 584 EV_FLAG2; 585 kev.fflags = kn->kn_sfflags; 586 kev.data = kn->kn_id; /* parent */ 587 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 588 error = kqueue_register(kq, &kev, NULL, M_NOWAIT); 589 if (error) 590 kn->kn_fflags |= NOTE_TRACKERR; 591 592 /* 593 * Then register another knote to track other potential events 594 * from the new process. 595 */ 596 kev.ident = pid; 597 kev.filter = kn->kn_filter; 598 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 599 kev.fflags = kn->kn_sfflags; 600 kev.data = kn->kn_id; /* parent */ 601 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 602 error = kqueue_register(kq, &kev, NULL, M_NOWAIT); 603 if (error) 604 kn->kn_fflags |= NOTE_TRACKERR; 605 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 606 KNOTE_ACTIVATE(kn, 0); 607 list->kl_lock(list->kl_lockarg); 608 KQ_LOCK(kq); 609 kn_leave_flux(kn); 610 KQ_UNLOCK_FLUX(kq); 611 } 612 } 613 614 /* 615 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 616 * interval timer support code. 617 */ 618 619 #define NOTE_TIMER_PRECMASK \ 620 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS) 621 622 static sbintime_t 623 timer2sbintime(int64_t data, int flags) 624 { 625 int64_t secs; 626 627 /* 628 * Macros for converting to the fractional second portion of an 629 * sbintime_t using 64bit multiplication to improve precision. 630 */ 631 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 632 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 633 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 634 switch (flags & NOTE_TIMER_PRECMASK) { 635 case NOTE_SECONDS: 636 #ifdef __LP64__ 637 if (data > (SBT_MAX / SBT_1S)) 638 return (SBT_MAX); 639 #endif 640 return ((sbintime_t)data << 32); 641 case NOTE_MSECONDS: /* FALLTHROUGH */ 642 case 0: 643 if (data >= 1000) { 644 secs = data / 1000; 645 #ifdef __LP64__ 646 if (secs > (SBT_MAX / SBT_1S)) 647 return (SBT_MAX); 648 #endif 649 return (secs << 32 | MS_TO_SBT(data % 1000)); 650 } 651 return (MS_TO_SBT(data)); 652 case NOTE_USECONDS: 653 if (data >= 1000000) { 654 secs = data / 1000000; 655 #ifdef __LP64__ 656 if (secs > (SBT_MAX / SBT_1S)) 657 return (SBT_MAX); 658 #endif 659 return (secs << 32 | US_TO_SBT(data % 1000000)); 660 } 661 return (US_TO_SBT(data)); 662 case NOTE_NSECONDS: 663 if (data >= 1000000000) { 664 secs = data / 1000000000; 665 #ifdef __LP64__ 666 if (secs > (SBT_MAX / SBT_1S)) 667 return (SBT_MAX); 668 #endif 669 return (secs << 32 | NS_TO_SBT(data % 1000000000)); 670 } 671 return (NS_TO_SBT(data)); 672 default: 673 break; 674 } 675 return (-1); 676 } 677 678 struct kq_timer_cb_data { 679 struct callout c; 680 struct proc *p; 681 struct knote *kn; 682 int cpuid; 683 TAILQ_ENTRY(kq_timer_cb_data) link; 684 sbintime_t next; /* next timer event fires at */ 685 sbintime_t to; /* precalculated timer period, 0 for abs */ 686 }; 687 688 static void 689 kqtimer_sched_callout(struct kq_timer_cb_data *kc) 690 { 691 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kc->kn, 692 kc->cpuid, C_ABSOLUTE); 693 } 694 695 void 696 kqtimer_proc_continue(struct proc *p) 697 { 698 struct kq_timer_cb_data *kc, *kc1; 699 struct bintime bt; 700 sbintime_t now; 701 702 PROC_LOCK_ASSERT(p, MA_OWNED); 703 704 getboottimebin(&bt); 705 now = bttosbt(bt); 706 707 TAILQ_FOREACH_SAFE(kc, &p->p_kqtim_stop, link, kc1) { 708 TAILQ_REMOVE(&p->p_kqtim_stop, kc, link); 709 if (kc->next <= now) 710 filt_timerexpire_l(kc->kn, true); 711 else 712 kqtimer_sched_callout(kc); 713 } 714 } 715 716 static void 717 filt_timerexpire_l(struct knote *kn, bool proc_locked) 718 { 719 struct kq_timer_cb_data *kc; 720 struct proc *p; 721 uint64_t delta; 722 sbintime_t now; 723 724 kc = kn->kn_ptr.p_v; 725 726 if ((kn->kn_flags & EV_ONESHOT) != 0 || kc->to == 0) { 727 kn->kn_data++; 728 KNOTE_ACTIVATE(kn, 0); 729 return; 730 } 731 732 now = sbinuptime(); 733 if (now >= kc->next) { 734 delta = (now - kc->next) / kc->to; 735 if (delta == 0) 736 delta = 1; 737 kn->kn_data += delta; 738 kc->next += (delta + 1) * kc->to; 739 if (now >= kc->next) /* overflow */ 740 kc->next = now + kc->to; 741 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 742 } 743 744 /* 745 * Initial check for stopped kc->p is racy. It is fine to 746 * miss the set of the stop flags, at worst we would schedule 747 * one more callout. On the other hand, it is not fine to not 748 * schedule when we we missed clearing of the flags, we 749 * recheck them under the lock and observe consistent state. 750 */ 751 p = kc->p; 752 if (P_SHOULDSTOP(p) || P_KILLED(p)) { 753 if (!proc_locked) 754 PROC_LOCK(p); 755 if (P_SHOULDSTOP(p) || P_KILLED(p)) { 756 TAILQ_INSERT_TAIL(&p->p_kqtim_stop, kc, link); 757 if (!proc_locked) 758 PROC_UNLOCK(p); 759 return; 760 } 761 if (!proc_locked) 762 PROC_UNLOCK(p); 763 } 764 kqtimer_sched_callout(kc); 765 } 766 767 static void 768 filt_timerexpire(void *knx) 769 { 770 filt_timerexpire_l(knx, false); 771 } 772 773 /* 774 * data contains amount of time to sleep 775 */ 776 static int 777 filt_timervalidate(struct knote *kn, sbintime_t *to) 778 { 779 struct bintime bt; 780 sbintime_t sbt; 781 782 if (kn->kn_sdata < 0) 783 return (EINVAL); 784 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 785 kn->kn_sdata = 1; 786 /* 787 * The only fflags values supported are the timer unit 788 * (precision) and the absolute time indicator. 789 */ 790 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0) 791 return (EINVAL); 792 793 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 794 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 795 getboottimebin(&bt); 796 sbt = bttosbt(bt); 797 *to -= sbt; 798 } 799 if (*to < 0) 800 return (EINVAL); 801 return (0); 802 } 803 804 static int 805 filt_timerattach(struct knote *kn) 806 { 807 struct kq_timer_cb_data *kc; 808 sbintime_t to; 809 unsigned int ncallouts; 810 int error; 811 812 error = filt_timervalidate(kn, &to); 813 if (error != 0) 814 return (error); 815 816 do { 817 ncallouts = kq_ncallouts; 818 if (ncallouts >= kq_calloutmax) 819 return (ENOMEM); 820 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 821 822 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0) 823 kn->kn_flags |= EV_CLEAR; /* automatically set */ 824 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 825 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 826 kc->kn = kn; 827 kc->p = curproc; 828 kc->cpuid = PCPU_GET(cpuid); 829 callout_init(&kc->c, 1); 830 filt_timerstart(kn, to); 831 832 return (0); 833 } 834 835 static void 836 filt_timerstart(struct knote *kn, sbintime_t to) 837 { 838 struct kq_timer_cb_data *kc; 839 840 kc = kn->kn_ptr.p_v; 841 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 842 kc->next = to; 843 kc->to = 0; 844 } else { 845 kc->next = to + sbinuptime(); 846 kc->to = to; 847 } 848 kqtimer_sched_callout(kc); 849 } 850 851 static void 852 filt_timerdetach(struct knote *kn) 853 { 854 struct kq_timer_cb_data *kc; 855 unsigned int old __unused; 856 857 kc = kn->kn_ptr.p_v; 858 callout_drain(&kc->c); 859 free(kc, M_KQUEUE); 860 old = atomic_fetchadd_int(&kq_ncallouts, -1); 861 KASSERT(old > 0, ("Number of callouts cannot become negative")); 862 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 863 } 864 865 static void 866 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type) 867 { 868 struct kq_timer_cb_data *kc; 869 struct kqueue *kq; 870 sbintime_t to; 871 int error; 872 873 switch (type) { 874 case EVENT_REGISTER: 875 /* Handle re-added timers that update data/fflags */ 876 if (kev->flags & EV_ADD) { 877 kc = kn->kn_ptr.p_v; 878 879 /* Drain any existing callout. */ 880 callout_drain(&kc->c); 881 882 /* Throw away any existing undelivered record 883 * of the timer expiration. This is done under 884 * the presumption that if a process is 885 * re-adding this timer with new parameters, 886 * it is no longer interested in what may have 887 * happened under the old parameters. If it is 888 * interested, it can wait for the expiration, 889 * delete the old timer definition, and then 890 * add the new one. 891 * 892 * This has to be done while the kq is locked: 893 * - if enqueued, dequeue 894 * - make it no longer active 895 * - clear the count of expiration events 896 */ 897 kq = kn->kn_kq; 898 KQ_LOCK(kq); 899 if (kn->kn_status & KN_QUEUED) 900 knote_dequeue(kn); 901 902 kn->kn_status &= ~KN_ACTIVE; 903 kn->kn_data = 0; 904 KQ_UNLOCK(kq); 905 906 /* Reschedule timer based on new data/fflags */ 907 kn->kn_sfflags = kev->fflags; 908 kn->kn_sdata = kev->data; 909 error = filt_timervalidate(kn, &to); 910 if (error != 0) { 911 kn->kn_flags |= EV_ERROR; 912 kn->kn_data = error; 913 } else 914 filt_timerstart(kn, to); 915 } 916 break; 917 918 case EVENT_PROCESS: 919 *kev = kn->kn_kevent; 920 if (kn->kn_flags & EV_CLEAR) { 921 kn->kn_data = 0; 922 kn->kn_fflags = 0; 923 } 924 break; 925 926 default: 927 panic("filt_timertouch() - invalid type (%ld)", type); 928 break; 929 } 930 } 931 932 static int 933 filt_timer(struct knote *kn, long hint) 934 { 935 936 return (kn->kn_data != 0); 937 } 938 939 static int 940 filt_userattach(struct knote *kn) 941 { 942 943 /* 944 * EVFILT_USER knotes are not attached to anything in the kernel. 945 */ 946 kn->kn_hook = NULL; 947 if (kn->kn_fflags & NOTE_TRIGGER) 948 kn->kn_hookid = 1; 949 else 950 kn->kn_hookid = 0; 951 return (0); 952 } 953 954 static void 955 filt_userdetach(__unused struct knote *kn) 956 { 957 958 /* 959 * EVFILT_USER knotes are not attached to anything in the kernel. 960 */ 961 } 962 963 static int 964 filt_user(struct knote *kn, __unused long hint) 965 { 966 967 return (kn->kn_hookid); 968 } 969 970 static void 971 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 972 { 973 u_int ffctrl; 974 975 switch (type) { 976 case EVENT_REGISTER: 977 if (kev->fflags & NOTE_TRIGGER) 978 kn->kn_hookid = 1; 979 980 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 981 kev->fflags &= NOTE_FFLAGSMASK; 982 switch (ffctrl) { 983 case NOTE_FFNOP: 984 break; 985 986 case NOTE_FFAND: 987 kn->kn_sfflags &= kev->fflags; 988 break; 989 990 case NOTE_FFOR: 991 kn->kn_sfflags |= kev->fflags; 992 break; 993 994 case NOTE_FFCOPY: 995 kn->kn_sfflags = kev->fflags; 996 break; 997 998 default: 999 /* XXX Return error? */ 1000 break; 1001 } 1002 kn->kn_sdata = kev->data; 1003 if (kev->flags & EV_CLEAR) { 1004 kn->kn_hookid = 0; 1005 kn->kn_data = 0; 1006 kn->kn_fflags = 0; 1007 } 1008 break; 1009 1010 case EVENT_PROCESS: 1011 *kev = kn->kn_kevent; 1012 kev->fflags = kn->kn_sfflags; 1013 kev->data = kn->kn_sdata; 1014 if (kn->kn_flags & EV_CLEAR) { 1015 kn->kn_hookid = 0; 1016 kn->kn_data = 0; 1017 kn->kn_fflags = 0; 1018 } 1019 break; 1020 1021 default: 1022 panic("filt_usertouch() - invalid type (%ld)", type); 1023 break; 1024 } 1025 } 1026 1027 int 1028 sys_kqueue(struct thread *td, struct kqueue_args *uap) 1029 { 1030 1031 return (kern_kqueue(td, 0, NULL)); 1032 } 1033 1034 static void 1035 kqueue_init(struct kqueue *kq) 1036 { 1037 1038 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 1039 TAILQ_INIT(&kq->kq_head); 1040 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 1041 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 1042 } 1043 1044 int 1045 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 1046 { 1047 struct filedesc *fdp; 1048 struct kqueue *kq; 1049 struct file *fp; 1050 struct ucred *cred; 1051 int fd, error; 1052 1053 fdp = td->td_proc->p_fd; 1054 cred = td->td_ucred; 1055 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 1056 return (ENOMEM); 1057 1058 error = falloc_caps(td, &fp, &fd, flags, fcaps); 1059 if (error != 0) { 1060 chgkqcnt(cred->cr_ruidinfo, -1, 0); 1061 return (error); 1062 } 1063 1064 /* An extra reference on `fp' has been held for us by falloc(). */ 1065 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 1066 kqueue_init(kq); 1067 kq->kq_fdp = fdp; 1068 kq->kq_cred = crhold(cred); 1069 1070 FILEDESC_XLOCK(fdp); 1071 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 1072 FILEDESC_XUNLOCK(fdp); 1073 1074 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 1075 fdrop(fp, td); 1076 1077 td->td_retval[0] = fd; 1078 return (0); 1079 } 1080 1081 struct g_kevent_args { 1082 int fd; 1083 void *changelist; 1084 int nchanges; 1085 void *eventlist; 1086 int nevents; 1087 const struct timespec *timeout; 1088 }; 1089 1090 int 1091 sys_kevent(struct thread *td, struct kevent_args *uap) 1092 { 1093 struct kevent_copyops k_ops = { 1094 .arg = uap, 1095 .k_copyout = kevent_copyout, 1096 .k_copyin = kevent_copyin, 1097 .kevent_size = sizeof(struct kevent), 1098 }; 1099 struct g_kevent_args gk_args = { 1100 .fd = uap->fd, 1101 .changelist = uap->changelist, 1102 .nchanges = uap->nchanges, 1103 .eventlist = uap->eventlist, 1104 .nevents = uap->nevents, 1105 .timeout = uap->timeout, 1106 }; 1107 1108 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent")); 1109 } 1110 1111 static int 1112 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap, 1113 struct kevent_copyops *k_ops, const char *struct_name) 1114 { 1115 struct timespec ts, *tsp; 1116 #ifdef KTRACE 1117 struct kevent *eventlist = uap->eventlist; 1118 #endif 1119 int error; 1120 1121 if (uap->timeout != NULL) { 1122 error = copyin(uap->timeout, &ts, sizeof(ts)); 1123 if (error) 1124 return (error); 1125 tsp = &ts; 1126 } else 1127 tsp = NULL; 1128 1129 #ifdef KTRACE 1130 if (KTRPOINT(td, KTR_STRUCT_ARRAY)) 1131 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist, 1132 uap->nchanges, k_ops->kevent_size); 1133 #endif 1134 1135 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 1136 k_ops, tsp); 1137 1138 #ifdef KTRACE 1139 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY)) 1140 ktrstructarray(struct_name, UIO_USERSPACE, eventlist, 1141 td->td_retval[0], k_ops->kevent_size); 1142 #endif 1143 1144 return (error); 1145 } 1146 1147 /* 1148 * Copy 'count' items into the destination list pointed to by uap->eventlist. 1149 */ 1150 static int 1151 kevent_copyout(void *arg, struct kevent *kevp, int count) 1152 { 1153 struct kevent_args *uap; 1154 int error; 1155 1156 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1157 uap = (struct kevent_args *)arg; 1158 1159 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 1160 if (error == 0) 1161 uap->eventlist += count; 1162 return (error); 1163 } 1164 1165 /* 1166 * Copy 'count' items from the list pointed to by uap->changelist. 1167 */ 1168 static int 1169 kevent_copyin(void *arg, struct kevent *kevp, int count) 1170 { 1171 struct kevent_args *uap; 1172 int error; 1173 1174 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1175 uap = (struct kevent_args *)arg; 1176 1177 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 1178 if (error == 0) 1179 uap->changelist += count; 1180 return (error); 1181 } 1182 1183 #ifdef COMPAT_FREEBSD11 1184 static int 1185 kevent11_copyout(void *arg, struct kevent *kevp, int count) 1186 { 1187 struct freebsd11_kevent_args *uap; 1188 struct kevent_freebsd11 kev11; 1189 int error, i; 1190 1191 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1192 uap = (struct freebsd11_kevent_args *)arg; 1193 1194 for (i = 0; i < count; i++) { 1195 kev11.ident = kevp->ident; 1196 kev11.filter = kevp->filter; 1197 kev11.flags = kevp->flags; 1198 kev11.fflags = kevp->fflags; 1199 kev11.data = kevp->data; 1200 kev11.udata = kevp->udata; 1201 error = copyout(&kev11, uap->eventlist, sizeof(kev11)); 1202 if (error != 0) 1203 break; 1204 uap->eventlist++; 1205 kevp++; 1206 } 1207 return (error); 1208 } 1209 1210 /* 1211 * Copy 'count' items from the list pointed to by uap->changelist. 1212 */ 1213 static int 1214 kevent11_copyin(void *arg, struct kevent *kevp, int count) 1215 { 1216 struct freebsd11_kevent_args *uap; 1217 struct kevent_freebsd11 kev11; 1218 int error, i; 1219 1220 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1221 uap = (struct freebsd11_kevent_args *)arg; 1222 1223 for (i = 0; i < count; i++) { 1224 error = copyin(uap->changelist, &kev11, sizeof(kev11)); 1225 if (error != 0) 1226 break; 1227 kevp->ident = kev11.ident; 1228 kevp->filter = kev11.filter; 1229 kevp->flags = kev11.flags; 1230 kevp->fflags = kev11.fflags; 1231 kevp->data = (uintptr_t)kev11.data; 1232 kevp->udata = kev11.udata; 1233 bzero(&kevp->ext, sizeof(kevp->ext)); 1234 uap->changelist++; 1235 kevp++; 1236 } 1237 return (error); 1238 } 1239 1240 int 1241 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap) 1242 { 1243 struct kevent_copyops k_ops = { 1244 .arg = uap, 1245 .k_copyout = kevent11_copyout, 1246 .k_copyin = kevent11_copyin, 1247 .kevent_size = sizeof(struct kevent_freebsd11), 1248 }; 1249 struct g_kevent_args gk_args = { 1250 .fd = uap->fd, 1251 .changelist = uap->changelist, 1252 .nchanges = uap->nchanges, 1253 .eventlist = uap->eventlist, 1254 .nevents = uap->nevents, 1255 .timeout = uap->timeout, 1256 }; 1257 1258 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11")); 1259 } 1260 #endif 1261 1262 int 1263 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1264 struct kevent_copyops *k_ops, const struct timespec *timeout) 1265 { 1266 cap_rights_t rights; 1267 struct file *fp; 1268 int error; 1269 1270 cap_rights_init_zero(&rights); 1271 if (nchanges > 0) 1272 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE); 1273 if (nevents > 0) 1274 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT); 1275 error = fget(td, fd, &rights, &fp); 1276 if (error != 0) 1277 return (error); 1278 1279 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1280 fdrop(fp, td); 1281 1282 return (error); 1283 } 1284 1285 static int 1286 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1287 struct kevent_copyops *k_ops, const struct timespec *timeout) 1288 { 1289 struct kevent keva[KQ_NEVENTS]; 1290 struct kevent *kevp, *changes; 1291 int i, n, nerrors, error; 1292 1293 nerrors = 0; 1294 while (nchanges > 0) { 1295 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1296 error = k_ops->k_copyin(k_ops->arg, keva, n); 1297 if (error) 1298 return (error); 1299 changes = keva; 1300 for (i = 0; i < n; i++) { 1301 kevp = &changes[i]; 1302 if (!kevp->filter) 1303 continue; 1304 kevp->flags &= ~EV_SYSFLAGS; 1305 error = kqueue_register(kq, kevp, td, M_WAITOK); 1306 if (error || (kevp->flags & EV_RECEIPT)) { 1307 if (nevents == 0) 1308 return (error); 1309 kevp->flags = EV_ERROR; 1310 kevp->data = error; 1311 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1312 nevents--; 1313 nerrors++; 1314 } 1315 } 1316 nchanges -= n; 1317 } 1318 if (nerrors) { 1319 td->td_retval[0] = nerrors; 1320 return (0); 1321 } 1322 1323 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1324 } 1325 1326 int 1327 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1328 struct kevent_copyops *k_ops, const struct timespec *timeout) 1329 { 1330 struct kqueue *kq; 1331 int error; 1332 1333 error = kqueue_acquire(fp, &kq); 1334 if (error != 0) 1335 return (error); 1336 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1337 kqueue_release(kq, 0); 1338 return (error); 1339 } 1340 1341 /* 1342 * Performs a kevent() call on a temporarily created kqueue. This can be 1343 * used to perform one-shot polling, similar to poll() and select(). 1344 */ 1345 int 1346 kern_kevent_anonymous(struct thread *td, int nevents, 1347 struct kevent_copyops *k_ops) 1348 { 1349 struct kqueue kq = {}; 1350 int error; 1351 1352 kqueue_init(&kq); 1353 kq.kq_refcnt = 1; 1354 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1355 kqueue_drain(&kq, td); 1356 kqueue_destroy(&kq); 1357 return (error); 1358 } 1359 1360 int 1361 kqueue_add_filteropts(int filt, struct filterops *filtops) 1362 { 1363 int error; 1364 1365 error = 0; 1366 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1367 printf( 1368 "trying to add a filterop that is out of range: %d is beyond %d\n", 1369 ~filt, EVFILT_SYSCOUNT); 1370 return EINVAL; 1371 } 1372 mtx_lock(&filterops_lock); 1373 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1374 sysfilt_ops[~filt].for_fop != NULL) 1375 error = EEXIST; 1376 else { 1377 sysfilt_ops[~filt].for_fop = filtops; 1378 sysfilt_ops[~filt].for_refcnt = 0; 1379 } 1380 mtx_unlock(&filterops_lock); 1381 1382 return (error); 1383 } 1384 1385 int 1386 kqueue_del_filteropts(int filt) 1387 { 1388 int error; 1389 1390 error = 0; 1391 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1392 return EINVAL; 1393 1394 mtx_lock(&filterops_lock); 1395 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1396 sysfilt_ops[~filt].for_fop == NULL) 1397 error = EINVAL; 1398 else if (sysfilt_ops[~filt].for_refcnt != 0) 1399 error = EBUSY; 1400 else { 1401 sysfilt_ops[~filt].for_fop = &null_filtops; 1402 sysfilt_ops[~filt].for_refcnt = 0; 1403 } 1404 mtx_unlock(&filterops_lock); 1405 1406 return error; 1407 } 1408 1409 static struct filterops * 1410 kqueue_fo_find(int filt) 1411 { 1412 1413 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1414 return NULL; 1415 1416 if (sysfilt_ops[~filt].for_nolock) 1417 return sysfilt_ops[~filt].for_fop; 1418 1419 mtx_lock(&filterops_lock); 1420 sysfilt_ops[~filt].for_refcnt++; 1421 if (sysfilt_ops[~filt].for_fop == NULL) 1422 sysfilt_ops[~filt].for_fop = &null_filtops; 1423 mtx_unlock(&filterops_lock); 1424 1425 return sysfilt_ops[~filt].for_fop; 1426 } 1427 1428 static void 1429 kqueue_fo_release(int filt) 1430 { 1431 1432 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1433 return; 1434 1435 if (sysfilt_ops[~filt].for_nolock) 1436 return; 1437 1438 mtx_lock(&filterops_lock); 1439 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1440 ("filter object refcount not valid on release")); 1441 sysfilt_ops[~filt].for_refcnt--; 1442 mtx_unlock(&filterops_lock); 1443 } 1444 1445 /* 1446 * A ref to kq (obtained via kqueue_acquire) must be held. 1447 */ 1448 static int 1449 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, 1450 int mflag) 1451 { 1452 struct filterops *fops; 1453 struct file *fp; 1454 struct knote *kn, *tkn; 1455 struct knlist *knl; 1456 int error, filt, event; 1457 int haskqglobal, filedesc_unlock; 1458 1459 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1460 return (EINVAL); 1461 1462 fp = NULL; 1463 kn = NULL; 1464 knl = NULL; 1465 error = 0; 1466 haskqglobal = 0; 1467 filedesc_unlock = 0; 1468 1469 filt = kev->filter; 1470 fops = kqueue_fo_find(filt); 1471 if (fops == NULL) 1472 return EINVAL; 1473 1474 if (kev->flags & EV_ADD) { 1475 /* 1476 * Prevent waiting with locks. Non-sleepable 1477 * allocation failures are handled in the loop, only 1478 * if the spare knote appears to be actually required. 1479 */ 1480 tkn = knote_alloc(mflag); 1481 } else { 1482 tkn = NULL; 1483 } 1484 1485 findkn: 1486 if (fops->f_isfd) { 1487 KASSERT(td != NULL, ("td is NULL")); 1488 if (kev->ident > INT_MAX) 1489 error = EBADF; 1490 else 1491 error = fget(td, kev->ident, &cap_event_rights, &fp); 1492 if (error) 1493 goto done; 1494 1495 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1496 kev->ident, M_NOWAIT) != 0) { 1497 /* try again */ 1498 fdrop(fp, td); 1499 fp = NULL; 1500 error = kqueue_expand(kq, fops, kev->ident, mflag); 1501 if (error) 1502 goto done; 1503 goto findkn; 1504 } 1505 1506 if (fp->f_type == DTYPE_KQUEUE) { 1507 /* 1508 * If we add some intelligence about what we are doing, 1509 * we should be able to support events on ourselves. 1510 * We need to know when we are doing this to prevent 1511 * getting both the knlist lock and the kq lock since 1512 * they are the same thing. 1513 */ 1514 if (fp->f_data == kq) { 1515 error = EINVAL; 1516 goto done; 1517 } 1518 1519 /* 1520 * Pre-lock the filedesc before the global 1521 * lock mutex, see the comment in 1522 * kqueue_close(). 1523 */ 1524 FILEDESC_XLOCK(td->td_proc->p_fd); 1525 filedesc_unlock = 1; 1526 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1527 } 1528 1529 KQ_LOCK(kq); 1530 if (kev->ident < kq->kq_knlistsize) { 1531 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1532 if (kev->filter == kn->kn_filter) 1533 break; 1534 } 1535 } else { 1536 if ((kev->flags & EV_ADD) == EV_ADD) { 1537 error = kqueue_expand(kq, fops, kev->ident, mflag); 1538 if (error != 0) 1539 goto done; 1540 } 1541 1542 KQ_LOCK(kq); 1543 1544 /* 1545 * If possible, find an existing knote to use for this kevent. 1546 */ 1547 if (kev->filter == EVFILT_PROC && 1548 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1549 /* This is an internal creation of a process tracking 1550 * note. Don't attempt to coalesce this with an 1551 * existing note. 1552 */ 1553 ; 1554 } else if (kq->kq_knhashmask != 0) { 1555 struct klist *list; 1556 1557 list = &kq->kq_knhash[ 1558 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1559 SLIST_FOREACH(kn, list, kn_link) 1560 if (kev->ident == kn->kn_id && 1561 kev->filter == kn->kn_filter) 1562 break; 1563 } 1564 } 1565 1566 /* knote is in the process of changing, wait for it to stabilize. */ 1567 if (kn != NULL && kn_in_flux(kn)) { 1568 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1569 if (filedesc_unlock) { 1570 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1571 filedesc_unlock = 0; 1572 } 1573 kq->kq_state |= KQ_FLUXWAIT; 1574 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1575 if (fp != NULL) { 1576 fdrop(fp, td); 1577 fp = NULL; 1578 } 1579 goto findkn; 1580 } 1581 1582 /* 1583 * kn now contains the matching knote, or NULL if no match 1584 */ 1585 if (kn == NULL) { 1586 if (kev->flags & EV_ADD) { 1587 kn = tkn; 1588 tkn = NULL; 1589 if (kn == NULL) { 1590 KQ_UNLOCK(kq); 1591 error = ENOMEM; 1592 goto done; 1593 } 1594 kn->kn_fp = fp; 1595 kn->kn_kq = kq; 1596 kn->kn_fop = fops; 1597 /* 1598 * apply reference counts to knote structure, and 1599 * do not release it at the end of this routine. 1600 */ 1601 fops = NULL; 1602 fp = NULL; 1603 1604 kn->kn_sfflags = kev->fflags; 1605 kn->kn_sdata = kev->data; 1606 kev->fflags = 0; 1607 kev->data = 0; 1608 kn->kn_kevent = *kev; 1609 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1610 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1611 kn->kn_status = KN_DETACHED; 1612 if ((kev->flags & EV_DISABLE) != 0) 1613 kn->kn_status |= KN_DISABLED; 1614 kn_enter_flux(kn); 1615 1616 error = knote_attach(kn, kq); 1617 KQ_UNLOCK(kq); 1618 if (error != 0) { 1619 tkn = kn; 1620 goto done; 1621 } 1622 1623 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1624 knote_drop_detached(kn, td); 1625 goto done; 1626 } 1627 knl = kn_list_lock(kn); 1628 goto done_ev_add; 1629 } else { 1630 /* No matching knote and the EV_ADD flag is not set. */ 1631 KQ_UNLOCK(kq); 1632 error = ENOENT; 1633 goto done; 1634 } 1635 } 1636 1637 if (kev->flags & EV_DELETE) { 1638 kn_enter_flux(kn); 1639 KQ_UNLOCK(kq); 1640 knote_drop(kn, td); 1641 goto done; 1642 } 1643 1644 if (kev->flags & EV_FORCEONESHOT) { 1645 kn->kn_flags |= EV_ONESHOT; 1646 KNOTE_ACTIVATE(kn, 1); 1647 } 1648 1649 if ((kev->flags & EV_ENABLE) != 0) 1650 kn->kn_status &= ~KN_DISABLED; 1651 else if ((kev->flags & EV_DISABLE) != 0) 1652 kn->kn_status |= KN_DISABLED; 1653 1654 /* 1655 * The user may change some filter values after the initial EV_ADD, 1656 * but doing so will not reset any filter which has already been 1657 * triggered. 1658 */ 1659 kn->kn_status |= KN_SCAN; 1660 kn_enter_flux(kn); 1661 KQ_UNLOCK(kq); 1662 knl = kn_list_lock(kn); 1663 kn->kn_kevent.udata = kev->udata; 1664 if (!fops->f_isfd && fops->f_touch != NULL) { 1665 fops->f_touch(kn, kev, EVENT_REGISTER); 1666 } else { 1667 kn->kn_sfflags = kev->fflags; 1668 kn->kn_sdata = kev->data; 1669 } 1670 1671 done_ev_add: 1672 /* 1673 * We can get here with kn->kn_knlist == NULL. This can happen when 1674 * the initial attach event decides that the event is "completed" 1675 * already, e.g., filt_procattach() is called on a zombie process. It 1676 * will call filt_proc() which will remove it from the list, and NULL 1677 * kn_knlist. 1678 * 1679 * KN_DISABLED will be stable while the knote is in flux, so the 1680 * unlocked read will not race with an update. 1681 */ 1682 if ((kn->kn_status & KN_DISABLED) == 0) 1683 event = kn->kn_fop->f_event(kn, 0); 1684 else 1685 event = 0; 1686 1687 KQ_LOCK(kq); 1688 if (event) 1689 kn->kn_status |= KN_ACTIVE; 1690 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1691 KN_ACTIVE) 1692 knote_enqueue(kn); 1693 kn->kn_status &= ~KN_SCAN; 1694 kn_leave_flux(kn); 1695 kn_list_unlock(knl); 1696 KQ_UNLOCK_FLUX(kq); 1697 1698 done: 1699 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1700 if (filedesc_unlock) 1701 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1702 if (fp != NULL) 1703 fdrop(fp, td); 1704 knote_free(tkn); 1705 if (fops != NULL) 1706 kqueue_fo_release(filt); 1707 return (error); 1708 } 1709 1710 static int 1711 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1712 { 1713 int error; 1714 struct kqueue *kq; 1715 1716 error = 0; 1717 1718 kq = fp->f_data; 1719 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1720 return (EBADF); 1721 *kqp = kq; 1722 KQ_LOCK(kq); 1723 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1724 KQ_UNLOCK(kq); 1725 return (EBADF); 1726 } 1727 kq->kq_refcnt++; 1728 KQ_UNLOCK(kq); 1729 1730 return error; 1731 } 1732 1733 static void 1734 kqueue_release(struct kqueue *kq, int locked) 1735 { 1736 if (locked) 1737 KQ_OWNED(kq); 1738 else 1739 KQ_LOCK(kq); 1740 kq->kq_refcnt--; 1741 if (kq->kq_refcnt == 1) 1742 wakeup(&kq->kq_refcnt); 1743 if (!locked) 1744 KQ_UNLOCK(kq); 1745 } 1746 1747 static void 1748 kqueue_schedtask(struct kqueue *kq) 1749 { 1750 1751 KQ_OWNED(kq); 1752 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1753 ("scheduling kqueue task while draining")); 1754 1755 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1756 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1757 kq->kq_state |= KQ_TASKSCHED; 1758 } 1759 } 1760 1761 /* 1762 * Expand the kq to make sure we have storage for fops/ident pair. 1763 * 1764 * Return 0 on success (or no work necessary), return errno on failure. 1765 */ 1766 static int 1767 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1768 int mflag) 1769 { 1770 struct klist *list, *tmp_knhash, *to_free; 1771 u_long tmp_knhashmask; 1772 int error, fd, size; 1773 1774 KQ_NOTOWNED(kq); 1775 1776 error = 0; 1777 to_free = NULL; 1778 if (fops->f_isfd) { 1779 fd = ident; 1780 if (kq->kq_knlistsize <= fd) { 1781 size = kq->kq_knlistsize; 1782 while (size <= fd) 1783 size += KQEXTENT; 1784 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1785 if (list == NULL) 1786 return ENOMEM; 1787 KQ_LOCK(kq); 1788 if ((kq->kq_state & KQ_CLOSING) != 0) { 1789 to_free = list; 1790 error = EBADF; 1791 } else if (kq->kq_knlistsize > fd) { 1792 to_free = list; 1793 } else { 1794 if (kq->kq_knlist != NULL) { 1795 bcopy(kq->kq_knlist, list, 1796 kq->kq_knlistsize * sizeof(*list)); 1797 to_free = kq->kq_knlist; 1798 kq->kq_knlist = NULL; 1799 } 1800 bzero((caddr_t)list + 1801 kq->kq_knlistsize * sizeof(*list), 1802 (size - kq->kq_knlistsize) * sizeof(*list)); 1803 kq->kq_knlistsize = size; 1804 kq->kq_knlist = list; 1805 } 1806 KQ_UNLOCK(kq); 1807 } 1808 } else { 1809 if (kq->kq_knhashmask == 0) { 1810 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE, 1811 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ? 1812 HASH_WAITOK : HASH_NOWAIT); 1813 if (tmp_knhash == NULL) 1814 return (ENOMEM); 1815 KQ_LOCK(kq); 1816 if ((kq->kq_state & KQ_CLOSING) != 0) { 1817 to_free = tmp_knhash; 1818 error = EBADF; 1819 } else if (kq->kq_knhashmask == 0) { 1820 kq->kq_knhash = tmp_knhash; 1821 kq->kq_knhashmask = tmp_knhashmask; 1822 } else { 1823 to_free = tmp_knhash; 1824 } 1825 KQ_UNLOCK(kq); 1826 } 1827 } 1828 free(to_free, M_KQUEUE); 1829 1830 KQ_NOTOWNED(kq); 1831 return (error); 1832 } 1833 1834 static void 1835 kqueue_task(void *arg, int pending) 1836 { 1837 struct kqueue *kq; 1838 int haskqglobal; 1839 1840 haskqglobal = 0; 1841 kq = arg; 1842 1843 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1844 KQ_LOCK(kq); 1845 1846 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1847 1848 kq->kq_state &= ~KQ_TASKSCHED; 1849 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1850 wakeup(&kq->kq_state); 1851 } 1852 KQ_UNLOCK(kq); 1853 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1854 } 1855 1856 /* 1857 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1858 * We treat KN_MARKER knotes as if they are in flux. 1859 */ 1860 static int 1861 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1862 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1863 { 1864 struct kevent *kevp; 1865 struct knote *kn, *marker; 1866 struct knlist *knl; 1867 sbintime_t asbt, rsbt; 1868 int count, error, haskqglobal, influx, nkev, touch; 1869 1870 count = maxevents; 1871 nkev = 0; 1872 error = 0; 1873 haskqglobal = 0; 1874 1875 if (maxevents == 0) 1876 goto done_nl; 1877 1878 rsbt = 0; 1879 if (tsp != NULL) { 1880 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1881 tsp->tv_nsec >= 1000000000) { 1882 error = EINVAL; 1883 goto done_nl; 1884 } 1885 if (timespecisset(tsp)) { 1886 if (tsp->tv_sec <= INT32_MAX) { 1887 rsbt = tstosbt(*tsp); 1888 if (TIMESEL(&asbt, rsbt)) 1889 asbt += tc_tick_sbt; 1890 if (asbt <= SBT_MAX - rsbt) 1891 asbt += rsbt; 1892 else 1893 asbt = 0; 1894 rsbt >>= tc_precexp; 1895 } else 1896 asbt = 0; 1897 } else 1898 asbt = -1; 1899 } else 1900 asbt = 0; 1901 marker = knote_alloc(M_WAITOK); 1902 marker->kn_status = KN_MARKER; 1903 KQ_LOCK(kq); 1904 1905 retry: 1906 kevp = keva; 1907 if (kq->kq_count == 0) { 1908 if (asbt == -1) { 1909 error = EWOULDBLOCK; 1910 } else { 1911 kq->kq_state |= KQ_SLEEP; 1912 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1913 "kqread", asbt, rsbt, C_ABSOLUTE); 1914 } 1915 if (error == 0) 1916 goto retry; 1917 /* don't restart after signals... */ 1918 if (error == ERESTART) 1919 error = EINTR; 1920 else if (error == EWOULDBLOCK) 1921 error = 0; 1922 goto done; 1923 } 1924 1925 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1926 influx = 0; 1927 while (count) { 1928 KQ_OWNED(kq); 1929 kn = TAILQ_FIRST(&kq->kq_head); 1930 1931 if ((kn->kn_status == KN_MARKER && kn != marker) || 1932 kn_in_flux(kn)) { 1933 if (influx) { 1934 influx = 0; 1935 KQ_FLUX_WAKEUP(kq); 1936 } 1937 kq->kq_state |= KQ_FLUXWAIT; 1938 error = msleep(kq, &kq->kq_lock, PSOCK, 1939 "kqflxwt", 0); 1940 continue; 1941 } 1942 1943 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1944 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1945 kn->kn_status &= ~KN_QUEUED; 1946 kq->kq_count--; 1947 continue; 1948 } 1949 if (kn == marker) { 1950 KQ_FLUX_WAKEUP(kq); 1951 if (count == maxevents) 1952 goto retry; 1953 goto done; 1954 } 1955 KASSERT(!kn_in_flux(kn), 1956 ("knote %p is unexpectedly in flux", kn)); 1957 1958 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1959 kn->kn_status &= ~KN_QUEUED; 1960 kn_enter_flux(kn); 1961 kq->kq_count--; 1962 KQ_UNLOCK(kq); 1963 /* 1964 * We don't need to lock the list since we've 1965 * marked it as in flux. 1966 */ 1967 knote_drop(kn, td); 1968 KQ_LOCK(kq); 1969 continue; 1970 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1971 kn->kn_status &= ~KN_QUEUED; 1972 kn_enter_flux(kn); 1973 kq->kq_count--; 1974 KQ_UNLOCK(kq); 1975 /* 1976 * We don't need to lock the list since we've 1977 * marked the knote as being in flux. 1978 */ 1979 *kevp = kn->kn_kevent; 1980 knote_drop(kn, td); 1981 KQ_LOCK(kq); 1982 kn = NULL; 1983 } else { 1984 kn->kn_status |= KN_SCAN; 1985 kn_enter_flux(kn); 1986 KQ_UNLOCK(kq); 1987 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1988 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1989 knl = kn_list_lock(kn); 1990 if (kn->kn_fop->f_event(kn, 0) == 0) { 1991 KQ_LOCK(kq); 1992 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1993 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1994 KN_SCAN); 1995 kn_leave_flux(kn); 1996 kq->kq_count--; 1997 kn_list_unlock(knl); 1998 influx = 1; 1999 continue; 2000 } 2001 touch = (!kn->kn_fop->f_isfd && 2002 kn->kn_fop->f_touch != NULL); 2003 if (touch) 2004 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 2005 else 2006 *kevp = kn->kn_kevent; 2007 KQ_LOCK(kq); 2008 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 2009 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 2010 /* 2011 * Manually clear knotes who weren't 2012 * 'touch'ed. 2013 */ 2014 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 2015 kn->kn_data = 0; 2016 kn->kn_fflags = 0; 2017 } 2018 if (kn->kn_flags & EV_DISPATCH) 2019 kn->kn_status |= KN_DISABLED; 2020 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 2021 kq->kq_count--; 2022 } else 2023 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2024 2025 kn->kn_status &= ~KN_SCAN; 2026 kn_leave_flux(kn); 2027 kn_list_unlock(knl); 2028 influx = 1; 2029 } 2030 2031 /* we are returning a copy to the user */ 2032 kevp++; 2033 nkev++; 2034 count--; 2035 2036 if (nkev == KQ_NEVENTS) { 2037 influx = 0; 2038 KQ_UNLOCK_FLUX(kq); 2039 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 2040 nkev = 0; 2041 kevp = keva; 2042 KQ_LOCK(kq); 2043 if (error) 2044 break; 2045 } 2046 } 2047 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 2048 done: 2049 KQ_OWNED(kq); 2050 KQ_UNLOCK_FLUX(kq); 2051 knote_free(marker); 2052 done_nl: 2053 KQ_NOTOWNED(kq); 2054 if (nkev != 0) 2055 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 2056 td->td_retval[0] = maxevents - count; 2057 return (error); 2058 } 2059 2060 /*ARGSUSED*/ 2061 static int 2062 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 2063 struct ucred *active_cred, struct thread *td) 2064 { 2065 /* 2066 * Enabling sigio causes two major problems: 2067 * 1) infinite recursion: 2068 * Synopsys: kevent is being used to track signals and have FIOASYNC 2069 * set. On receipt of a signal this will cause a kqueue to recurse 2070 * into itself over and over. Sending the sigio causes the kqueue 2071 * to become ready, which in turn posts sigio again, forever. 2072 * Solution: this can be solved by setting a flag in the kqueue that 2073 * we have a SIGIO in progress. 2074 * 2) locking problems: 2075 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 2076 * us above the proc and pgrp locks. 2077 * Solution: Post a signal using an async mechanism, being sure to 2078 * record a generation count in the delivery so that we do not deliver 2079 * a signal to the wrong process. 2080 * 2081 * Note, these two mechanisms are somewhat mutually exclusive! 2082 */ 2083 #if 0 2084 struct kqueue *kq; 2085 2086 kq = fp->f_data; 2087 switch (cmd) { 2088 case FIOASYNC: 2089 if (*(int *)data) { 2090 kq->kq_state |= KQ_ASYNC; 2091 } else { 2092 kq->kq_state &= ~KQ_ASYNC; 2093 } 2094 return (0); 2095 2096 case FIOSETOWN: 2097 return (fsetown(*(int *)data, &kq->kq_sigio)); 2098 2099 case FIOGETOWN: 2100 *(int *)data = fgetown(&kq->kq_sigio); 2101 return (0); 2102 } 2103 #endif 2104 2105 return (ENOTTY); 2106 } 2107 2108 /*ARGSUSED*/ 2109 static int 2110 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 2111 struct thread *td) 2112 { 2113 struct kqueue *kq; 2114 int revents = 0; 2115 int error; 2116 2117 if ((error = kqueue_acquire(fp, &kq))) 2118 return POLLERR; 2119 2120 KQ_LOCK(kq); 2121 if (events & (POLLIN | POLLRDNORM)) { 2122 if (kq->kq_count) { 2123 revents |= events & (POLLIN | POLLRDNORM); 2124 } else { 2125 selrecord(td, &kq->kq_sel); 2126 if (SEL_WAITING(&kq->kq_sel)) 2127 kq->kq_state |= KQ_SEL; 2128 } 2129 } 2130 kqueue_release(kq, 1); 2131 KQ_UNLOCK(kq); 2132 return (revents); 2133 } 2134 2135 /*ARGSUSED*/ 2136 static int 2137 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 2138 struct thread *td) 2139 { 2140 2141 bzero((void *)st, sizeof *st); 2142 /* 2143 * We no longer return kq_count because the unlocked value is useless. 2144 * If you spent all this time getting the count, why not spend your 2145 * syscall better by calling kevent? 2146 * 2147 * XXX - This is needed for libc_r. 2148 */ 2149 st->st_mode = S_IFIFO; 2150 return (0); 2151 } 2152 2153 static void 2154 kqueue_drain(struct kqueue *kq, struct thread *td) 2155 { 2156 struct knote *kn; 2157 int i; 2158 2159 KQ_LOCK(kq); 2160 2161 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 2162 ("kqueue already closing")); 2163 kq->kq_state |= KQ_CLOSING; 2164 if (kq->kq_refcnt > 1) 2165 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 2166 2167 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 2168 2169 KASSERT(knlist_empty(&kq->kq_sel.si_note), 2170 ("kqueue's knlist not empty")); 2171 2172 for (i = 0; i < kq->kq_knlistsize; i++) { 2173 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 2174 if (kn_in_flux(kn)) { 2175 kq->kq_state |= KQ_FLUXWAIT; 2176 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 2177 continue; 2178 } 2179 kn_enter_flux(kn); 2180 KQ_UNLOCK(kq); 2181 knote_drop(kn, td); 2182 KQ_LOCK(kq); 2183 } 2184 } 2185 if (kq->kq_knhashmask != 0) { 2186 for (i = 0; i <= kq->kq_knhashmask; i++) { 2187 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 2188 if (kn_in_flux(kn)) { 2189 kq->kq_state |= KQ_FLUXWAIT; 2190 msleep(kq, &kq->kq_lock, PSOCK, 2191 "kqclo2", 0); 2192 continue; 2193 } 2194 kn_enter_flux(kn); 2195 KQ_UNLOCK(kq); 2196 knote_drop(kn, td); 2197 KQ_LOCK(kq); 2198 } 2199 } 2200 } 2201 2202 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 2203 kq->kq_state |= KQ_TASKDRAIN; 2204 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 2205 } 2206 2207 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2208 selwakeuppri(&kq->kq_sel, PSOCK); 2209 if (!SEL_WAITING(&kq->kq_sel)) 2210 kq->kq_state &= ~KQ_SEL; 2211 } 2212 2213 KQ_UNLOCK(kq); 2214 } 2215 2216 static void 2217 kqueue_destroy(struct kqueue *kq) 2218 { 2219 2220 KASSERT(kq->kq_fdp == NULL, 2221 ("kqueue still attached to a file descriptor")); 2222 seldrain(&kq->kq_sel); 2223 knlist_destroy(&kq->kq_sel.si_note); 2224 mtx_destroy(&kq->kq_lock); 2225 2226 if (kq->kq_knhash != NULL) 2227 free(kq->kq_knhash, M_KQUEUE); 2228 if (kq->kq_knlist != NULL) 2229 free(kq->kq_knlist, M_KQUEUE); 2230 2231 funsetown(&kq->kq_sigio); 2232 } 2233 2234 /*ARGSUSED*/ 2235 static int 2236 kqueue_close(struct file *fp, struct thread *td) 2237 { 2238 struct kqueue *kq = fp->f_data; 2239 struct filedesc *fdp; 2240 int error; 2241 int filedesc_unlock; 2242 2243 if ((error = kqueue_acquire(fp, &kq))) 2244 return error; 2245 kqueue_drain(kq, td); 2246 2247 /* 2248 * We could be called due to the knote_drop() doing fdrop(), 2249 * called from kqueue_register(). In this case the global 2250 * lock is owned, and filedesc sx is locked before, to not 2251 * take the sleepable lock after non-sleepable. 2252 */ 2253 fdp = kq->kq_fdp; 2254 kq->kq_fdp = NULL; 2255 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 2256 FILEDESC_XLOCK(fdp); 2257 filedesc_unlock = 1; 2258 } else 2259 filedesc_unlock = 0; 2260 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 2261 if (filedesc_unlock) 2262 FILEDESC_XUNLOCK(fdp); 2263 2264 kqueue_destroy(kq); 2265 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 2266 crfree(kq->kq_cred); 2267 free(kq, M_KQUEUE); 2268 fp->f_data = NULL; 2269 2270 return (0); 2271 } 2272 2273 static int 2274 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2275 { 2276 2277 kif->kf_type = KF_TYPE_KQUEUE; 2278 return (0); 2279 } 2280 2281 static void 2282 kqueue_wakeup(struct kqueue *kq) 2283 { 2284 KQ_OWNED(kq); 2285 2286 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2287 kq->kq_state &= ~KQ_SLEEP; 2288 wakeup(kq); 2289 } 2290 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2291 selwakeuppri(&kq->kq_sel, PSOCK); 2292 if (!SEL_WAITING(&kq->kq_sel)) 2293 kq->kq_state &= ~KQ_SEL; 2294 } 2295 if (!knlist_empty(&kq->kq_sel.si_note)) 2296 kqueue_schedtask(kq); 2297 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2298 pgsigio(&kq->kq_sigio, SIGIO, 0); 2299 } 2300 } 2301 2302 /* 2303 * Walk down a list of knotes, activating them if their event has triggered. 2304 * 2305 * There is a possibility to optimize in the case of one kq watching another. 2306 * Instead of scheduling a task to wake it up, you could pass enough state 2307 * down the chain to make up the parent kqueue. Make this code functional 2308 * first. 2309 */ 2310 void 2311 knote(struct knlist *list, long hint, int lockflags) 2312 { 2313 struct kqueue *kq; 2314 struct knote *kn, *tkn; 2315 int error; 2316 2317 if (list == NULL) 2318 return; 2319 2320 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2321 2322 if ((lockflags & KNF_LISTLOCKED) == 0) 2323 list->kl_lock(list->kl_lockarg); 2324 2325 /* 2326 * If we unlock the list lock (and enter influx), we can 2327 * eliminate the kqueue scheduling, but this will introduce 2328 * four lock/unlock's for each knote to test. Also, marker 2329 * would be needed to keep iteration position, since filters 2330 * or other threads could remove events. 2331 */ 2332 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2333 kq = kn->kn_kq; 2334 KQ_LOCK(kq); 2335 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2336 /* 2337 * Do not process the influx notes, except for 2338 * the influx coming from the kq unlock in the 2339 * kqueue_scan(). In the later case, we do 2340 * not interfere with the scan, since the code 2341 * fragment in kqueue_scan() locks the knlist, 2342 * and cannot proceed until we finished. 2343 */ 2344 KQ_UNLOCK(kq); 2345 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2346 kn_enter_flux(kn); 2347 KQ_UNLOCK(kq); 2348 error = kn->kn_fop->f_event(kn, hint); 2349 KQ_LOCK(kq); 2350 kn_leave_flux(kn); 2351 if (error) 2352 KNOTE_ACTIVATE(kn, 1); 2353 KQ_UNLOCK_FLUX(kq); 2354 } else { 2355 if (kn->kn_fop->f_event(kn, hint)) 2356 KNOTE_ACTIVATE(kn, 1); 2357 KQ_UNLOCK(kq); 2358 } 2359 } 2360 if ((lockflags & KNF_LISTLOCKED) == 0) 2361 list->kl_unlock(list->kl_lockarg); 2362 } 2363 2364 /* 2365 * add a knote to a knlist 2366 */ 2367 void 2368 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2369 { 2370 2371 KNL_ASSERT_LOCK(knl, islocked); 2372 KQ_NOTOWNED(kn->kn_kq); 2373 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2374 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2375 ("knote %p was not detached", kn)); 2376 if (!islocked) 2377 knl->kl_lock(knl->kl_lockarg); 2378 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2379 if (!islocked) 2380 knl->kl_unlock(knl->kl_lockarg); 2381 KQ_LOCK(kn->kn_kq); 2382 kn->kn_knlist = knl; 2383 kn->kn_status &= ~KN_DETACHED; 2384 KQ_UNLOCK(kn->kn_kq); 2385 } 2386 2387 static void 2388 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2389 int kqislocked) 2390 { 2391 2392 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2393 KNL_ASSERT_LOCK(knl, knlislocked); 2394 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2395 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2396 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2397 ("knote %p was already detached", kn)); 2398 if (!knlislocked) 2399 knl->kl_lock(knl->kl_lockarg); 2400 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2401 kn->kn_knlist = NULL; 2402 if (!knlislocked) 2403 kn_list_unlock(knl); 2404 if (!kqislocked) 2405 KQ_LOCK(kn->kn_kq); 2406 kn->kn_status |= KN_DETACHED; 2407 if (!kqislocked) 2408 KQ_UNLOCK(kn->kn_kq); 2409 } 2410 2411 /* 2412 * remove knote from the specified knlist 2413 */ 2414 void 2415 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2416 { 2417 2418 knlist_remove_kq(knl, kn, islocked, 0); 2419 } 2420 2421 int 2422 knlist_empty(struct knlist *knl) 2423 { 2424 2425 KNL_ASSERT_LOCKED(knl); 2426 return (SLIST_EMPTY(&knl->kl_list)); 2427 } 2428 2429 static struct mtx knlist_lock; 2430 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2431 MTX_DEF); 2432 static void knlist_mtx_lock(void *arg); 2433 static void knlist_mtx_unlock(void *arg); 2434 2435 static void 2436 knlist_mtx_lock(void *arg) 2437 { 2438 2439 mtx_lock((struct mtx *)arg); 2440 } 2441 2442 static void 2443 knlist_mtx_unlock(void *arg) 2444 { 2445 2446 mtx_unlock((struct mtx *)arg); 2447 } 2448 2449 static void 2450 knlist_mtx_assert_lock(void *arg, int what) 2451 { 2452 2453 if (what == LA_LOCKED) 2454 mtx_assert((struct mtx *)arg, MA_OWNED); 2455 else 2456 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2457 } 2458 2459 static void 2460 knlist_rw_rlock(void *arg) 2461 { 2462 2463 rw_rlock((struct rwlock *)arg); 2464 } 2465 2466 static void 2467 knlist_rw_runlock(void *arg) 2468 { 2469 2470 rw_runlock((struct rwlock *)arg); 2471 } 2472 2473 static void 2474 knlist_rw_assert_lock(void *arg, int what) 2475 { 2476 2477 if (what == LA_LOCKED) 2478 rw_assert((struct rwlock *)arg, RA_LOCKED); 2479 else 2480 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2481 } 2482 2483 void 2484 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2485 void (*kl_unlock)(void *), 2486 void (*kl_assert_lock)(void *, int)) 2487 { 2488 2489 if (lock == NULL) 2490 knl->kl_lockarg = &knlist_lock; 2491 else 2492 knl->kl_lockarg = lock; 2493 2494 if (kl_lock == NULL) 2495 knl->kl_lock = knlist_mtx_lock; 2496 else 2497 knl->kl_lock = kl_lock; 2498 if (kl_unlock == NULL) 2499 knl->kl_unlock = knlist_mtx_unlock; 2500 else 2501 knl->kl_unlock = kl_unlock; 2502 if (kl_assert_lock == NULL) 2503 knl->kl_assert_lock = knlist_mtx_assert_lock; 2504 else 2505 knl->kl_assert_lock = kl_assert_lock; 2506 2507 knl->kl_autodestroy = 0; 2508 SLIST_INIT(&knl->kl_list); 2509 } 2510 2511 void 2512 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2513 { 2514 2515 knlist_init(knl, lock, NULL, NULL, NULL); 2516 } 2517 2518 struct knlist * 2519 knlist_alloc(struct mtx *lock) 2520 { 2521 struct knlist *knl; 2522 2523 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2524 knlist_init_mtx(knl, lock); 2525 return (knl); 2526 } 2527 2528 void 2529 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2530 { 2531 2532 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2533 knlist_rw_assert_lock); 2534 } 2535 2536 void 2537 knlist_destroy(struct knlist *knl) 2538 { 2539 2540 KASSERT(KNLIST_EMPTY(knl), 2541 ("destroying knlist %p with knotes on it", knl)); 2542 } 2543 2544 void 2545 knlist_detach(struct knlist *knl) 2546 { 2547 2548 KNL_ASSERT_LOCKED(knl); 2549 knl->kl_autodestroy = 1; 2550 if (knlist_empty(knl)) { 2551 knlist_destroy(knl); 2552 free(knl, M_KQUEUE); 2553 } 2554 } 2555 2556 /* 2557 * Even if we are locked, we may need to drop the lock to allow any influx 2558 * knotes time to "settle". 2559 */ 2560 void 2561 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2562 { 2563 struct knote *kn, *kn2; 2564 struct kqueue *kq; 2565 2566 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2567 if (islocked) 2568 KNL_ASSERT_LOCKED(knl); 2569 else { 2570 KNL_ASSERT_UNLOCKED(knl); 2571 again: /* need to reacquire lock since we have dropped it */ 2572 knl->kl_lock(knl->kl_lockarg); 2573 } 2574 2575 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2576 kq = kn->kn_kq; 2577 KQ_LOCK(kq); 2578 if (kn_in_flux(kn)) { 2579 KQ_UNLOCK(kq); 2580 continue; 2581 } 2582 knlist_remove_kq(knl, kn, 1, 1); 2583 if (killkn) { 2584 kn_enter_flux(kn); 2585 KQ_UNLOCK(kq); 2586 knote_drop_detached(kn, td); 2587 } else { 2588 /* Make sure cleared knotes disappear soon */ 2589 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2590 KQ_UNLOCK(kq); 2591 } 2592 kq = NULL; 2593 } 2594 2595 if (!SLIST_EMPTY(&knl->kl_list)) { 2596 /* there are still in flux knotes remaining */ 2597 kn = SLIST_FIRST(&knl->kl_list); 2598 kq = kn->kn_kq; 2599 KQ_LOCK(kq); 2600 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2601 knl->kl_unlock(knl->kl_lockarg); 2602 kq->kq_state |= KQ_FLUXWAIT; 2603 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2604 kq = NULL; 2605 goto again; 2606 } 2607 2608 if (islocked) 2609 KNL_ASSERT_LOCKED(knl); 2610 else { 2611 knl->kl_unlock(knl->kl_lockarg); 2612 KNL_ASSERT_UNLOCKED(knl); 2613 } 2614 } 2615 2616 /* 2617 * Remove all knotes referencing a specified fd must be called with FILEDESC 2618 * lock. This prevents a race where a new fd comes along and occupies the 2619 * entry and we attach a knote to the fd. 2620 */ 2621 void 2622 knote_fdclose(struct thread *td, int fd) 2623 { 2624 struct filedesc *fdp = td->td_proc->p_fd; 2625 struct kqueue *kq; 2626 struct knote *kn; 2627 int influx; 2628 2629 FILEDESC_XLOCK_ASSERT(fdp); 2630 2631 /* 2632 * We shouldn't have to worry about new kevents appearing on fd 2633 * since filedesc is locked. 2634 */ 2635 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2636 KQ_LOCK(kq); 2637 2638 again: 2639 influx = 0; 2640 while (kq->kq_knlistsize > fd && 2641 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2642 if (kn_in_flux(kn)) { 2643 /* someone else might be waiting on our knote */ 2644 if (influx) 2645 wakeup(kq); 2646 kq->kq_state |= KQ_FLUXWAIT; 2647 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2648 goto again; 2649 } 2650 kn_enter_flux(kn); 2651 KQ_UNLOCK(kq); 2652 influx = 1; 2653 knote_drop(kn, td); 2654 KQ_LOCK(kq); 2655 } 2656 KQ_UNLOCK_FLUX(kq); 2657 } 2658 } 2659 2660 static int 2661 knote_attach(struct knote *kn, struct kqueue *kq) 2662 { 2663 struct klist *list; 2664 2665 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2666 KQ_OWNED(kq); 2667 2668 if ((kq->kq_state & KQ_CLOSING) != 0) 2669 return (EBADF); 2670 if (kn->kn_fop->f_isfd) { 2671 if (kn->kn_id >= kq->kq_knlistsize) 2672 return (ENOMEM); 2673 list = &kq->kq_knlist[kn->kn_id]; 2674 } else { 2675 if (kq->kq_knhash == NULL) 2676 return (ENOMEM); 2677 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2678 } 2679 SLIST_INSERT_HEAD(list, kn, kn_link); 2680 return (0); 2681 } 2682 2683 static void 2684 knote_drop(struct knote *kn, struct thread *td) 2685 { 2686 2687 if ((kn->kn_status & KN_DETACHED) == 0) 2688 kn->kn_fop->f_detach(kn); 2689 knote_drop_detached(kn, td); 2690 } 2691 2692 static void 2693 knote_drop_detached(struct knote *kn, struct thread *td) 2694 { 2695 struct kqueue *kq; 2696 struct klist *list; 2697 2698 kq = kn->kn_kq; 2699 2700 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2701 ("knote %p still attached", kn)); 2702 KQ_NOTOWNED(kq); 2703 2704 KQ_LOCK(kq); 2705 KASSERT(kn->kn_influx == 1, 2706 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2707 2708 if (kn->kn_fop->f_isfd) 2709 list = &kq->kq_knlist[kn->kn_id]; 2710 else 2711 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2712 2713 if (!SLIST_EMPTY(list)) 2714 SLIST_REMOVE(list, kn, knote, kn_link); 2715 if (kn->kn_status & KN_QUEUED) 2716 knote_dequeue(kn); 2717 KQ_UNLOCK_FLUX(kq); 2718 2719 if (kn->kn_fop->f_isfd) { 2720 fdrop(kn->kn_fp, td); 2721 kn->kn_fp = NULL; 2722 } 2723 kqueue_fo_release(kn->kn_kevent.filter); 2724 kn->kn_fop = NULL; 2725 knote_free(kn); 2726 } 2727 2728 static void 2729 knote_enqueue(struct knote *kn) 2730 { 2731 struct kqueue *kq = kn->kn_kq; 2732 2733 KQ_OWNED(kn->kn_kq); 2734 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2735 2736 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2737 kn->kn_status |= KN_QUEUED; 2738 kq->kq_count++; 2739 kqueue_wakeup(kq); 2740 } 2741 2742 static void 2743 knote_dequeue(struct knote *kn) 2744 { 2745 struct kqueue *kq = kn->kn_kq; 2746 2747 KQ_OWNED(kn->kn_kq); 2748 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2749 2750 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2751 kn->kn_status &= ~KN_QUEUED; 2752 kq->kq_count--; 2753 } 2754 2755 static void 2756 knote_init(void) 2757 { 2758 2759 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2760 NULL, NULL, UMA_ALIGN_PTR, 0); 2761 } 2762 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2763 2764 static struct knote * 2765 knote_alloc(int mflag) 2766 { 2767 2768 return (uma_zalloc(knote_zone, mflag | M_ZERO)); 2769 } 2770 2771 static void 2772 knote_free(struct knote *kn) 2773 { 2774 2775 uma_zfree(knote_zone, kn); 2776 } 2777 2778 /* 2779 * Register the kev w/ the kq specified by fd. 2780 */ 2781 int 2782 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag) 2783 { 2784 struct kqueue *kq; 2785 struct file *fp; 2786 cap_rights_t rights; 2787 int error; 2788 2789 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE), 2790 &fp); 2791 if (error != 0) 2792 return (error); 2793 if ((error = kqueue_acquire(fp, &kq)) != 0) 2794 goto noacquire; 2795 2796 error = kqueue_register(kq, kev, td, mflag); 2797 kqueue_release(kq, 0); 2798 2799 noacquire: 2800 fdrop(fp, td); 2801 return (error); 2802 } 2803