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 __exclusive_cache_line kq_ncallouts; 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 int flags; 684 TAILQ_ENTRY(kq_timer_cb_data) link; 685 sbintime_t next; /* next timer event fires at */ 686 sbintime_t to; /* precalculated timer period, 0 for abs */ 687 }; 688 689 #define KQ_TIMER_CB_ENQUEUED 0x01 690 691 static void 692 kqtimer_sched_callout(struct kq_timer_cb_data *kc) 693 { 694 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kc->kn, 695 kc->cpuid, C_ABSOLUTE); 696 } 697 698 void 699 kqtimer_proc_continue(struct proc *p) 700 { 701 struct kq_timer_cb_data *kc, *kc1; 702 struct bintime bt; 703 sbintime_t now; 704 705 PROC_LOCK_ASSERT(p, MA_OWNED); 706 707 getboottimebin(&bt); 708 now = bttosbt(bt); 709 710 TAILQ_FOREACH_SAFE(kc, &p->p_kqtim_stop, link, kc1) { 711 TAILQ_REMOVE(&p->p_kqtim_stop, kc, link); 712 kc->flags &= ~KQ_TIMER_CB_ENQUEUED; 713 if (kc->next <= now) 714 filt_timerexpire_l(kc->kn, true); 715 else 716 kqtimer_sched_callout(kc); 717 } 718 } 719 720 static void 721 filt_timerexpire_l(struct knote *kn, bool proc_locked) 722 { 723 struct kq_timer_cb_data *kc; 724 struct proc *p; 725 uint64_t delta; 726 sbintime_t now; 727 728 kc = kn->kn_ptr.p_v; 729 730 if ((kn->kn_flags & EV_ONESHOT) != 0 || kc->to == 0) { 731 kn->kn_data++; 732 KNOTE_ACTIVATE(kn, 0); 733 return; 734 } 735 736 now = sbinuptime(); 737 if (now >= kc->next) { 738 delta = (now - kc->next) / kc->to; 739 if (delta == 0) 740 delta = 1; 741 kn->kn_data += delta; 742 kc->next += (delta + 1) * kc->to; 743 if (now >= kc->next) /* overflow */ 744 kc->next = now + kc->to; 745 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 746 } 747 748 /* 749 * Initial check for stopped kc->p is racy. It is fine to 750 * miss the set of the stop flags, at worst we would schedule 751 * one more callout. On the other hand, it is not fine to not 752 * schedule when we we missed clearing of the flags, we 753 * recheck them under the lock and observe consistent state. 754 */ 755 p = kc->p; 756 if (P_SHOULDSTOP(p) || P_KILLED(p)) { 757 if (!proc_locked) 758 PROC_LOCK(p); 759 if (P_SHOULDSTOP(p) || P_KILLED(p)) { 760 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) == 0) { 761 kc->flags |= KQ_TIMER_CB_ENQUEUED; 762 TAILQ_INSERT_TAIL(&p->p_kqtim_stop, kc, link); 763 } 764 if (!proc_locked) 765 PROC_UNLOCK(p); 766 return; 767 } 768 if (!proc_locked) 769 PROC_UNLOCK(p); 770 } 771 kqtimer_sched_callout(kc); 772 } 773 774 static void 775 filt_timerexpire(void *knx) 776 { 777 filt_timerexpire_l(knx, false); 778 } 779 780 /* 781 * data contains amount of time to sleep 782 */ 783 static int 784 filt_timervalidate(struct knote *kn, sbintime_t *to) 785 { 786 struct bintime bt; 787 sbintime_t sbt; 788 789 if (kn->kn_sdata < 0) 790 return (EINVAL); 791 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 792 kn->kn_sdata = 1; 793 /* 794 * The only fflags values supported are the timer unit 795 * (precision) and the absolute time indicator. 796 */ 797 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0) 798 return (EINVAL); 799 800 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 801 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 802 getboottimebin(&bt); 803 sbt = bttosbt(bt); 804 *to -= sbt; 805 } 806 if (*to < 0) 807 return (EINVAL); 808 return (0); 809 } 810 811 static int 812 filt_timerattach(struct knote *kn) 813 { 814 struct kq_timer_cb_data *kc; 815 sbintime_t to; 816 int error; 817 818 error = filt_timervalidate(kn, &to); 819 if (error != 0) 820 return (error); 821 822 if (atomic_fetchadd_int(&kq_ncallouts, 1) + 1 > kq_calloutmax) { 823 atomic_subtract_int(&kq_ncallouts, 1); 824 return (ENOMEM); 825 } 826 827 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0) 828 kn->kn_flags |= EV_CLEAR; /* automatically set */ 829 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 830 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 831 kc->kn = kn; 832 kc->p = curproc; 833 kc->cpuid = PCPU_GET(cpuid); 834 kc->flags = 0; 835 callout_init(&kc->c, 1); 836 filt_timerstart(kn, to); 837 838 return (0); 839 } 840 841 static void 842 filt_timerstart(struct knote *kn, sbintime_t to) 843 { 844 struct kq_timer_cb_data *kc; 845 846 kc = kn->kn_ptr.p_v; 847 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 848 kc->next = to; 849 kc->to = 0; 850 } else { 851 kc->next = to + sbinuptime(); 852 kc->to = to; 853 } 854 kqtimer_sched_callout(kc); 855 } 856 857 static void 858 filt_timerdetach(struct knote *kn) 859 { 860 struct kq_timer_cb_data *kc; 861 unsigned int old __unused; 862 bool pending; 863 864 kc = kn->kn_ptr.p_v; 865 do { 866 callout_drain(&kc->c); 867 868 /* 869 * kqtimer_proc_continue() might have rescheduled this callout. 870 * Double-check, using the process mutex as an interlock. 871 */ 872 PROC_LOCK(kc->p); 873 if ((kc->flags & KQ_TIMER_CB_ENQUEUED) != 0) { 874 kc->flags &= ~KQ_TIMER_CB_ENQUEUED; 875 TAILQ_REMOVE(&kc->p->p_kqtim_stop, kc, link); 876 } 877 pending = callout_pending(&kc->c); 878 PROC_UNLOCK(kc->p); 879 } while (pending); 880 free(kc, M_KQUEUE); 881 old = atomic_fetchadd_int(&kq_ncallouts, -1); 882 KASSERT(old > 0, ("Number of callouts cannot become negative")); 883 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 884 } 885 886 static void 887 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type) 888 { 889 struct kq_timer_cb_data *kc; 890 struct kqueue *kq; 891 sbintime_t to; 892 int error; 893 894 switch (type) { 895 case EVENT_REGISTER: 896 /* Handle re-added timers that update data/fflags */ 897 if (kev->flags & EV_ADD) { 898 kc = kn->kn_ptr.p_v; 899 900 /* Drain any existing callout. */ 901 callout_drain(&kc->c); 902 903 /* Throw away any existing undelivered record 904 * of the timer expiration. This is done under 905 * the presumption that if a process is 906 * re-adding this timer with new parameters, 907 * it is no longer interested in what may have 908 * happened under the old parameters. If it is 909 * interested, it can wait for the expiration, 910 * delete the old timer definition, and then 911 * add the new one. 912 * 913 * This has to be done while the kq is locked: 914 * - if enqueued, dequeue 915 * - make it no longer active 916 * - clear the count of expiration events 917 */ 918 kq = kn->kn_kq; 919 KQ_LOCK(kq); 920 if (kn->kn_status & KN_QUEUED) 921 knote_dequeue(kn); 922 923 kn->kn_status &= ~KN_ACTIVE; 924 kn->kn_data = 0; 925 KQ_UNLOCK(kq); 926 927 /* Reschedule timer based on new data/fflags */ 928 kn->kn_sfflags = kev->fflags; 929 kn->kn_sdata = kev->data; 930 error = filt_timervalidate(kn, &to); 931 if (error != 0) { 932 kn->kn_flags |= EV_ERROR; 933 kn->kn_data = error; 934 } else 935 filt_timerstart(kn, to); 936 } 937 break; 938 939 case EVENT_PROCESS: 940 *kev = kn->kn_kevent; 941 if (kn->kn_flags & EV_CLEAR) { 942 kn->kn_data = 0; 943 kn->kn_fflags = 0; 944 } 945 break; 946 947 default: 948 panic("filt_timertouch() - invalid type (%ld)", type); 949 break; 950 } 951 } 952 953 static int 954 filt_timer(struct knote *kn, long hint) 955 { 956 957 return (kn->kn_data != 0); 958 } 959 960 static int 961 filt_userattach(struct knote *kn) 962 { 963 964 /* 965 * EVFILT_USER knotes are not attached to anything in the kernel. 966 */ 967 kn->kn_hook = NULL; 968 if (kn->kn_fflags & NOTE_TRIGGER) 969 kn->kn_hookid = 1; 970 else 971 kn->kn_hookid = 0; 972 return (0); 973 } 974 975 static void 976 filt_userdetach(__unused struct knote *kn) 977 { 978 979 /* 980 * EVFILT_USER knotes are not attached to anything in the kernel. 981 */ 982 } 983 984 static int 985 filt_user(struct knote *kn, __unused long hint) 986 { 987 988 return (kn->kn_hookid); 989 } 990 991 static void 992 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 993 { 994 u_int ffctrl; 995 996 switch (type) { 997 case EVENT_REGISTER: 998 if (kev->fflags & NOTE_TRIGGER) 999 kn->kn_hookid = 1; 1000 1001 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 1002 kev->fflags &= NOTE_FFLAGSMASK; 1003 switch (ffctrl) { 1004 case NOTE_FFNOP: 1005 break; 1006 1007 case NOTE_FFAND: 1008 kn->kn_sfflags &= kev->fflags; 1009 break; 1010 1011 case NOTE_FFOR: 1012 kn->kn_sfflags |= kev->fflags; 1013 break; 1014 1015 case NOTE_FFCOPY: 1016 kn->kn_sfflags = kev->fflags; 1017 break; 1018 1019 default: 1020 /* XXX Return error? */ 1021 break; 1022 } 1023 kn->kn_sdata = kev->data; 1024 if (kev->flags & EV_CLEAR) { 1025 kn->kn_hookid = 0; 1026 kn->kn_data = 0; 1027 kn->kn_fflags = 0; 1028 } 1029 break; 1030 1031 case EVENT_PROCESS: 1032 *kev = kn->kn_kevent; 1033 kev->fflags = kn->kn_sfflags; 1034 kev->data = kn->kn_sdata; 1035 if (kn->kn_flags & EV_CLEAR) { 1036 kn->kn_hookid = 0; 1037 kn->kn_data = 0; 1038 kn->kn_fflags = 0; 1039 } 1040 break; 1041 1042 default: 1043 panic("filt_usertouch() - invalid type (%ld)", type); 1044 break; 1045 } 1046 } 1047 1048 int 1049 sys_kqueue(struct thread *td, struct kqueue_args *uap) 1050 { 1051 1052 return (kern_kqueue(td, 0, NULL)); 1053 } 1054 1055 static void 1056 kqueue_init(struct kqueue *kq) 1057 { 1058 1059 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 1060 TAILQ_INIT(&kq->kq_head); 1061 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 1062 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 1063 } 1064 1065 int 1066 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 1067 { 1068 struct filedesc *fdp; 1069 struct kqueue *kq; 1070 struct file *fp; 1071 struct ucred *cred; 1072 int fd, error; 1073 1074 fdp = td->td_proc->p_fd; 1075 cred = td->td_ucred; 1076 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 1077 return (ENOMEM); 1078 1079 error = falloc_caps(td, &fp, &fd, flags, fcaps); 1080 if (error != 0) { 1081 chgkqcnt(cred->cr_ruidinfo, -1, 0); 1082 return (error); 1083 } 1084 1085 /* An extra reference on `fp' has been held for us by falloc(). */ 1086 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 1087 kqueue_init(kq); 1088 kq->kq_fdp = fdp; 1089 kq->kq_cred = crhold(cred); 1090 1091 FILEDESC_XLOCK(fdp); 1092 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 1093 FILEDESC_XUNLOCK(fdp); 1094 1095 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 1096 fdrop(fp, td); 1097 1098 td->td_retval[0] = fd; 1099 return (0); 1100 } 1101 1102 struct g_kevent_args { 1103 int fd; 1104 void *changelist; 1105 int nchanges; 1106 void *eventlist; 1107 int nevents; 1108 const struct timespec *timeout; 1109 }; 1110 1111 int 1112 sys_kevent(struct thread *td, struct kevent_args *uap) 1113 { 1114 struct kevent_copyops k_ops = { 1115 .arg = uap, 1116 .k_copyout = kevent_copyout, 1117 .k_copyin = kevent_copyin, 1118 .kevent_size = sizeof(struct kevent), 1119 }; 1120 struct g_kevent_args gk_args = { 1121 .fd = uap->fd, 1122 .changelist = uap->changelist, 1123 .nchanges = uap->nchanges, 1124 .eventlist = uap->eventlist, 1125 .nevents = uap->nevents, 1126 .timeout = uap->timeout, 1127 }; 1128 1129 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent")); 1130 } 1131 1132 static int 1133 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap, 1134 struct kevent_copyops *k_ops, const char *struct_name) 1135 { 1136 struct timespec ts, *tsp; 1137 #ifdef KTRACE 1138 struct kevent *eventlist = uap->eventlist; 1139 #endif 1140 int error; 1141 1142 if (uap->timeout != NULL) { 1143 error = copyin(uap->timeout, &ts, sizeof(ts)); 1144 if (error) 1145 return (error); 1146 tsp = &ts; 1147 } else 1148 tsp = NULL; 1149 1150 #ifdef KTRACE 1151 if (KTRPOINT(td, KTR_STRUCT_ARRAY)) 1152 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist, 1153 uap->nchanges, k_ops->kevent_size); 1154 #endif 1155 1156 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 1157 k_ops, tsp); 1158 1159 #ifdef KTRACE 1160 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY)) 1161 ktrstructarray(struct_name, UIO_USERSPACE, eventlist, 1162 td->td_retval[0], k_ops->kevent_size); 1163 #endif 1164 1165 return (error); 1166 } 1167 1168 /* 1169 * Copy 'count' items into the destination list pointed to by uap->eventlist. 1170 */ 1171 static int 1172 kevent_copyout(void *arg, struct kevent *kevp, int count) 1173 { 1174 struct kevent_args *uap; 1175 int error; 1176 1177 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1178 uap = (struct kevent_args *)arg; 1179 1180 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 1181 if (error == 0) 1182 uap->eventlist += count; 1183 return (error); 1184 } 1185 1186 /* 1187 * Copy 'count' items from the list pointed to by uap->changelist. 1188 */ 1189 static int 1190 kevent_copyin(void *arg, struct kevent *kevp, int count) 1191 { 1192 struct kevent_args *uap; 1193 int error; 1194 1195 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1196 uap = (struct kevent_args *)arg; 1197 1198 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 1199 if (error == 0) 1200 uap->changelist += count; 1201 return (error); 1202 } 1203 1204 #ifdef COMPAT_FREEBSD11 1205 static int 1206 kevent11_copyout(void *arg, struct kevent *kevp, int count) 1207 { 1208 struct freebsd11_kevent_args *uap; 1209 struct kevent_freebsd11 kev11; 1210 int error, i; 1211 1212 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1213 uap = (struct freebsd11_kevent_args *)arg; 1214 1215 for (i = 0; i < count; i++) { 1216 kev11.ident = kevp->ident; 1217 kev11.filter = kevp->filter; 1218 kev11.flags = kevp->flags; 1219 kev11.fflags = kevp->fflags; 1220 kev11.data = kevp->data; 1221 kev11.udata = kevp->udata; 1222 error = copyout(&kev11, uap->eventlist, sizeof(kev11)); 1223 if (error != 0) 1224 break; 1225 uap->eventlist++; 1226 kevp++; 1227 } 1228 return (error); 1229 } 1230 1231 /* 1232 * Copy 'count' items from the list pointed to by uap->changelist. 1233 */ 1234 static int 1235 kevent11_copyin(void *arg, struct kevent *kevp, int count) 1236 { 1237 struct freebsd11_kevent_args *uap; 1238 struct kevent_freebsd11 kev11; 1239 int error, i; 1240 1241 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1242 uap = (struct freebsd11_kevent_args *)arg; 1243 1244 for (i = 0; i < count; i++) { 1245 error = copyin(uap->changelist, &kev11, sizeof(kev11)); 1246 if (error != 0) 1247 break; 1248 kevp->ident = kev11.ident; 1249 kevp->filter = kev11.filter; 1250 kevp->flags = kev11.flags; 1251 kevp->fflags = kev11.fflags; 1252 kevp->data = (uintptr_t)kev11.data; 1253 kevp->udata = kev11.udata; 1254 bzero(&kevp->ext, sizeof(kevp->ext)); 1255 uap->changelist++; 1256 kevp++; 1257 } 1258 return (error); 1259 } 1260 1261 int 1262 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap) 1263 { 1264 struct kevent_copyops k_ops = { 1265 .arg = uap, 1266 .k_copyout = kevent11_copyout, 1267 .k_copyin = kevent11_copyin, 1268 .kevent_size = sizeof(struct kevent_freebsd11), 1269 }; 1270 struct g_kevent_args gk_args = { 1271 .fd = uap->fd, 1272 .changelist = uap->changelist, 1273 .nchanges = uap->nchanges, 1274 .eventlist = uap->eventlist, 1275 .nevents = uap->nevents, 1276 .timeout = uap->timeout, 1277 }; 1278 1279 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11")); 1280 } 1281 #endif 1282 1283 int 1284 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1285 struct kevent_copyops *k_ops, const struct timespec *timeout) 1286 { 1287 cap_rights_t rights; 1288 struct file *fp; 1289 int error; 1290 1291 cap_rights_init_zero(&rights); 1292 if (nchanges > 0) 1293 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE); 1294 if (nevents > 0) 1295 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT); 1296 error = fget(td, fd, &rights, &fp); 1297 if (error != 0) 1298 return (error); 1299 1300 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1301 fdrop(fp, td); 1302 1303 return (error); 1304 } 1305 1306 static int 1307 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1308 struct kevent_copyops *k_ops, const struct timespec *timeout) 1309 { 1310 struct kevent keva[KQ_NEVENTS]; 1311 struct kevent *kevp, *changes; 1312 int i, n, nerrors, error; 1313 1314 if (nchanges < 0) 1315 return (EINVAL); 1316 1317 nerrors = 0; 1318 while (nchanges > 0) { 1319 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1320 error = k_ops->k_copyin(k_ops->arg, keva, n); 1321 if (error) 1322 return (error); 1323 changes = keva; 1324 for (i = 0; i < n; i++) { 1325 kevp = &changes[i]; 1326 if (!kevp->filter) 1327 continue; 1328 kevp->flags &= ~EV_SYSFLAGS; 1329 error = kqueue_register(kq, kevp, td, M_WAITOK); 1330 if (error || (kevp->flags & EV_RECEIPT)) { 1331 if (nevents == 0) 1332 return (error); 1333 kevp->flags = EV_ERROR; 1334 kevp->data = error; 1335 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1336 nevents--; 1337 nerrors++; 1338 } 1339 } 1340 nchanges -= n; 1341 } 1342 if (nerrors) { 1343 td->td_retval[0] = nerrors; 1344 return (0); 1345 } 1346 1347 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1348 } 1349 1350 int 1351 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1352 struct kevent_copyops *k_ops, const struct timespec *timeout) 1353 { 1354 struct kqueue *kq; 1355 int error; 1356 1357 error = kqueue_acquire(fp, &kq); 1358 if (error != 0) 1359 return (error); 1360 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1361 kqueue_release(kq, 0); 1362 return (error); 1363 } 1364 1365 /* 1366 * Performs a kevent() call on a temporarily created kqueue. This can be 1367 * used to perform one-shot polling, similar to poll() and select(). 1368 */ 1369 int 1370 kern_kevent_anonymous(struct thread *td, int nevents, 1371 struct kevent_copyops *k_ops) 1372 { 1373 struct kqueue kq = {}; 1374 int error; 1375 1376 kqueue_init(&kq); 1377 kq.kq_refcnt = 1; 1378 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1379 kqueue_drain(&kq, td); 1380 kqueue_destroy(&kq); 1381 return (error); 1382 } 1383 1384 int 1385 kqueue_add_filteropts(int filt, struct filterops *filtops) 1386 { 1387 int error; 1388 1389 error = 0; 1390 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1391 printf( 1392 "trying to add a filterop that is out of range: %d is beyond %d\n", 1393 ~filt, EVFILT_SYSCOUNT); 1394 return EINVAL; 1395 } 1396 mtx_lock(&filterops_lock); 1397 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1398 sysfilt_ops[~filt].for_fop != NULL) 1399 error = EEXIST; 1400 else { 1401 sysfilt_ops[~filt].for_fop = filtops; 1402 sysfilt_ops[~filt].for_refcnt = 0; 1403 } 1404 mtx_unlock(&filterops_lock); 1405 1406 return (error); 1407 } 1408 1409 int 1410 kqueue_del_filteropts(int filt) 1411 { 1412 int error; 1413 1414 error = 0; 1415 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1416 return EINVAL; 1417 1418 mtx_lock(&filterops_lock); 1419 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1420 sysfilt_ops[~filt].for_fop == NULL) 1421 error = EINVAL; 1422 else if (sysfilt_ops[~filt].for_refcnt != 0) 1423 error = EBUSY; 1424 else { 1425 sysfilt_ops[~filt].for_fop = &null_filtops; 1426 sysfilt_ops[~filt].for_refcnt = 0; 1427 } 1428 mtx_unlock(&filterops_lock); 1429 1430 return error; 1431 } 1432 1433 static struct filterops * 1434 kqueue_fo_find(int filt) 1435 { 1436 1437 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1438 return NULL; 1439 1440 if (sysfilt_ops[~filt].for_nolock) 1441 return sysfilt_ops[~filt].for_fop; 1442 1443 mtx_lock(&filterops_lock); 1444 sysfilt_ops[~filt].for_refcnt++; 1445 if (sysfilt_ops[~filt].for_fop == NULL) 1446 sysfilt_ops[~filt].for_fop = &null_filtops; 1447 mtx_unlock(&filterops_lock); 1448 1449 return sysfilt_ops[~filt].for_fop; 1450 } 1451 1452 static void 1453 kqueue_fo_release(int filt) 1454 { 1455 1456 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1457 return; 1458 1459 if (sysfilt_ops[~filt].for_nolock) 1460 return; 1461 1462 mtx_lock(&filterops_lock); 1463 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1464 ("filter object refcount not valid on release")); 1465 sysfilt_ops[~filt].for_refcnt--; 1466 mtx_unlock(&filterops_lock); 1467 } 1468 1469 /* 1470 * A ref to kq (obtained via kqueue_acquire) must be held. 1471 */ 1472 static int 1473 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, 1474 int mflag) 1475 { 1476 struct filterops *fops; 1477 struct file *fp; 1478 struct knote *kn, *tkn; 1479 struct knlist *knl; 1480 int error, filt, event; 1481 int haskqglobal, filedesc_unlock; 1482 1483 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1484 return (EINVAL); 1485 1486 fp = NULL; 1487 kn = NULL; 1488 knl = NULL; 1489 error = 0; 1490 haskqglobal = 0; 1491 filedesc_unlock = 0; 1492 1493 filt = kev->filter; 1494 fops = kqueue_fo_find(filt); 1495 if (fops == NULL) 1496 return EINVAL; 1497 1498 if (kev->flags & EV_ADD) { 1499 /* 1500 * Prevent waiting with locks. Non-sleepable 1501 * allocation failures are handled in the loop, only 1502 * if the spare knote appears to be actually required. 1503 */ 1504 tkn = knote_alloc(mflag); 1505 } else { 1506 tkn = NULL; 1507 } 1508 1509 findkn: 1510 if (fops->f_isfd) { 1511 KASSERT(td != NULL, ("td is NULL")); 1512 if (kev->ident > INT_MAX) 1513 error = EBADF; 1514 else 1515 error = fget(td, kev->ident, &cap_event_rights, &fp); 1516 if (error) 1517 goto done; 1518 1519 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1520 kev->ident, M_NOWAIT) != 0) { 1521 /* try again */ 1522 fdrop(fp, td); 1523 fp = NULL; 1524 error = kqueue_expand(kq, fops, kev->ident, mflag); 1525 if (error) 1526 goto done; 1527 goto findkn; 1528 } 1529 1530 if (fp->f_type == DTYPE_KQUEUE) { 1531 /* 1532 * If we add some intelligence about what we are doing, 1533 * we should be able to support events on ourselves. 1534 * We need to know when we are doing this to prevent 1535 * getting both the knlist lock and the kq lock since 1536 * they are the same thing. 1537 */ 1538 if (fp->f_data == kq) { 1539 error = EINVAL; 1540 goto done; 1541 } 1542 1543 /* 1544 * Pre-lock the filedesc before the global 1545 * lock mutex, see the comment in 1546 * kqueue_close(). 1547 */ 1548 FILEDESC_XLOCK(td->td_proc->p_fd); 1549 filedesc_unlock = 1; 1550 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1551 } 1552 1553 KQ_LOCK(kq); 1554 if (kev->ident < kq->kq_knlistsize) { 1555 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1556 if (kev->filter == kn->kn_filter) 1557 break; 1558 } 1559 } else { 1560 if ((kev->flags & EV_ADD) == EV_ADD) { 1561 error = kqueue_expand(kq, fops, kev->ident, mflag); 1562 if (error != 0) 1563 goto done; 1564 } 1565 1566 KQ_LOCK(kq); 1567 1568 /* 1569 * If possible, find an existing knote to use for this kevent. 1570 */ 1571 if (kev->filter == EVFILT_PROC && 1572 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1573 /* This is an internal creation of a process tracking 1574 * note. Don't attempt to coalesce this with an 1575 * existing note. 1576 */ 1577 ; 1578 } else if (kq->kq_knhashmask != 0) { 1579 struct klist *list; 1580 1581 list = &kq->kq_knhash[ 1582 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1583 SLIST_FOREACH(kn, list, kn_link) 1584 if (kev->ident == kn->kn_id && 1585 kev->filter == kn->kn_filter) 1586 break; 1587 } 1588 } 1589 1590 /* knote is in the process of changing, wait for it to stabilize. */ 1591 if (kn != NULL && kn_in_flux(kn)) { 1592 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1593 if (filedesc_unlock) { 1594 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1595 filedesc_unlock = 0; 1596 } 1597 kq->kq_state |= KQ_FLUXWAIT; 1598 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1599 if (fp != NULL) { 1600 fdrop(fp, td); 1601 fp = NULL; 1602 } 1603 goto findkn; 1604 } 1605 1606 /* 1607 * kn now contains the matching knote, or NULL if no match 1608 */ 1609 if (kn == NULL) { 1610 if (kev->flags & EV_ADD) { 1611 kn = tkn; 1612 tkn = NULL; 1613 if (kn == NULL) { 1614 KQ_UNLOCK(kq); 1615 error = ENOMEM; 1616 goto done; 1617 } 1618 kn->kn_fp = fp; 1619 kn->kn_kq = kq; 1620 kn->kn_fop = fops; 1621 /* 1622 * apply reference counts to knote structure, and 1623 * do not release it at the end of this routine. 1624 */ 1625 fops = NULL; 1626 fp = NULL; 1627 1628 kn->kn_sfflags = kev->fflags; 1629 kn->kn_sdata = kev->data; 1630 kev->fflags = 0; 1631 kev->data = 0; 1632 kn->kn_kevent = *kev; 1633 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1634 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1635 kn->kn_status = KN_DETACHED; 1636 if ((kev->flags & EV_DISABLE) != 0) 1637 kn->kn_status |= KN_DISABLED; 1638 kn_enter_flux(kn); 1639 1640 error = knote_attach(kn, kq); 1641 KQ_UNLOCK(kq); 1642 if (error != 0) { 1643 tkn = kn; 1644 goto done; 1645 } 1646 1647 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1648 knote_drop_detached(kn, td); 1649 goto done; 1650 } 1651 knl = kn_list_lock(kn); 1652 goto done_ev_add; 1653 } else { 1654 /* No matching knote and the EV_ADD flag is not set. */ 1655 KQ_UNLOCK(kq); 1656 error = ENOENT; 1657 goto done; 1658 } 1659 } 1660 1661 if (kev->flags & EV_DELETE) { 1662 kn_enter_flux(kn); 1663 KQ_UNLOCK(kq); 1664 knote_drop(kn, td); 1665 goto done; 1666 } 1667 1668 if (kev->flags & EV_FORCEONESHOT) { 1669 kn->kn_flags |= EV_ONESHOT; 1670 KNOTE_ACTIVATE(kn, 1); 1671 } 1672 1673 if ((kev->flags & EV_ENABLE) != 0) 1674 kn->kn_status &= ~KN_DISABLED; 1675 else if ((kev->flags & EV_DISABLE) != 0) 1676 kn->kn_status |= KN_DISABLED; 1677 1678 /* 1679 * The user may change some filter values after the initial EV_ADD, 1680 * but doing so will not reset any filter which has already been 1681 * triggered. 1682 */ 1683 kn->kn_status |= KN_SCAN; 1684 kn_enter_flux(kn); 1685 KQ_UNLOCK(kq); 1686 knl = kn_list_lock(kn); 1687 kn->kn_kevent.udata = kev->udata; 1688 if (!fops->f_isfd && fops->f_touch != NULL) { 1689 fops->f_touch(kn, kev, EVENT_REGISTER); 1690 } else { 1691 kn->kn_sfflags = kev->fflags; 1692 kn->kn_sdata = kev->data; 1693 } 1694 1695 done_ev_add: 1696 /* 1697 * We can get here with kn->kn_knlist == NULL. This can happen when 1698 * the initial attach event decides that the event is "completed" 1699 * already, e.g., filt_procattach() is called on a zombie process. It 1700 * will call filt_proc() which will remove it from the list, and NULL 1701 * kn_knlist. 1702 * 1703 * KN_DISABLED will be stable while the knote is in flux, so the 1704 * unlocked read will not race with an update. 1705 */ 1706 if ((kn->kn_status & KN_DISABLED) == 0) 1707 event = kn->kn_fop->f_event(kn, 0); 1708 else 1709 event = 0; 1710 1711 KQ_LOCK(kq); 1712 if (event) 1713 kn->kn_status |= KN_ACTIVE; 1714 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1715 KN_ACTIVE) 1716 knote_enqueue(kn); 1717 kn->kn_status &= ~KN_SCAN; 1718 kn_leave_flux(kn); 1719 kn_list_unlock(knl); 1720 KQ_UNLOCK_FLUX(kq); 1721 1722 done: 1723 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1724 if (filedesc_unlock) 1725 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1726 if (fp != NULL) 1727 fdrop(fp, td); 1728 knote_free(tkn); 1729 if (fops != NULL) 1730 kqueue_fo_release(filt); 1731 return (error); 1732 } 1733 1734 static int 1735 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1736 { 1737 int error; 1738 struct kqueue *kq; 1739 1740 error = 0; 1741 1742 kq = fp->f_data; 1743 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1744 return (EBADF); 1745 *kqp = kq; 1746 KQ_LOCK(kq); 1747 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1748 KQ_UNLOCK(kq); 1749 return (EBADF); 1750 } 1751 kq->kq_refcnt++; 1752 KQ_UNLOCK(kq); 1753 1754 return error; 1755 } 1756 1757 static void 1758 kqueue_release(struct kqueue *kq, int locked) 1759 { 1760 if (locked) 1761 KQ_OWNED(kq); 1762 else 1763 KQ_LOCK(kq); 1764 kq->kq_refcnt--; 1765 if (kq->kq_refcnt == 1) 1766 wakeup(&kq->kq_refcnt); 1767 if (!locked) 1768 KQ_UNLOCK(kq); 1769 } 1770 1771 static void 1772 kqueue_schedtask(struct kqueue *kq) 1773 { 1774 1775 KQ_OWNED(kq); 1776 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1777 ("scheduling kqueue task while draining")); 1778 1779 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1780 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1781 kq->kq_state |= KQ_TASKSCHED; 1782 } 1783 } 1784 1785 /* 1786 * Expand the kq to make sure we have storage for fops/ident pair. 1787 * 1788 * Return 0 on success (or no work necessary), return errno on failure. 1789 */ 1790 static int 1791 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1792 int mflag) 1793 { 1794 struct klist *list, *tmp_knhash, *to_free; 1795 u_long tmp_knhashmask; 1796 int error, fd, size; 1797 1798 KQ_NOTOWNED(kq); 1799 1800 error = 0; 1801 to_free = NULL; 1802 if (fops->f_isfd) { 1803 fd = ident; 1804 if (kq->kq_knlistsize <= fd) { 1805 size = kq->kq_knlistsize; 1806 while (size <= fd) 1807 size += KQEXTENT; 1808 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1809 if (list == NULL) 1810 return ENOMEM; 1811 KQ_LOCK(kq); 1812 if ((kq->kq_state & KQ_CLOSING) != 0) { 1813 to_free = list; 1814 error = EBADF; 1815 } else if (kq->kq_knlistsize > fd) { 1816 to_free = list; 1817 } else { 1818 if (kq->kq_knlist != NULL) { 1819 bcopy(kq->kq_knlist, list, 1820 kq->kq_knlistsize * sizeof(*list)); 1821 to_free = kq->kq_knlist; 1822 kq->kq_knlist = NULL; 1823 } 1824 bzero((caddr_t)list + 1825 kq->kq_knlistsize * sizeof(*list), 1826 (size - kq->kq_knlistsize) * sizeof(*list)); 1827 kq->kq_knlistsize = size; 1828 kq->kq_knlist = list; 1829 } 1830 KQ_UNLOCK(kq); 1831 } 1832 } else { 1833 if (kq->kq_knhashmask == 0) { 1834 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE, 1835 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ? 1836 HASH_WAITOK : HASH_NOWAIT); 1837 if (tmp_knhash == NULL) 1838 return (ENOMEM); 1839 KQ_LOCK(kq); 1840 if ((kq->kq_state & KQ_CLOSING) != 0) { 1841 to_free = tmp_knhash; 1842 error = EBADF; 1843 } else if (kq->kq_knhashmask == 0) { 1844 kq->kq_knhash = tmp_knhash; 1845 kq->kq_knhashmask = tmp_knhashmask; 1846 } else { 1847 to_free = tmp_knhash; 1848 } 1849 KQ_UNLOCK(kq); 1850 } 1851 } 1852 free(to_free, M_KQUEUE); 1853 1854 KQ_NOTOWNED(kq); 1855 return (error); 1856 } 1857 1858 static void 1859 kqueue_task(void *arg, int pending) 1860 { 1861 struct kqueue *kq; 1862 int haskqglobal; 1863 1864 haskqglobal = 0; 1865 kq = arg; 1866 1867 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1868 KQ_LOCK(kq); 1869 1870 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1871 1872 kq->kq_state &= ~KQ_TASKSCHED; 1873 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1874 wakeup(&kq->kq_state); 1875 } 1876 KQ_UNLOCK(kq); 1877 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1878 } 1879 1880 /* 1881 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1882 * We treat KN_MARKER knotes as if they are in flux. 1883 */ 1884 static int 1885 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1886 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1887 { 1888 struct kevent *kevp; 1889 struct knote *kn, *marker; 1890 struct knlist *knl; 1891 sbintime_t asbt, rsbt; 1892 int count, error, haskqglobal, influx, nkev, touch; 1893 1894 count = maxevents; 1895 nkev = 0; 1896 error = 0; 1897 haskqglobal = 0; 1898 1899 if (maxevents == 0) 1900 goto done_nl; 1901 if (maxevents < 0) { 1902 error = EINVAL; 1903 goto done_nl; 1904 } 1905 1906 rsbt = 0; 1907 if (tsp != NULL) { 1908 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1909 tsp->tv_nsec >= 1000000000) { 1910 error = EINVAL; 1911 goto done_nl; 1912 } 1913 if (timespecisset(tsp)) { 1914 if (tsp->tv_sec <= INT32_MAX) { 1915 rsbt = tstosbt(*tsp); 1916 if (TIMESEL(&asbt, rsbt)) 1917 asbt += tc_tick_sbt; 1918 if (asbt <= SBT_MAX - rsbt) 1919 asbt += rsbt; 1920 else 1921 asbt = 0; 1922 rsbt >>= tc_precexp; 1923 } else 1924 asbt = 0; 1925 } else 1926 asbt = -1; 1927 } else 1928 asbt = 0; 1929 marker = knote_alloc(M_WAITOK); 1930 marker->kn_status = KN_MARKER; 1931 KQ_LOCK(kq); 1932 1933 retry: 1934 kevp = keva; 1935 if (kq->kq_count == 0) { 1936 if (asbt == -1) { 1937 error = EWOULDBLOCK; 1938 } else { 1939 kq->kq_state |= KQ_SLEEP; 1940 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1941 "kqread", asbt, rsbt, C_ABSOLUTE); 1942 } 1943 if (error == 0) 1944 goto retry; 1945 /* don't restart after signals... */ 1946 if (error == ERESTART) 1947 error = EINTR; 1948 else if (error == EWOULDBLOCK) 1949 error = 0; 1950 goto done; 1951 } 1952 1953 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1954 influx = 0; 1955 while (count) { 1956 KQ_OWNED(kq); 1957 kn = TAILQ_FIRST(&kq->kq_head); 1958 1959 if ((kn->kn_status == KN_MARKER && kn != marker) || 1960 kn_in_flux(kn)) { 1961 if (influx) { 1962 influx = 0; 1963 KQ_FLUX_WAKEUP(kq); 1964 } 1965 kq->kq_state |= KQ_FLUXWAIT; 1966 error = msleep(kq, &kq->kq_lock, PSOCK, 1967 "kqflxwt", 0); 1968 continue; 1969 } 1970 1971 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1972 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1973 kn->kn_status &= ~KN_QUEUED; 1974 kq->kq_count--; 1975 continue; 1976 } 1977 if (kn == marker) { 1978 KQ_FLUX_WAKEUP(kq); 1979 if (count == maxevents) 1980 goto retry; 1981 goto done; 1982 } 1983 KASSERT(!kn_in_flux(kn), 1984 ("knote %p is unexpectedly in flux", kn)); 1985 1986 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1987 kn->kn_status &= ~KN_QUEUED; 1988 kn_enter_flux(kn); 1989 kq->kq_count--; 1990 KQ_UNLOCK(kq); 1991 /* 1992 * We don't need to lock the list since we've 1993 * marked it as in flux. 1994 */ 1995 knote_drop(kn, td); 1996 KQ_LOCK(kq); 1997 continue; 1998 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1999 kn->kn_status &= ~KN_QUEUED; 2000 kn_enter_flux(kn); 2001 kq->kq_count--; 2002 KQ_UNLOCK(kq); 2003 /* 2004 * We don't need to lock the list since we've 2005 * marked the knote as being in flux. 2006 */ 2007 *kevp = kn->kn_kevent; 2008 knote_drop(kn, td); 2009 KQ_LOCK(kq); 2010 kn = NULL; 2011 } else { 2012 kn->kn_status |= KN_SCAN; 2013 kn_enter_flux(kn); 2014 KQ_UNLOCK(kq); 2015 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 2016 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 2017 knl = kn_list_lock(kn); 2018 if (kn->kn_fop->f_event(kn, 0) == 0) { 2019 KQ_LOCK(kq); 2020 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 2021 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 2022 KN_SCAN); 2023 kn_leave_flux(kn); 2024 kq->kq_count--; 2025 kn_list_unlock(knl); 2026 influx = 1; 2027 continue; 2028 } 2029 touch = (!kn->kn_fop->f_isfd && 2030 kn->kn_fop->f_touch != NULL); 2031 if (touch) 2032 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 2033 else 2034 *kevp = kn->kn_kevent; 2035 KQ_LOCK(kq); 2036 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 2037 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 2038 /* 2039 * Manually clear knotes who weren't 2040 * 'touch'ed. 2041 */ 2042 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 2043 kn->kn_data = 0; 2044 kn->kn_fflags = 0; 2045 } 2046 if (kn->kn_flags & EV_DISPATCH) 2047 kn->kn_status |= KN_DISABLED; 2048 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 2049 kq->kq_count--; 2050 } else 2051 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2052 2053 kn->kn_status &= ~KN_SCAN; 2054 kn_leave_flux(kn); 2055 kn_list_unlock(knl); 2056 influx = 1; 2057 } 2058 2059 /* we are returning a copy to the user */ 2060 kevp++; 2061 nkev++; 2062 count--; 2063 2064 if (nkev == KQ_NEVENTS) { 2065 influx = 0; 2066 KQ_UNLOCK_FLUX(kq); 2067 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 2068 nkev = 0; 2069 kevp = keva; 2070 KQ_LOCK(kq); 2071 if (error) 2072 break; 2073 } 2074 } 2075 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 2076 done: 2077 KQ_OWNED(kq); 2078 KQ_UNLOCK_FLUX(kq); 2079 knote_free(marker); 2080 done_nl: 2081 KQ_NOTOWNED(kq); 2082 if (nkev != 0) 2083 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 2084 td->td_retval[0] = maxevents - count; 2085 return (error); 2086 } 2087 2088 /*ARGSUSED*/ 2089 static int 2090 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 2091 struct ucred *active_cred, struct thread *td) 2092 { 2093 /* 2094 * Enabling sigio causes two major problems: 2095 * 1) infinite recursion: 2096 * Synopsys: kevent is being used to track signals and have FIOASYNC 2097 * set. On receipt of a signal this will cause a kqueue to recurse 2098 * into itself over and over. Sending the sigio causes the kqueue 2099 * to become ready, which in turn posts sigio again, forever. 2100 * Solution: this can be solved by setting a flag in the kqueue that 2101 * we have a SIGIO in progress. 2102 * 2) locking problems: 2103 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 2104 * us above the proc and pgrp locks. 2105 * Solution: Post a signal using an async mechanism, being sure to 2106 * record a generation count in the delivery so that we do not deliver 2107 * a signal to the wrong process. 2108 * 2109 * Note, these two mechanisms are somewhat mutually exclusive! 2110 */ 2111 #if 0 2112 struct kqueue *kq; 2113 2114 kq = fp->f_data; 2115 switch (cmd) { 2116 case FIOASYNC: 2117 if (*(int *)data) { 2118 kq->kq_state |= KQ_ASYNC; 2119 } else { 2120 kq->kq_state &= ~KQ_ASYNC; 2121 } 2122 return (0); 2123 2124 case FIOSETOWN: 2125 return (fsetown(*(int *)data, &kq->kq_sigio)); 2126 2127 case FIOGETOWN: 2128 *(int *)data = fgetown(&kq->kq_sigio); 2129 return (0); 2130 } 2131 #endif 2132 2133 return (ENOTTY); 2134 } 2135 2136 /*ARGSUSED*/ 2137 static int 2138 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 2139 struct thread *td) 2140 { 2141 struct kqueue *kq; 2142 int revents = 0; 2143 int error; 2144 2145 if ((error = kqueue_acquire(fp, &kq))) 2146 return POLLERR; 2147 2148 KQ_LOCK(kq); 2149 if (events & (POLLIN | POLLRDNORM)) { 2150 if (kq->kq_count) { 2151 revents |= events & (POLLIN | POLLRDNORM); 2152 } else { 2153 selrecord(td, &kq->kq_sel); 2154 if (SEL_WAITING(&kq->kq_sel)) 2155 kq->kq_state |= KQ_SEL; 2156 } 2157 } 2158 kqueue_release(kq, 1); 2159 KQ_UNLOCK(kq); 2160 return (revents); 2161 } 2162 2163 /*ARGSUSED*/ 2164 static int 2165 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 2166 struct thread *td) 2167 { 2168 2169 bzero((void *)st, sizeof *st); 2170 /* 2171 * We no longer return kq_count because the unlocked value is useless. 2172 * If you spent all this time getting the count, why not spend your 2173 * syscall better by calling kevent? 2174 * 2175 * XXX - This is needed for libc_r. 2176 */ 2177 st->st_mode = S_IFIFO; 2178 return (0); 2179 } 2180 2181 static void 2182 kqueue_drain(struct kqueue *kq, struct thread *td) 2183 { 2184 struct knote *kn; 2185 int i; 2186 2187 KQ_LOCK(kq); 2188 2189 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 2190 ("kqueue already closing")); 2191 kq->kq_state |= KQ_CLOSING; 2192 if (kq->kq_refcnt > 1) 2193 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 2194 2195 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 2196 2197 KASSERT(knlist_empty(&kq->kq_sel.si_note), 2198 ("kqueue's knlist not empty")); 2199 2200 for (i = 0; i < kq->kq_knlistsize; i++) { 2201 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 2202 if (kn_in_flux(kn)) { 2203 kq->kq_state |= KQ_FLUXWAIT; 2204 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 2205 continue; 2206 } 2207 kn_enter_flux(kn); 2208 KQ_UNLOCK(kq); 2209 knote_drop(kn, td); 2210 KQ_LOCK(kq); 2211 } 2212 } 2213 if (kq->kq_knhashmask != 0) { 2214 for (i = 0; i <= kq->kq_knhashmask; i++) { 2215 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 2216 if (kn_in_flux(kn)) { 2217 kq->kq_state |= KQ_FLUXWAIT; 2218 msleep(kq, &kq->kq_lock, PSOCK, 2219 "kqclo2", 0); 2220 continue; 2221 } 2222 kn_enter_flux(kn); 2223 KQ_UNLOCK(kq); 2224 knote_drop(kn, td); 2225 KQ_LOCK(kq); 2226 } 2227 } 2228 } 2229 2230 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 2231 kq->kq_state |= KQ_TASKDRAIN; 2232 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 2233 } 2234 2235 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2236 selwakeuppri(&kq->kq_sel, PSOCK); 2237 if (!SEL_WAITING(&kq->kq_sel)) 2238 kq->kq_state &= ~KQ_SEL; 2239 } 2240 2241 KQ_UNLOCK(kq); 2242 } 2243 2244 static void 2245 kqueue_destroy(struct kqueue *kq) 2246 { 2247 2248 KASSERT(kq->kq_fdp == NULL, 2249 ("kqueue still attached to a file descriptor")); 2250 seldrain(&kq->kq_sel); 2251 knlist_destroy(&kq->kq_sel.si_note); 2252 mtx_destroy(&kq->kq_lock); 2253 2254 if (kq->kq_knhash != NULL) 2255 free(kq->kq_knhash, M_KQUEUE); 2256 if (kq->kq_knlist != NULL) 2257 free(kq->kq_knlist, M_KQUEUE); 2258 2259 funsetown(&kq->kq_sigio); 2260 } 2261 2262 /*ARGSUSED*/ 2263 static int 2264 kqueue_close(struct file *fp, struct thread *td) 2265 { 2266 struct kqueue *kq = fp->f_data; 2267 struct filedesc *fdp; 2268 int error; 2269 int filedesc_unlock; 2270 2271 if ((error = kqueue_acquire(fp, &kq))) 2272 return error; 2273 kqueue_drain(kq, td); 2274 2275 /* 2276 * We could be called due to the knote_drop() doing fdrop(), 2277 * called from kqueue_register(). In this case the global 2278 * lock is owned, and filedesc sx is locked before, to not 2279 * take the sleepable lock after non-sleepable. 2280 */ 2281 fdp = kq->kq_fdp; 2282 kq->kq_fdp = NULL; 2283 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 2284 FILEDESC_XLOCK(fdp); 2285 filedesc_unlock = 1; 2286 } else 2287 filedesc_unlock = 0; 2288 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 2289 if (filedesc_unlock) 2290 FILEDESC_XUNLOCK(fdp); 2291 2292 kqueue_destroy(kq); 2293 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 2294 crfree(kq->kq_cred); 2295 free(kq, M_KQUEUE); 2296 fp->f_data = NULL; 2297 2298 return (0); 2299 } 2300 2301 static int 2302 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2303 { 2304 2305 kif->kf_type = KF_TYPE_KQUEUE; 2306 return (0); 2307 } 2308 2309 static void 2310 kqueue_wakeup(struct kqueue *kq) 2311 { 2312 KQ_OWNED(kq); 2313 2314 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2315 kq->kq_state &= ~KQ_SLEEP; 2316 wakeup(kq); 2317 } 2318 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2319 selwakeuppri(&kq->kq_sel, PSOCK); 2320 if (!SEL_WAITING(&kq->kq_sel)) 2321 kq->kq_state &= ~KQ_SEL; 2322 } 2323 if (!knlist_empty(&kq->kq_sel.si_note)) 2324 kqueue_schedtask(kq); 2325 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2326 pgsigio(&kq->kq_sigio, SIGIO, 0); 2327 } 2328 } 2329 2330 /* 2331 * Walk down a list of knotes, activating them if their event has triggered. 2332 * 2333 * There is a possibility to optimize in the case of one kq watching another. 2334 * Instead of scheduling a task to wake it up, you could pass enough state 2335 * down the chain to make up the parent kqueue. Make this code functional 2336 * first. 2337 */ 2338 void 2339 knote(struct knlist *list, long hint, int lockflags) 2340 { 2341 struct kqueue *kq; 2342 struct knote *kn, *tkn; 2343 int error; 2344 2345 if (list == NULL) 2346 return; 2347 2348 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2349 2350 if ((lockflags & KNF_LISTLOCKED) == 0) 2351 list->kl_lock(list->kl_lockarg); 2352 2353 /* 2354 * If we unlock the list lock (and enter influx), we can 2355 * eliminate the kqueue scheduling, but this will introduce 2356 * four lock/unlock's for each knote to test. Also, marker 2357 * would be needed to keep iteration position, since filters 2358 * or other threads could remove events. 2359 */ 2360 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2361 kq = kn->kn_kq; 2362 KQ_LOCK(kq); 2363 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2364 /* 2365 * Do not process the influx notes, except for 2366 * the influx coming from the kq unlock in the 2367 * kqueue_scan(). In the later case, we do 2368 * not interfere with the scan, since the code 2369 * fragment in kqueue_scan() locks the knlist, 2370 * and cannot proceed until we finished. 2371 */ 2372 KQ_UNLOCK(kq); 2373 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2374 kn_enter_flux(kn); 2375 KQ_UNLOCK(kq); 2376 error = kn->kn_fop->f_event(kn, hint); 2377 KQ_LOCK(kq); 2378 kn_leave_flux(kn); 2379 if (error) 2380 KNOTE_ACTIVATE(kn, 1); 2381 KQ_UNLOCK_FLUX(kq); 2382 } else { 2383 if (kn->kn_fop->f_event(kn, hint)) 2384 KNOTE_ACTIVATE(kn, 1); 2385 KQ_UNLOCK(kq); 2386 } 2387 } 2388 if ((lockflags & KNF_LISTLOCKED) == 0) 2389 list->kl_unlock(list->kl_lockarg); 2390 } 2391 2392 /* 2393 * add a knote to a knlist 2394 */ 2395 void 2396 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2397 { 2398 2399 KNL_ASSERT_LOCK(knl, islocked); 2400 KQ_NOTOWNED(kn->kn_kq); 2401 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2402 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2403 ("knote %p was not detached", kn)); 2404 if (!islocked) 2405 knl->kl_lock(knl->kl_lockarg); 2406 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2407 if (!islocked) 2408 knl->kl_unlock(knl->kl_lockarg); 2409 KQ_LOCK(kn->kn_kq); 2410 kn->kn_knlist = knl; 2411 kn->kn_status &= ~KN_DETACHED; 2412 KQ_UNLOCK(kn->kn_kq); 2413 } 2414 2415 static void 2416 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2417 int kqislocked) 2418 { 2419 2420 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2421 KNL_ASSERT_LOCK(knl, knlislocked); 2422 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2423 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2424 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2425 ("knote %p was already detached", kn)); 2426 if (!knlislocked) 2427 knl->kl_lock(knl->kl_lockarg); 2428 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2429 kn->kn_knlist = NULL; 2430 if (!knlislocked) 2431 kn_list_unlock(knl); 2432 if (!kqislocked) 2433 KQ_LOCK(kn->kn_kq); 2434 kn->kn_status |= KN_DETACHED; 2435 if (!kqislocked) 2436 KQ_UNLOCK(kn->kn_kq); 2437 } 2438 2439 /* 2440 * remove knote from the specified knlist 2441 */ 2442 void 2443 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2444 { 2445 2446 knlist_remove_kq(knl, kn, islocked, 0); 2447 } 2448 2449 int 2450 knlist_empty(struct knlist *knl) 2451 { 2452 2453 KNL_ASSERT_LOCKED(knl); 2454 return (SLIST_EMPTY(&knl->kl_list)); 2455 } 2456 2457 static struct mtx knlist_lock; 2458 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2459 MTX_DEF); 2460 static void knlist_mtx_lock(void *arg); 2461 static void knlist_mtx_unlock(void *arg); 2462 2463 static void 2464 knlist_mtx_lock(void *arg) 2465 { 2466 2467 mtx_lock((struct mtx *)arg); 2468 } 2469 2470 static void 2471 knlist_mtx_unlock(void *arg) 2472 { 2473 2474 mtx_unlock((struct mtx *)arg); 2475 } 2476 2477 static void 2478 knlist_mtx_assert_lock(void *arg, int what) 2479 { 2480 2481 if (what == LA_LOCKED) 2482 mtx_assert((struct mtx *)arg, MA_OWNED); 2483 else 2484 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2485 } 2486 2487 static void 2488 knlist_rw_rlock(void *arg) 2489 { 2490 2491 rw_rlock((struct rwlock *)arg); 2492 } 2493 2494 static void 2495 knlist_rw_runlock(void *arg) 2496 { 2497 2498 rw_runlock((struct rwlock *)arg); 2499 } 2500 2501 static void 2502 knlist_rw_assert_lock(void *arg, int what) 2503 { 2504 2505 if (what == LA_LOCKED) 2506 rw_assert((struct rwlock *)arg, RA_LOCKED); 2507 else 2508 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2509 } 2510 2511 void 2512 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2513 void (*kl_unlock)(void *), 2514 void (*kl_assert_lock)(void *, int)) 2515 { 2516 2517 if (lock == NULL) 2518 knl->kl_lockarg = &knlist_lock; 2519 else 2520 knl->kl_lockarg = lock; 2521 2522 if (kl_lock == NULL) 2523 knl->kl_lock = knlist_mtx_lock; 2524 else 2525 knl->kl_lock = kl_lock; 2526 if (kl_unlock == NULL) 2527 knl->kl_unlock = knlist_mtx_unlock; 2528 else 2529 knl->kl_unlock = kl_unlock; 2530 if (kl_assert_lock == NULL) 2531 knl->kl_assert_lock = knlist_mtx_assert_lock; 2532 else 2533 knl->kl_assert_lock = kl_assert_lock; 2534 2535 knl->kl_autodestroy = 0; 2536 SLIST_INIT(&knl->kl_list); 2537 } 2538 2539 void 2540 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2541 { 2542 2543 knlist_init(knl, lock, NULL, NULL, NULL); 2544 } 2545 2546 struct knlist * 2547 knlist_alloc(struct mtx *lock) 2548 { 2549 struct knlist *knl; 2550 2551 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2552 knlist_init_mtx(knl, lock); 2553 return (knl); 2554 } 2555 2556 void 2557 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2558 { 2559 2560 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2561 knlist_rw_assert_lock); 2562 } 2563 2564 void 2565 knlist_destroy(struct knlist *knl) 2566 { 2567 2568 KASSERT(KNLIST_EMPTY(knl), 2569 ("destroying knlist %p with knotes on it", knl)); 2570 } 2571 2572 void 2573 knlist_detach(struct knlist *knl) 2574 { 2575 2576 KNL_ASSERT_LOCKED(knl); 2577 knl->kl_autodestroy = 1; 2578 if (knlist_empty(knl)) { 2579 knlist_destroy(knl); 2580 free(knl, M_KQUEUE); 2581 } 2582 } 2583 2584 /* 2585 * Even if we are locked, we may need to drop the lock to allow any influx 2586 * knotes time to "settle". 2587 */ 2588 void 2589 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2590 { 2591 struct knote *kn, *kn2; 2592 struct kqueue *kq; 2593 2594 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2595 if (islocked) 2596 KNL_ASSERT_LOCKED(knl); 2597 else { 2598 KNL_ASSERT_UNLOCKED(knl); 2599 again: /* need to reacquire lock since we have dropped it */ 2600 knl->kl_lock(knl->kl_lockarg); 2601 } 2602 2603 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2604 kq = kn->kn_kq; 2605 KQ_LOCK(kq); 2606 if (kn_in_flux(kn)) { 2607 KQ_UNLOCK(kq); 2608 continue; 2609 } 2610 knlist_remove_kq(knl, kn, 1, 1); 2611 if (killkn) { 2612 kn_enter_flux(kn); 2613 KQ_UNLOCK(kq); 2614 knote_drop_detached(kn, td); 2615 } else { 2616 /* Make sure cleared knotes disappear soon */ 2617 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2618 KQ_UNLOCK(kq); 2619 } 2620 kq = NULL; 2621 } 2622 2623 if (!SLIST_EMPTY(&knl->kl_list)) { 2624 /* there are still in flux knotes remaining */ 2625 kn = SLIST_FIRST(&knl->kl_list); 2626 kq = kn->kn_kq; 2627 KQ_LOCK(kq); 2628 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2629 knl->kl_unlock(knl->kl_lockarg); 2630 kq->kq_state |= KQ_FLUXWAIT; 2631 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2632 kq = NULL; 2633 goto again; 2634 } 2635 2636 if (islocked) 2637 KNL_ASSERT_LOCKED(knl); 2638 else { 2639 knl->kl_unlock(knl->kl_lockarg); 2640 KNL_ASSERT_UNLOCKED(knl); 2641 } 2642 } 2643 2644 /* 2645 * Remove all knotes referencing a specified fd must be called with FILEDESC 2646 * lock. This prevents a race where a new fd comes along and occupies the 2647 * entry and we attach a knote to the fd. 2648 */ 2649 void 2650 knote_fdclose(struct thread *td, int fd) 2651 { 2652 struct filedesc *fdp = td->td_proc->p_fd; 2653 struct kqueue *kq; 2654 struct knote *kn; 2655 int influx; 2656 2657 FILEDESC_XLOCK_ASSERT(fdp); 2658 2659 /* 2660 * We shouldn't have to worry about new kevents appearing on fd 2661 * since filedesc is locked. 2662 */ 2663 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2664 KQ_LOCK(kq); 2665 2666 again: 2667 influx = 0; 2668 while (kq->kq_knlistsize > fd && 2669 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2670 if (kn_in_flux(kn)) { 2671 /* someone else might be waiting on our knote */ 2672 if (influx) 2673 wakeup(kq); 2674 kq->kq_state |= KQ_FLUXWAIT; 2675 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2676 goto again; 2677 } 2678 kn_enter_flux(kn); 2679 KQ_UNLOCK(kq); 2680 influx = 1; 2681 knote_drop(kn, td); 2682 KQ_LOCK(kq); 2683 } 2684 KQ_UNLOCK_FLUX(kq); 2685 } 2686 } 2687 2688 static int 2689 knote_attach(struct knote *kn, struct kqueue *kq) 2690 { 2691 struct klist *list; 2692 2693 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2694 KQ_OWNED(kq); 2695 2696 if ((kq->kq_state & KQ_CLOSING) != 0) 2697 return (EBADF); 2698 if (kn->kn_fop->f_isfd) { 2699 if (kn->kn_id >= kq->kq_knlistsize) 2700 return (ENOMEM); 2701 list = &kq->kq_knlist[kn->kn_id]; 2702 } else { 2703 if (kq->kq_knhash == NULL) 2704 return (ENOMEM); 2705 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2706 } 2707 SLIST_INSERT_HEAD(list, kn, kn_link); 2708 return (0); 2709 } 2710 2711 static void 2712 knote_drop(struct knote *kn, struct thread *td) 2713 { 2714 2715 if ((kn->kn_status & KN_DETACHED) == 0) 2716 kn->kn_fop->f_detach(kn); 2717 knote_drop_detached(kn, td); 2718 } 2719 2720 static void 2721 knote_drop_detached(struct knote *kn, struct thread *td) 2722 { 2723 struct kqueue *kq; 2724 struct klist *list; 2725 2726 kq = kn->kn_kq; 2727 2728 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2729 ("knote %p still attached", kn)); 2730 KQ_NOTOWNED(kq); 2731 2732 KQ_LOCK(kq); 2733 KASSERT(kn->kn_influx == 1, 2734 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2735 2736 if (kn->kn_fop->f_isfd) 2737 list = &kq->kq_knlist[kn->kn_id]; 2738 else 2739 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2740 2741 if (!SLIST_EMPTY(list)) 2742 SLIST_REMOVE(list, kn, knote, kn_link); 2743 if (kn->kn_status & KN_QUEUED) 2744 knote_dequeue(kn); 2745 KQ_UNLOCK_FLUX(kq); 2746 2747 if (kn->kn_fop->f_isfd) { 2748 fdrop(kn->kn_fp, td); 2749 kn->kn_fp = NULL; 2750 } 2751 kqueue_fo_release(kn->kn_kevent.filter); 2752 kn->kn_fop = NULL; 2753 knote_free(kn); 2754 } 2755 2756 static void 2757 knote_enqueue(struct knote *kn) 2758 { 2759 struct kqueue *kq = kn->kn_kq; 2760 2761 KQ_OWNED(kn->kn_kq); 2762 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2763 2764 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2765 kn->kn_status |= KN_QUEUED; 2766 kq->kq_count++; 2767 kqueue_wakeup(kq); 2768 } 2769 2770 static void 2771 knote_dequeue(struct knote *kn) 2772 { 2773 struct kqueue *kq = kn->kn_kq; 2774 2775 KQ_OWNED(kn->kn_kq); 2776 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2777 2778 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2779 kn->kn_status &= ~KN_QUEUED; 2780 kq->kq_count--; 2781 } 2782 2783 static void 2784 knote_init(void) 2785 { 2786 2787 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2788 NULL, NULL, UMA_ALIGN_PTR, 0); 2789 } 2790 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2791 2792 static struct knote * 2793 knote_alloc(int mflag) 2794 { 2795 2796 return (uma_zalloc(knote_zone, mflag | M_ZERO)); 2797 } 2798 2799 static void 2800 knote_free(struct knote *kn) 2801 { 2802 2803 uma_zfree(knote_zone, kn); 2804 } 2805 2806 /* 2807 * Register the kev w/ the kq specified by fd. 2808 */ 2809 int 2810 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag) 2811 { 2812 struct kqueue *kq; 2813 struct file *fp; 2814 cap_rights_t rights; 2815 int error; 2816 2817 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE), 2818 &fp); 2819 if (error != 0) 2820 return (error); 2821 if ((error = kqueue_acquire(fp, &kq)) != 0) 2822 goto noacquire; 2823 2824 error = kqueue_register(kq, kev, td, mflag); 2825 kqueue_release(kq, 0); 2826 2827 noacquire: 2828 fdrop(fp, td); 2829 return (error); 2830 } 2831