Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
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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 int filt_timerattach(struct knote *kn); 165 static void filt_timerdetach(struct knote *kn); 166 static void filt_timerstart(struct knote *kn, sbintime_t to); 167 static void filt_timertouch(struct knote *kn, struct kevent *kev, 168 u_long type); 169 static int filt_timervalidate(struct knote *kn, sbintime_t *to); 170 static int filt_timer(struct knote *kn, long hint); 171 static int filt_userattach(struct knote *kn); 172 static void filt_userdetach(struct knote *kn); 173 static int filt_user(struct knote *kn, long hint); 174 static void filt_usertouch(struct knote *kn, struct kevent *kev, 175 u_long type); 176 177 static struct filterops file_filtops = { 178 .f_isfd = 1, 179 .f_attach = filt_fileattach, 180 }; 181 static struct filterops kqread_filtops = { 182 .f_isfd = 1, 183 .f_detach = filt_kqdetach, 184 .f_event = filt_kqueue, 185 }; 186 /* XXX - move to kern_proc.c? */ 187 static struct filterops proc_filtops = { 188 .f_isfd = 0, 189 .f_attach = filt_procattach, 190 .f_detach = filt_procdetach, 191 .f_event = filt_proc, 192 }; 193 static struct filterops timer_filtops = { 194 .f_isfd = 0, 195 .f_attach = filt_timerattach, 196 .f_detach = filt_timerdetach, 197 .f_event = filt_timer, 198 .f_touch = filt_timertouch, 199 }; 200 static struct filterops user_filtops = { 201 .f_attach = filt_userattach, 202 .f_detach = filt_userdetach, 203 .f_event = filt_user, 204 .f_touch = filt_usertouch, 205 }; 206 207 static uma_zone_t knote_zone; 208 static unsigned int kq_ncallouts = 0; 209 static unsigned int kq_calloutmax = 4 * 1024; 210 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 211 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 212 213 /* XXX - ensure not influx ? */ 214 #define KNOTE_ACTIVATE(kn, islock) do { \ 215 if ((islock)) \ 216 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 217 else \ 218 KQ_LOCK((kn)->kn_kq); \ 219 (kn)->kn_status |= KN_ACTIVE; \ 220 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 221 knote_enqueue((kn)); \ 222 if (!(islock)) \ 223 KQ_UNLOCK((kn)->kn_kq); \ 224 } while(0) 225 #define KQ_LOCK(kq) do { \ 226 mtx_lock(&(kq)->kq_lock); \ 227 } while (0) 228 #define KQ_FLUX_WAKEUP(kq) do { \ 229 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 230 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 231 wakeup((kq)); \ 232 } \ 233 } while (0) 234 #define KQ_UNLOCK_FLUX(kq) do { \ 235 KQ_FLUX_WAKEUP(kq); \ 236 mtx_unlock(&(kq)->kq_lock); \ 237 } while (0) 238 #define KQ_UNLOCK(kq) do { \ 239 mtx_unlock(&(kq)->kq_lock); \ 240 } while (0) 241 #define KQ_OWNED(kq) do { \ 242 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 243 } while (0) 244 #define KQ_NOTOWNED(kq) do { \ 245 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 246 } while (0) 247 248 static struct knlist * 249 kn_list_lock(struct knote *kn) 250 { 251 struct knlist *knl; 252 253 knl = kn->kn_knlist; 254 if (knl != NULL) 255 knl->kl_lock(knl->kl_lockarg); 256 return (knl); 257 } 258 259 static void 260 kn_list_unlock(struct knlist *knl) 261 { 262 bool do_free; 263 264 if (knl == NULL) 265 return; 266 do_free = knl->kl_autodestroy && knlist_empty(knl); 267 knl->kl_unlock(knl->kl_lockarg); 268 if (do_free) { 269 knlist_destroy(knl); 270 free(knl, M_KQUEUE); 271 } 272 } 273 274 static bool 275 kn_in_flux(struct knote *kn) 276 { 277 278 return (kn->kn_influx > 0); 279 } 280 281 static void 282 kn_enter_flux(struct knote *kn) 283 { 284 285 KQ_OWNED(kn->kn_kq); 286 MPASS(kn->kn_influx < INT_MAX); 287 kn->kn_influx++; 288 } 289 290 static bool 291 kn_leave_flux(struct knote *kn) 292 { 293 294 KQ_OWNED(kn->kn_kq); 295 MPASS(kn->kn_influx > 0); 296 kn->kn_influx--; 297 return (kn->kn_influx == 0); 298 } 299 300 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 301 if (islocked) \ 302 KNL_ASSERT_LOCKED(knl); \ 303 else \ 304 KNL_ASSERT_UNLOCKED(knl); \ 305 } while (0) 306 #ifdef INVARIANTS 307 #define KNL_ASSERT_LOCKED(knl) do { \ 308 knl->kl_assert_lock((knl)->kl_lockarg, LA_LOCKED); \ 309 } while (0) 310 #define KNL_ASSERT_UNLOCKED(knl) do { \ 311 knl->kl_assert_lock((knl)->kl_lockarg, LA_UNLOCKED); \ 312 } while (0) 313 #else /* !INVARIANTS */ 314 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 315 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 316 #endif /* INVARIANTS */ 317 318 #ifndef KN_HASHSIZE 319 #define KN_HASHSIZE 64 /* XXX should be tunable */ 320 #endif 321 322 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 323 324 static int 325 filt_nullattach(struct knote *kn) 326 { 327 328 return (ENXIO); 329 }; 330 331 struct filterops null_filtops = { 332 .f_isfd = 0, 333 .f_attach = filt_nullattach, 334 }; 335 336 /* XXX - make SYSINIT to add these, and move into respective modules. */ 337 extern struct filterops sig_filtops; 338 extern struct filterops fs_filtops; 339 340 /* 341 * Table for for all system-defined filters. 342 */ 343 static struct mtx filterops_lock; 344 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 345 MTX_DEF); 346 static struct { 347 struct filterops *for_fop; 348 int for_nolock; 349 int for_refcnt; 350 } sysfilt_ops[EVFILT_SYSCOUNT] = { 351 { &file_filtops, 1 }, /* EVFILT_READ */ 352 { &file_filtops, 1 }, /* EVFILT_WRITE */ 353 { &null_filtops }, /* EVFILT_AIO */ 354 { &file_filtops, 1 }, /* EVFILT_VNODE */ 355 { &proc_filtops, 1 }, /* EVFILT_PROC */ 356 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 357 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 358 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 359 { &fs_filtops, 1 }, /* EVFILT_FS */ 360 { &null_filtops }, /* EVFILT_LIO */ 361 { &user_filtops, 1 }, /* EVFILT_USER */ 362 { &null_filtops }, /* EVFILT_SENDFILE */ 363 { &file_filtops, 1 }, /* EVFILT_EMPTY */ 364 }; 365 366 /* 367 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 368 * method. 369 */ 370 static int 371 filt_fileattach(struct knote *kn) 372 { 373 374 return (fo_kqfilter(kn->kn_fp, kn)); 375 } 376 377 /*ARGSUSED*/ 378 static int 379 kqueue_kqfilter(struct file *fp, struct knote *kn) 380 { 381 struct kqueue *kq = kn->kn_fp->f_data; 382 383 if (kn->kn_filter != EVFILT_READ) 384 return (EINVAL); 385 386 kn->kn_status |= KN_KQUEUE; 387 kn->kn_fop = &kqread_filtops; 388 knlist_add(&kq->kq_sel.si_note, kn, 0); 389 390 return (0); 391 } 392 393 static void 394 filt_kqdetach(struct knote *kn) 395 { 396 struct kqueue *kq = kn->kn_fp->f_data; 397 398 knlist_remove(&kq->kq_sel.si_note, kn, 0); 399 } 400 401 /*ARGSUSED*/ 402 static int 403 filt_kqueue(struct knote *kn, long hint) 404 { 405 struct kqueue *kq = kn->kn_fp->f_data; 406 407 kn->kn_data = kq->kq_count; 408 return (kn->kn_data > 0); 409 } 410 411 /* XXX - move to kern_proc.c? */ 412 static int 413 filt_procattach(struct knote *kn) 414 { 415 struct proc *p; 416 int error; 417 bool exiting, immediate; 418 419 exiting = immediate = false; 420 if (kn->kn_sfflags & NOTE_EXIT) 421 p = pfind_any(kn->kn_id); 422 else 423 p = pfind(kn->kn_id); 424 if (p == NULL) 425 return (ESRCH); 426 if (p->p_flag & P_WEXIT) 427 exiting = true; 428 429 if ((error = p_cansee(curthread, p))) { 430 PROC_UNLOCK(p); 431 return (error); 432 } 433 434 kn->kn_ptr.p_proc = p; 435 kn->kn_flags |= EV_CLEAR; /* automatically set */ 436 437 /* 438 * Internal flag indicating registration done by kernel for the 439 * purposes of getting a NOTE_CHILD notification. 440 */ 441 if (kn->kn_flags & EV_FLAG2) { 442 kn->kn_flags &= ~EV_FLAG2; 443 kn->kn_data = kn->kn_sdata; /* ppid */ 444 kn->kn_fflags = NOTE_CHILD; 445 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK); 446 immediate = true; /* Force immediate activation of child note. */ 447 } 448 /* 449 * Internal flag indicating registration done by kernel (for other than 450 * NOTE_CHILD). 451 */ 452 if (kn->kn_flags & EV_FLAG1) { 453 kn->kn_flags &= ~EV_FLAG1; 454 } 455 456 knlist_add(p->p_klist, kn, 1); 457 458 /* 459 * Immediately activate any child notes or, in the case of a zombie 460 * target process, exit notes. The latter is necessary to handle the 461 * case where the target process, e.g. a child, dies before the kevent 462 * is registered. 463 */ 464 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT))) 465 KNOTE_ACTIVATE(kn, 0); 466 467 PROC_UNLOCK(p); 468 469 return (0); 470 } 471 472 /* 473 * The knote may be attached to a different process, which may exit, 474 * leaving nothing for the knote to be attached to. So when the process 475 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 476 * it will be deleted when read out. However, as part of the knote deletion, 477 * this routine is called, so a check is needed to avoid actually performing 478 * a detach, because the original process does not exist any more. 479 */ 480 /* XXX - move to kern_proc.c? */ 481 static void 482 filt_procdetach(struct knote *kn) 483 { 484 485 knlist_remove(kn->kn_knlist, kn, 0); 486 kn->kn_ptr.p_proc = NULL; 487 } 488 489 /* XXX - move to kern_proc.c? */ 490 static int 491 filt_proc(struct knote *kn, long hint) 492 { 493 struct proc *p; 494 u_int event; 495 496 p = kn->kn_ptr.p_proc; 497 if (p == NULL) /* already activated, from attach filter */ 498 return (0); 499 500 /* Mask off extra data. */ 501 event = (u_int)hint & NOTE_PCTRLMASK; 502 503 /* If the user is interested in this event, record it. */ 504 if (kn->kn_sfflags & event) 505 kn->kn_fflags |= event; 506 507 /* Process is gone, so flag the event as finished. */ 508 if (event == NOTE_EXIT) { 509 kn->kn_flags |= EV_EOF | EV_ONESHOT; 510 kn->kn_ptr.p_proc = NULL; 511 if (kn->kn_fflags & NOTE_EXIT) 512 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 513 if (kn->kn_fflags == 0) 514 kn->kn_flags |= EV_DROP; 515 return (1); 516 } 517 518 return (kn->kn_fflags != 0); 519 } 520 521 /* 522 * Called when the process forked. It mostly does the same as the 523 * knote(), activating all knotes registered to be activated when the 524 * process forked. Additionally, for each knote attached to the 525 * parent, check whether user wants to track the new process. If so 526 * attach a new knote to it, and immediately report an event with the 527 * child's pid. 528 */ 529 void 530 knote_fork(struct knlist *list, int pid) 531 { 532 struct kqueue *kq; 533 struct knote *kn; 534 struct kevent kev; 535 int error; 536 537 MPASS(list != NULL); 538 KNL_ASSERT_LOCKED(list); 539 if (SLIST_EMPTY(&list->kl_list)) 540 return; 541 542 memset(&kev, 0, sizeof(kev)); 543 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 544 kq = kn->kn_kq; 545 KQ_LOCK(kq); 546 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 547 KQ_UNLOCK(kq); 548 continue; 549 } 550 551 /* 552 * The same as knote(), activate the event. 553 */ 554 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 555 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 556 KNOTE_ACTIVATE(kn, 1); 557 KQ_UNLOCK(kq); 558 continue; 559 } 560 561 /* 562 * The NOTE_TRACK case. In addition to the activation 563 * of the event, we need to register new events to 564 * track the child. Drop the locks in preparation for 565 * the call to kqueue_register(). 566 */ 567 kn_enter_flux(kn); 568 KQ_UNLOCK(kq); 569 list->kl_unlock(list->kl_lockarg); 570 571 /* 572 * Activate existing knote and register tracking knotes with 573 * new process. 574 * 575 * First register a knote to get just the child notice. This 576 * must be a separate note from a potential NOTE_EXIT 577 * notification since both NOTE_CHILD and NOTE_EXIT are defined 578 * to use the data field (in conflicting ways). 579 */ 580 kev.ident = pid; 581 kev.filter = kn->kn_filter; 582 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | 583 EV_FLAG2; 584 kev.fflags = kn->kn_sfflags; 585 kev.data = kn->kn_id; /* parent */ 586 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 587 error = kqueue_register(kq, &kev, NULL, M_NOWAIT); 588 if (error) 589 kn->kn_fflags |= NOTE_TRACKERR; 590 591 /* 592 * Then register another knote to track other potential events 593 * from the new process. 594 */ 595 kev.ident = pid; 596 kev.filter = kn->kn_filter; 597 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 598 kev.fflags = kn->kn_sfflags; 599 kev.data = kn->kn_id; /* parent */ 600 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 601 error = kqueue_register(kq, &kev, NULL, M_NOWAIT); 602 if (error) 603 kn->kn_fflags |= NOTE_TRACKERR; 604 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 605 KNOTE_ACTIVATE(kn, 0); 606 list->kl_lock(list->kl_lockarg); 607 KQ_LOCK(kq); 608 kn_leave_flux(kn); 609 KQ_UNLOCK_FLUX(kq); 610 } 611 } 612 613 /* 614 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 615 * interval timer support code. 616 */ 617 618 #define NOTE_TIMER_PRECMASK \ 619 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS) 620 621 static sbintime_t 622 timer2sbintime(int64_t data, int flags) 623 { 624 int64_t secs; 625 626 /* 627 * Macros for converting to the fractional second portion of an 628 * sbintime_t using 64bit multiplication to improve precision. 629 */ 630 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 631 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 632 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 633 switch (flags & NOTE_TIMER_PRECMASK) { 634 case NOTE_SECONDS: 635 #ifdef __LP64__ 636 if (data > (SBT_MAX / SBT_1S)) 637 return (SBT_MAX); 638 #endif 639 return ((sbintime_t)data << 32); 640 case NOTE_MSECONDS: /* FALLTHROUGH */ 641 case 0: 642 if (data >= 1000) { 643 secs = data / 1000; 644 #ifdef __LP64__ 645 if (secs > (SBT_MAX / SBT_1S)) 646 return (SBT_MAX); 647 #endif 648 return (secs << 32 | MS_TO_SBT(data % 1000)); 649 } 650 return (MS_TO_SBT(data)); 651 case NOTE_USECONDS: 652 if (data >= 1000000) { 653 secs = data / 1000000; 654 #ifdef __LP64__ 655 if (secs > (SBT_MAX / SBT_1S)) 656 return (SBT_MAX); 657 #endif 658 return (secs << 32 | US_TO_SBT(data % 1000000)); 659 } 660 return (US_TO_SBT(data)); 661 case NOTE_NSECONDS: 662 if (data >= 1000000000) { 663 secs = data / 1000000000; 664 #ifdef __LP64__ 665 if (secs > (SBT_MAX / SBT_1S)) 666 return (SBT_MAX); 667 #endif 668 return (secs << 32 | NS_TO_SBT(data % 1000000000)); 669 } 670 return (NS_TO_SBT(data)); 671 default: 672 break; 673 } 674 return (-1); 675 } 676 677 struct kq_timer_cb_data { 678 struct callout c; 679 sbintime_t next; /* next timer event fires at */ 680 sbintime_t to; /* precalculated timer period, 0 for abs */ 681 }; 682 683 static void 684 filt_timerexpire(void *knx) 685 { 686 struct knote *kn; 687 struct kq_timer_cb_data *kc; 688 689 kn = knx; 690 kn->kn_data++; 691 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 692 693 if ((kn->kn_flags & EV_ONESHOT) != 0) 694 return; 695 kc = kn->kn_ptr.p_v; 696 if (kc->to == 0) 697 return; 698 kc->next += kc->to; 699 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 700 PCPU_GET(cpuid), C_ABSOLUTE); 701 } 702 703 /* 704 * data contains amount of time to sleep 705 */ 706 static int 707 filt_timervalidate(struct knote *kn, sbintime_t *to) 708 { 709 struct bintime bt; 710 sbintime_t sbt; 711 712 if (kn->kn_sdata < 0) 713 return (EINVAL); 714 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 715 kn->kn_sdata = 1; 716 /* 717 * The only fflags values supported are the timer unit 718 * (precision) and the absolute time indicator. 719 */ 720 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0) 721 return (EINVAL); 722 723 *to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 724 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 725 getboottimebin(&bt); 726 sbt = bttosbt(bt); 727 *to -= sbt; 728 } 729 if (*to < 0) 730 return (EINVAL); 731 return (0); 732 } 733 734 static int 735 filt_timerattach(struct knote *kn) 736 { 737 struct kq_timer_cb_data *kc; 738 sbintime_t to; 739 unsigned int ncallouts; 740 int error; 741 742 error = filt_timervalidate(kn, &to); 743 if (error != 0) 744 return (error); 745 746 do { 747 ncallouts = kq_ncallouts; 748 if (ncallouts >= kq_calloutmax) 749 return (ENOMEM); 750 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 751 752 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0) 753 kn->kn_flags |= EV_CLEAR; /* automatically set */ 754 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 755 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 756 callout_init(&kc->c, 1); 757 filt_timerstart(kn, to); 758 759 return (0); 760 } 761 762 static void 763 filt_timerstart(struct knote *kn, sbintime_t to) 764 { 765 struct kq_timer_cb_data *kc; 766 767 kc = kn->kn_ptr.p_v; 768 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 769 kc->next = to; 770 kc->to = 0; 771 } else { 772 kc->next = to + sbinuptime(); 773 kc->to = to; 774 } 775 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 776 PCPU_GET(cpuid), C_ABSOLUTE); 777 } 778 779 static void 780 filt_timerdetach(struct knote *kn) 781 { 782 struct kq_timer_cb_data *kc; 783 unsigned int old __unused; 784 785 kc = kn->kn_ptr.p_v; 786 callout_drain(&kc->c); 787 free(kc, M_KQUEUE); 788 old = atomic_fetchadd_int(&kq_ncallouts, -1); 789 KASSERT(old > 0, ("Number of callouts cannot become negative")); 790 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 791 } 792 793 static void 794 filt_timertouch(struct knote *kn, struct kevent *kev, u_long type) 795 { 796 struct kq_timer_cb_data *kc; 797 struct kqueue *kq; 798 sbintime_t to; 799 int error; 800 801 switch (type) { 802 case EVENT_REGISTER: 803 /* Handle re-added timers that update data/fflags */ 804 if (kev->flags & EV_ADD) { 805 kc = kn->kn_ptr.p_v; 806 807 /* Drain any existing callout. */ 808 callout_drain(&kc->c); 809 810 /* Throw away any existing undelivered record 811 * of the timer expiration. This is done under 812 * the presumption that if a process is 813 * re-adding this timer with new parameters, 814 * it is no longer interested in what may have 815 * happened under the old parameters. If it is 816 * interested, it can wait for the expiration, 817 * delete the old timer definition, and then 818 * add the new one. 819 * 820 * This has to be done while the kq is locked: 821 * - if enqueued, dequeue 822 * - make it no longer active 823 * - clear the count of expiration events 824 */ 825 kq = kn->kn_kq; 826 KQ_LOCK(kq); 827 if (kn->kn_status & KN_QUEUED) 828 knote_dequeue(kn); 829 830 kn->kn_status &= ~KN_ACTIVE; 831 kn->kn_data = 0; 832 KQ_UNLOCK(kq); 833 834 /* Reschedule timer based on new data/fflags */ 835 kn->kn_sfflags = kev->fflags; 836 kn->kn_sdata = kev->data; 837 error = filt_timervalidate(kn, &to); 838 if (error != 0) { 839 kn->kn_flags |= EV_ERROR; 840 kn->kn_data = error; 841 } else 842 filt_timerstart(kn, to); 843 } 844 break; 845 846 case EVENT_PROCESS: 847 *kev = kn->kn_kevent; 848 if (kn->kn_flags & EV_CLEAR) { 849 kn->kn_data = 0; 850 kn->kn_fflags = 0; 851 } 852 break; 853 854 default: 855 panic("filt_timertouch() - invalid type (%ld)", type); 856 break; 857 } 858 } 859 860 static int 861 filt_timer(struct knote *kn, long hint) 862 { 863 864 return (kn->kn_data != 0); 865 } 866 867 static int 868 filt_userattach(struct knote *kn) 869 { 870 871 /* 872 * EVFILT_USER knotes are not attached to anything in the kernel. 873 */ 874 kn->kn_hook = NULL; 875 if (kn->kn_fflags & NOTE_TRIGGER) 876 kn->kn_hookid = 1; 877 else 878 kn->kn_hookid = 0; 879 return (0); 880 } 881 882 static void 883 filt_userdetach(__unused struct knote *kn) 884 { 885 886 /* 887 * EVFILT_USER knotes are not attached to anything in the kernel. 888 */ 889 } 890 891 static int 892 filt_user(struct knote *kn, __unused long hint) 893 { 894 895 return (kn->kn_hookid); 896 } 897 898 static void 899 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 900 { 901 u_int ffctrl; 902 903 switch (type) { 904 case EVENT_REGISTER: 905 if (kev->fflags & NOTE_TRIGGER) 906 kn->kn_hookid = 1; 907 908 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 909 kev->fflags &= NOTE_FFLAGSMASK; 910 switch (ffctrl) { 911 case NOTE_FFNOP: 912 break; 913 914 case NOTE_FFAND: 915 kn->kn_sfflags &= kev->fflags; 916 break; 917 918 case NOTE_FFOR: 919 kn->kn_sfflags |= kev->fflags; 920 break; 921 922 case NOTE_FFCOPY: 923 kn->kn_sfflags = kev->fflags; 924 break; 925 926 default: 927 /* XXX Return error? */ 928 break; 929 } 930 kn->kn_sdata = kev->data; 931 if (kev->flags & EV_CLEAR) { 932 kn->kn_hookid = 0; 933 kn->kn_data = 0; 934 kn->kn_fflags = 0; 935 } 936 break; 937 938 case EVENT_PROCESS: 939 *kev = kn->kn_kevent; 940 kev->fflags = kn->kn_sfflags; 941 kev->data = kn->kn_sdata; 942 if (kn->kn_flags & EV_CLEAR) { 943 kn->kn_hookid = 0; 944 kn->kn_data = 0; 945 kn->kn_fflags = 0; 946 } 947 break; 948 949 default: 950 panic("filt_usertouch() - invalid type (%ld)", type); 951 break; 952 } 953 } 954 955 int 956 sys_kqueue(struct thread *td, struct kqueue_args *uap) 957 { 958 959 return (kern_kqueue(td, 0, NULL)); 960 } 961 962 static void 963 kqueue_init(struct kqueue *kq) 964 { 965 966 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 967 TAILQ_INIT(&kq->kq_head); 968 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 969 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 970 } 971 972 int 973 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 974 { 975 struct filedesc *fdp; 976 struct kqueue *kq; 977 struct file *fp; 978 struct ucred *cred; 979 int fd, error; 980 981 fdp = td->td_proc->p_fd; 982 cred = td->td_ucred; 983 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 984 return (ENOMEM); 985 986 error = falloc_caps(td, &fp, &fd, flags, fcaps); 987 if (error != 0) { 988 chgkqcnt(cred->cr_ruidinfo, -1, 0); 989 return (error); 990 } 991 992 /* An extra reference on `fp' has been held for us by falloc(). */ 993 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 994 kqueue_init(kq); 995 kq->kq_fdp = fdp; 996 kq->kq_cred = crhold(cred); 997 998 FILEDESC_XLOCK(fdp); 999 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 1000 FILEDESC_XUNLOCK(fdp); 1001 1002 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 1003 fdrop(fp, td); 1004 1005 td->td_retval[0] = fd; 1006 return (0); 1007 } 1008 1009 struct g_kevent_args { 1010 int fd; 1011 void *changelist; 1012 int nchanges; 1013 void *eventlist; 1014 int nevents; 1015 const struct timespec *timeout; 1016 }; 1017 1018 int 1019 sys_kevent(struct thread *td, struct kevent_args *uap) 1020 { 1021 struct kevent_copyops k_ops = { 1022 .arg = uap, 1023 .k_copyout = kevent_copyout, 1024 .k_copyin = kevent_copyin, 1025 .kevent_size = sizeof(struct kevent), 1026 }; 1027 struct g_kevent_args gk_args = { 1028 .fd = uap->fd, 1029 .changelist = uap->changelist, 1030 .nchanges = uap->nchanges, 1031 .eventlist = uap->eventlist, 1032 .nevents = uap->nevents, 1033 .timeout = uap->timeout, 1034 }; 1035 1036 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent")); 1037 } 1038 1039 static int 1040 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap, 1041 struct kevent_copyops *k_ops, const char *struct_name) 1042 { 1043 struct timespec ts, *tsp; 1044 #ifdef KTRACE 1045 struct kevent *eventlist = uap->eventlist; 1046 #endif 1047 int error; 1048 1049 if (uap->timeout != NULL) { 1050 error = copyin(uap->timeout, &ts, sizeof(ts)); 1051 if (error) 1052 return (error); 1053 tsp = &ts; 1054 } else 1055 tsp = NULL; 1056 1057 #ifdef KTRACE 1058 if (KTRPOINT(td, KTR_STRUCT_ARRAY)) 1059 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist, 1060 uap->nchanges, k_ops->kevent_size); 1061 #endif 1062 1063 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 1064 k_ops, tsp); 1065 1066 #ifdef KTRACE 1067 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY)) 1068 ktrstructarray(struct_name, UIO_USERSPACE, eventlist, 1069 td->td_retval[0], k_ops->kevent_size); 1070 #endif 1071 1072 return (error); 1073 } 1074 1075 /* 1076 * Copy 'count' items into the destination list pointed to by uap->eventlist. 1077 */ 1078 static int 1079 kevent_copyout(void *arg, struct kevent *kevp, int count) 1080 { 1081 struct kevent_args *uap; 1082 int error; 1083 1084 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1085 uap = (struct kevent_args *)arg; 1086 1087 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 1088 if (error == 0) 1089 uap->eventlist += count; 1090 return (error); 1091 } 1092 1093 /* 1094 * Copy 'count' items from the list pointed to by uap->changelist. 1095 */ 1096 static int 1097 kevent_copyin(void *arg, struct kevent *kevp, int count) 1098 { 1099 struct kevent_args *uap; 1100 int error; 1101 1102 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1103 uap = (struct kevent_args *)arg; 1104 1105 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 1106 if (error == 0) 1107 uap->changelist += count; 1108 return (error); 1109 } 1110 1111 #ifdef COMPAT_FREEBSD11 1112 static int 1113 kevent11_copyout(void *arg, struct kevent *kevp, int count) 1114 { 1115 struct freebsd11_kevent_args *uap; 1116 struct kevent_freebsd11 kev11; 1117 int error, i; 1118 1119 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1120 uap = (struct freebsd11_kevent_args *)arg; 1121 1122 for (i = 0; i < count; i++) { 1123 kev11.ident = kevp->ident; 1124 kev11.filter = kevp->filter; 1125 kev11.flags = kevp->flags; 1126 kev11.fflags = kevp->fflags; 1127 kev11.data = kevp->data; 1128 kev11.udata = kevp->udata; 1129 error = copyout(&kev11, uap->eventlist, sizeof(kev11)); 1130 if (error != 0) 1131 break; 1132 uap->eventlist++; 1133 kevp++; 1134 } 1135 return (error); 1136 } 1137 1138 /* 1139 * Copy 'count' items from the list pointed to by uap->changelist. 1140 */ 1141 static int 1142 kevent11_copyin(void *arg, struct kevent *kevp, int count) 1143 { 1144 struct freebsd11_kevent_args *uap; 1145 struct kevent_freebsd11 kev11; 1146 int error, i; 1147 1148 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1149 uap = (struct freebsd11_kevent_args *)arg; 1150 1151 for (i = 0; i < count; i++) { 1152 error = copyin(uap->changelist, &kev11, sizeof(kev11)); 1153 if (error != 0) 1154 break; 1155 kevp->ident = kev11.ident; 1156 kevp->filter = kev11.filter; 1157 kevp->flags = kev11.flags; 1158 kevp->fflags = kev11.fflags; 1159 kevp->data = (uintptr_t)kev11.data; 1160 kevp->udata = kev11.udata; 1161 bzero(&kevp->ext, sizeof(kevp->ext)); 1162 uap->changelist++; 1163 kevp++; 1164 } 1165 return (error); 1166 } 1167 1168 int 1169 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap) 1170 { 1171 struct kevent_copyops k_ops = { 1172 .arg = uap, 1173 .k_copyout = kevent11_copyout, 1174 .k_copyin = kevent11_copyin, 1175 .kevent_size = sizeof(struct kevent_freebsd11), 1176 }; 1177 struct g_kevent_args gk_args = { 1178 .fd = uap->fd, 1179 .changelist = uap->changelist, 1180 .nchanges = uap->nchanges, 1181 .eventlist = uap->eventlist, 1182 .nevents = uap->nevents, 1183 .timeout = uap->timeout, 1184 }; 1185 1186 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11")); 1187 } 1188 #endif 1189 1190 int 1191 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1192 struct kevent_copyops *k_ops, const struct timespec *timeout) 1193 { 1194 cap_rights_t rights; 1195 struct file *fp; 1196 int error; 1197 1198 cap_rights_init_zero(&rights); 1199 if (nchanges > 0) 1200 cap_rights_set_one(&rights, CAP_KQUEUE_CHANGE); 1201 if (nevents > 0) 1202 cap_rights_set_one(&rights, CAP_KQUEUE_EVENT); 1203 error = fget(td, fd, &rights, &fp); 1204 if (error != 0) 1205 return (error); 1206 1207 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1208 fdrop(fp, td); 1209 1210 return (error); 1211 } 1212 1213 static int 1214 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1215 struct kevent_copyops *k_ops, const struct timespec *timeout) 1216 { 1217 struct kevent keva[KQ_NEVENTS]; 1218 struct kevent *kevp, *changes; 1219 int i, n, nerrors, error; 1220 1221 nerrors = 0; 1222 while (nchanges > 0) { 1223 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1224 error = k_ops->k_copyin(k_ops->arg, keva, n); 1225 if (error) 1226 return (error); 1227 changes = keva; 1228 for (i = 0; i < n; i++) { 1229 kevp = &changes[i]; 1230 if (!kevp->filter) 1231 continue; 1232 kevp->flags &= ~EV_SYSFLAGS; 1233 error = kqueue_register(kq, kevp, td, M_WAITOK); 1234 if (error || (kevp->flags & EV_RECEIPT)) { 1235 if (nevents == 0) 1236 return (error); 1237 kevp->flags = EV_ERROR; 1238 kevp->data = error; 1239 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1240 nevents--; 1241 nerrors++; 1242 } 1243 } 1244 nchanges -= n; 1245 } 1246 if (nerrors) { 1247 td->td_retval[0] = nerrors; 1248 return (0); 1249 } 1250 1251 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1252 } 1253 1254 int 1255 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1256 struct kevent_copyops *k_ops, const struct timespec *timeout) 1257 { 1258 struct kqueue *kq; 1259 int error; 1260 1261 error = kqueue_acquire(fp, &kq); 1262 if (error != 0) 1263 return (error); 1264 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1265 kqueue_release(kq, 0); 1266 return (error); 1267 } 1268 1269 /* 1270 * Performs a kevent() call on a temporarily created kqueue. This can be 1271 * used to perform one-shot polling, similar to poll() and select(). 1272 */ 1273 int 1274 kern_kevent_anonymous(struct thread *td, int nevents, 1275 struct kevent_copyops *k_ops) 1276 { 1277 struct kqueue kq = {}; 1278 int error; 1279 1280 kqueue_init(&kq); 1281 kq.kq_refcnt = 1; 1282 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1283 kqueue_drain(&kq, td); 1284 kqueue_destroy(&kq); 1285 return (error); 1286 } 1287 1288 int 1289 kqueue_add_filteropts(int filt, struct filterops *filtops) 1290 { 1291 int error; 1292 1293 error = 0; 1294 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1295 printf( 1296 "trying to add a filterop that is out of range: %d is beyond %d\n", 1297 ~filt, EVFILT_SYSCOUNT); 1298 return EINVAL; 1299 } 1300 mtx_lock(&filterops_lock); 1301 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1302 sysfilt_ops[~filt].for_fop != NULL) 1303 error = EEXIST; 1304 else { 1305 sysfilt_ops[~filt].for_fop = filtops; 1306 sysfilt_ops[~filt].for_refcnt = 0; 1307 } 1308 mtx_unlock(&filterops_lock); 1309 1310 return (error); 1311 } 1312 1313 int 1314 kqueue_del_filteropts(int filt) 1315 { 1316 int error; 1317 1318 error = 0; 1319 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1320 return EINVAL; 1321 1322 mtx_lock(&filterops_lock); 1323 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1324 sysfilt_ops[~filt].for_fop == NULL) 1325 error = EINVAL; 1326 else if (sysfilt_ops[~filt].for_refcnt != 0) 1327 error = EBUSY; 1328 else { 1329 sysfilt_ops[~filt].for_fop = &null_filtops; 1330 sysfilt_ops[~filt].for_refcnt = 0; 1331 } 1332 mtx_unlock(&filterops_lock); 1333 1334 return error; 1335 } 1336 1337 static struct filterops * 1338 kqueue_fo_find(int filt) 1339 { 1340 1341 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1342 return NULL; 1343 1344 if (sysfilt_ops[~filt].for_nolock) 1345 return sysfilt_ops[~filt].for_fop; 1346 1347 mtx_lock(&filterops_lock); 1348 sysfilt_ops[~filt].for_refcnt++; 1349 if (sysfilt_ops[~filt].for_fop == NULL) 1350 sysfilt_ops[~filt].for_fop = &null_filtops; 1351 mtx_unlock(&filterops_lock); 1352 1353 return sysfilt_ops[~filt].for_fop; 1354 } 1355 1356 static void 1357 kqueue_fo_release(int filt) 1358 { 1359 1360 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1361 return; 1362 1363 if (sysfilt_ops[~filt].for_nolock) 1364 return; 1365 1366 mtx_lock(&filterops_lock); 1367 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1368 ("filter object refcount not valid on release")); 1369 sysfilt_ops[~filt].for_refcnt--; 1370 mtx_unlock(&filterops_lock); 1371 } 1372 1373 /* 1374 * A ref to kq (obtained via kqueue_acquire) must be held. 1375 */ 1376 static int 1377 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, 1378 int mflag) 1379 { 1380 struct filterops *fops; 1381 struct file *fp; 1382 struct knote *kn, *tkn; 1383 struct knlist *knl; 1384 int error, filt, event; 1385 int haskqglobal, filedesc_unlock; 1386 1387 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1388 return (EINVAL); 1389 1390 fp = NULL; 1391 kn = NULL; 1392 knl = NULL; 1393 error = 0; 1394 haskqglobal = 0; 1395 filedesc_unlock = 0; 1396 1397 filt = kev->filter; 1398 fops = kqueue_fo_find(filt); 1399 if (fops == NULL) 1400 return EINVAL; 1401 1402 if (kev->flags & EV_ADD) { 1403 /* 1404 * Prevent waiting with locks. Non-sleepable 1405 * allocation failures are handled in the loop, only 1406 * if the spare knote appears to be actually required. 1407 */ 1408 tkn = knote_alloc(mflag); 1409 } else { 1410 tkn = NULL; 1411 } 1412 1413 findkn: 1414 if (fops->f_isfd) { 1415 KASSERT(td != NULL, ("td is NULL")); 1416 if (kev->ident > INT_MAX) 1417 error = EBADF; 1418 else 1419 error = fget(td, kev->ident, &cap_event_rights, &fp); 1420 if (error) 1421 goto done; 1422 1423 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1424 kev->ident, M_NOWAIT) != 0) { 1425 /* try again */ 1426 fdrop(fp, td); 1427 fp = NULL; 1428 error = kqueue_expand(kq, fops, kev->ident, mflag); 1429 if (error) 1430 goto done; 1431 goto findkn; 1432 } 1433 1434 if (fp->f_type == DTYPE_KQUEUE) { 1435 /* 1436 * If we add some intelligence about what we are doing, 1437 * we should be able to support events on ourselves. 1438 * We need to know when we are doing this to prevent 1439 * getting both the knlist lock and the kq lock since 1440 * they are the same thing. 1441 */ 1442 if (fp->f_data == kq) { 1443 error = EINVAL; 1444 goto done; 1445 } 1446 1447 /* 1448 * Pre-lock the filedesc before the global 1449 * lock mutex, see the comment in 1450 * kqueue_close(). 1451 */ 1452 FILEDESC_XLOCK(td->td_proc->p_fd); 1453 filedesc_unlock = 1; 1454 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1455 } 1456 1457 KQ_LOCK(kq); 1458 if (kev->ident < kq->kq_knlistsize) { 1459 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1460 if (kev->filter == kn->kn_filter) 1461 break; 1462 } 1463 } else { 1464 if ((kev->flags & EV_ADD) == EV_ADD) { 1465 error = kqueue_expand(kq, fops, kev->ident, mflag); 1466 if (error != 0) 1467 goto done; 1468 } 1469 1470 KQ_LOCK(kq); 1471 1472 /* 1473 * If possible, find an existing knote to use for this kevent. 1474 */ 1475 if (kev->filter == EVFILT_PROC && 1476 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1477 /* This is an internal creation of a process tracking 1478 * note. Don't attempt to coalesce this with an 1479 * existing note. 1480 */ 1481 ; 1482 } else if (kq->kq_knhashmask != 0) { 1483 struct klist *list; 1484 1485 list = &kq->kq_knhash[ 1486 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1487 SLIST_FOREACH(kn, list, kn_link) 1488 if (kev->ident == kn->kn_id && 1489 kev->filter == kn->kn_filter) 1490 break; 1491 } 1492 } 1493 1494 /* knote is in the process of changing, wait for it to stabilize. */ 1495 if (kn != NULL && kn_in_flux(kn)) { 1496 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1497 if (filedesc_unlock) { 1498 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1499 filedesc_unlock = 0; 1500 } 1501 kq->kq_state |= KQ_FLUXWAIT; 1502 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1503 if (fp != NULL) { 1504 fdrop(fp, td); 1505 fp = NULL; 1506 } 1507 goto findkn; 1508 } 1509 1510 /* 1511 * kn now contains the matching knote, or NULL if no match 1512 */ 1513 if (kn == NULL) { 1514 if (kev->flags & EV_ADD) { 1515 kn = tkn; 1516 tkn = NULL; 1517 if (kn == NULL) { 1518 KQ_UNLOCK(kq); 1519 error = ENOMEM; 1520 goto done; 1521 } 1522 kn->kn_fp = fp; 1523 kn->kn_kq = kq; 1524 kn->kn_fop = fops; 1525 /* 1526 * apply reference counts to knote structure, and 1527 * do not release it at the end of this routine. 1528 */ 1529 fops = NULL; 1530 fp = NULL; 1531 1532 kn->kn_sfflags = kev->fflags; 1533 kn->kn_sdata = kev->data; 1534 kev->fflags = 0; 1535 kev->data = 0; 1536 kn->kn_kevent = *kev; 1537 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1538 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1539 kn->kn_status = KN_DETACHED; 1540 if ((kev->flags & EV_DISABLE) != 0) 1541 kn->kn_status |= KN_DISABLED; 1542 kn_enter_flux(kn); 1543 1544 error = knote_attach(kn, kq); 1545 KQ_UNLOCK(kq); 1546 if (error != 0) { 1547 tkn = kn; 1548 goto done; 1549 } 1550 1551 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1552 knote_drop_detached(kn, td); 1553 goto done; 1554 } 1555 knl = kn_list_lock(kn); 1556 goto done_ev_add; 1557 } else { 1558 /* No matching knote and the EV_ADD flag is not set. */ 1559 KQ_UNLOCK(kq); 1560 error = ENOENT; 1561 goto done; 1562 } 1563 } 1564 1565 if (kev->flags & EV_DELETE) { 1566 kn_enter_flux(kn); 1567 KQ_UNLOCK(kq); 1568 knote_drop(kn, td); 1569 goto done; 1570 } 1571 1572 if (kev->flags & EV_FORCEONESHOT) { 1573 kn->kn_flags |= EV_ONESHOT; 1574 KNOTE_ACTIVATE(kn, 1); 1575 } 1576 1577 if ((kev->flags & EV_ENABLE) != 0) 1578 kn->kn_status &= ~KN_DISABLED; 1579 else if ((kev->flags & EV_DISABLE) != 0) 1580 kn->kn_status |= KN_DISABLED; 1581 1582 /* 1583 * The user may change some filter values after the initial EV_ADD, 1584 * but doing so will not reset any filter which has already been 1585 * triggered. 1586 */ 1587 kn->kn_status |= KN_SCAN; 1588 kn_enter_flux(kn); 1589 KQ_UNLOCK(kq); 1590 knl = kn_list_lock(kn); 1591 kn->kn_kevent.udata = kev->udata; 1592 if (!fops->f_isfd && fops->f_touch != NULL) { 1593 fops->f_touch(kn, kev, EVENT_REGISTER); 1594 } else { 1595 kn->kn_sfflags = kev->fflags; 1596 kn->kn_sdata = kev->data; 1597 } 1598 1599 done_ev_add: 1600 /* 1601 * We can get here with kn->kn_knlist == NULL. This can happen when 1602 * the initial attach event decides that the event is "completed" 1603 * already, e.g., filt_procattach() is called on a zombie process. It 1604 * will call filt_proc() which will remove it from the list, and NULL 1605 * kn_knlist. 1606 * 1607 * KN_DISABLED will be stable while the knote is in flux, so the 1608 * unlocked read will not race with an update. 1609 */ 1610 if ((kn->kn_status & KN_DISABLED) == 0) 1611 event = kn->kn_fop->f_event(kn, 0); 1612 else 1613 event = 0; 1614 1615 KQ_LOCK(kq); 1616 if (event) 1617 kn->kn_status |= KN_ACTIVE; 1618 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1619 KN_ACTIVE) 1620 knote_enqueue(kn); 1621 kn->kn_status &= ~KN_SCAN; 1622 kn_leave_flux(kn); 1623 kn_list_unlock(knl); 1624 KQ_UNLOCK_FLUX(kq); 1625 1626 done: 1627 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1628 if (filedesc_unlock) 1629 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1630 if (fp != NULL) 1631 fdrop(fp, td); 1632 knote_free(tkn); 1633 if (fops != NULL) 1634 kqueue_fo_release(filt); 1635 return (error); 1636 } 1637 1638 static int 1639 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1640 { 1641 int error; 1642 struct kqueue *kq; 1643 1644 error = 0; 1645 1646 kq = fp->f_data; 1647 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1648 return (EBADF); 1649 *kqp = kq; 1650 KQ_LOCK(kq); 1651 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1652 KQ_UNLOCK(kq); 1653 return (EBADF); 1654 } 1655 kq->kq_refcnt++; 1656 KQ_UNLOCK(kq); 1657 1658 return error; 1659 } 1660 1661 static void 1662 kqueue_release(struct kqueue *kq, int locked) 1663 { 1664 if (locked) 1665 KQ_OWNED(kq); 1666 else 1667 KQ_LOCK(kq); 1668 kq->kq_refcnt--; 1669 if (kq->kq_refcnt == 1) 1670 wakeup(&kq->kq_refcnt); 1671 if (!locked) 1672 KQ_UNLOCK(kq); 1673 } 1674 1675 static void 1676 kqueue_schedtask(struct kqueue *kq) 1677 { 1678 1679 KQ_OWNED(kq); 1680 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1681 ("scheduling kqueue task while draining")); 1682 1683 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1684 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1685 kq->kq_state |= KQ_TASKSCHED; 1686 } 1687 } 1688 1689 /* 1690 * Expand the kq to make sure we have storage for fops/ident pair. 1691 * 1692 * Return 0 on success (or no work necessary), return errno on failure. 1693 */ 1694 static int 1695 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1696 int mflag) 1697 { 1698 struct klist *list, *tmp_knhash, *to_free; 1699 u_long tmp_knhashmask; 1700 int error, fd, size; 1701 1702 KQ_NOTOWNED(kq); 1703 1704 error = 0; 1705 to_free = NULL; 1706 if (fops->f_isfd) { 1707 fd = ident; 1708 if (kq->kq_knlistsize <= fd) { 1709 size = kq->kq_knlistsize; 1710 while (size <= fd) 1711 size += KQEXTENT; 1712 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1713 if (list == NULL) 1714 return ENOMEM; 1715 KQ_LOCK(kq); 1716 if ((kq->kq_state & KQ_CLOSING) != 0) { 1717 to_free = list; 1718 error = EBADF; 1719 } else if (kq->kq_knlistsize > fd) { 1720 to_free = list; 1721 } else { 1722 if (kq->kq_knlist != NULL) { 1723 bcopy(kq->kq_knlist, list, 1724 kq->kq_knlistsize * sizeof(*list)); 1725 to_free = kq->kq_knlist; 1726 kq->kq_knlist = NULL; 1727 } 1728 bzero((caddr_t)list + 1729 kq->kq_knlistsize * sizeof(*list), 1730 (size - kq->kq_knlistsize) * sizeof(*list)); 1731 kq->kq_knlistsize = size; 1732 kq->kq_knlist = list; 1733 } 1734 KQ_UNLOCK(kq); 1735 } 1736 } else { 1737 if (kq->kq_knhashmask == 0) { 1738 tmp_knhash = hashinit_flags(KN_HASHSIZE, M_KQUEUE, 1739 &tmp_knhashmask, (mflag & M_WAITOK) != 0 ? 1740 HASH_WAITOK : HASH_NOWAIT); 1741 if (tmp_knhash == NULL) 1742 return (ENOMEM); 1743 KQ_LOCK(kq); 1744 if ((kq->kq_state & KQ_CLOSING) != 0) { 1745 to_free = tmp_knhash; 1746 error = EBADF; 1747 } else if (kq->kq_knhashmask == 0) { 1748 kq->kq_knhash = tmp_knhash; 1749 kq->kq_knhashmask = tmp_knhashmask; 1750 } else { 1751 to_free = tmp_knhash; 1752 } 1753 KQ_UNLOCK(kq); 1754 } 1755 } 1756 free(to_free, M_KQUEUE); 1757 1758 KQ_NOTOWNED(kq); 1759 return (error); 1760 } 1761 1762 static void 1763 kqueue_task(void *arg, int pending) 1764 { 1765 struct kqueue *kq; 1766 int haskqglobal; 1767 1768 haskqglobal = 0; 1769 kq = arg; 1770 1771 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1772 KQ_LOCK(kq); 1773 1774 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1775 1776 kq->kq_state &= ~KQ_TASKSCHED; 1777 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1778 wakeup(&kq->kq_state); 1779 } 1780 KQ_UNLOCK(kq); 1781 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1782 } 1783 1784 /* 1785 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1786 * We treat KN_MARKER knotes as if they are in flux. 1787 */ 1788 static int 1789 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1790 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1791 { 1792 struct kevent *kevp; 1793 struct knote *kn, *marker; 1794 struct knlist *knl; 1795 sbintime_t asbt, rsbt; 1796 int count, error, haskqglobal, influx, nkev, touch; 1797 1798 count = maxevents; 1799 nkev = 0; 1800 error = 0; 1801 haskqglobal = 0; 1802 1803 if (maxevents == 0) 1804 goto done_nl; 1805 1806 rsbt = 0; 1807 if (tsp != NULL) { 1808 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1809 tsp->tv_nsec >= 1000000000) { 1810 error = EINVAL; 1811 goto done_nl; 1812 } 1813 if (timespecisset(tsp)) { 1814 if (tsp->tv_sec <= INT32_MAX) { 1815 rsbt = tstosbt(*tsp); 1816 if (TIMESEL(&asbt, rsbt)) 1817 asbt += tc_tick_sbt; 1818 if (asbt <= SBT_MAX - rsbt) 1819 asbt += rsbt; 1820 else 1821 asbt = 0; 1822 rsbt >>= tc_precexp; 1823 } else 1824 asbt = 0; 1825 } else 1826 asbt = -1; 1827 } else 1828 asbt = 0; 1829 marker = knote_alloc(M_WAITOK); 1830 marker->kn_status = KN_MARKER; 1831 KQ_LOCK(kq); 1832 1833 retry: 1834 kevp = keva; 1835 if (kq->kq_count == 0) { 1836 if (asbt == -1) { 1837 error = EWOULDBLOCK; 1838 } else { 1839 kq->kq_state |= KQ_SLEEP; 1840 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1841 "kqread", asbt, rsbt, C_ABSOLUTE); 1842 } 1843 if (error == 0) 1844 goto retry; 1845 /* don't restart after signals... */ 1846 if (error == ERESTART) 1847 error = EINTR; 1848 else if (error == EWOULDBLOCK) 1849 error = 0; 1850 goto done; 1851 } 1852 1853 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1854 influx = 0; 1855 while (count) { 1856 KQ_OWNED(kq); 1857 kn = TAILQ_FIRST(&kq->kq_head); 1858 1859 if ((kn->kn_status == KN_MARKER && kn != marker) || 1860 kn_in_flux(kn)) { 1861 if (influx) { 1862 influx = 0; 1863 KQ_FLUX_WAKEUP(kq); 1864 } 1865 kq->kq_state |= KQ_FLUXWAIT; 1866 error = msleep(kq, &kq->kq_lock, PSOCK, 1867 "kqflxwt", 0); 1868 continue; 1869 } 1870 1871 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1872 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1873 kn->kn_status &= ~KN_QUEUED; 1874 kq->kq_count--; 1875 continue; 1876 } 1877 if (kn == marker) { 1878 KQ_FLUX_WAKEUP(kq); 1879 if (count == maxevents) 1880 goto retry; 1881 goto done; 1882 } 1883 KASSERT(!kn_in_flux(kn), 1884 ("knote %p is unexpectedly in flux", kn)); 1885 1886 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1887 kn->kn_status &= ~KN_QUEUED; 1888 kn_enter_flux(kn); 1889 kq->kq_count--; 1890 KQ_UNLOCK(kq); 1891 /* 1892 * We don't need to lock the list since we've 1893 * marked it as in flux. 1894 */ 1895 knote_drop(kn, td); 1896 KQ_LOCK(kq); 1897 continue; 1898 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1899 kn->kn_status &= ~KN_QUEUED; 1900 kn_enter_flux(kn); 1901 kq->kq_count--; 1902 KQ_UNLOCK(kq); 1903 /* 1904 * We don't need to lock the list since we've 1905 * marked the knote as being in flux. 1906 */ 1907 *kevp = kn->kn_kevent; 1908 knote_drop(kn, td); 1909 KQ_LOCK(kq); 1910 kn = NULL; 1911 } else { 1912 kn->kn_status |= KN_SCAN; 1913 kn_enter_flux(kn); 1914 KQ_UNLOCK(kq); 1915 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1916 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1917 knl = kn_list_lock(kn); 1918 if (kn->kn_fop->f_event(kn, 0) == 0) { 1919 KQ_LOCK(kq); 1920 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1921 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1922 KN_SCAN); 1923 kn_leave_flux(kn); 1924 kq->kq_count--; 1925 kn_list_unlock(knl); 1926 influx = 1; 1927 continue; 1928 } 1929 touch = (!kn->kn_fop->f_isfd && 1930 kn->kn_fop->f_touch != NULL); 1931 if (touch) 1932 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1933 else 1934 *kevp = kn->kn_kevent; 1935 KQ_LOCK(kq); 1936 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1937 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1938 /* 1939 * Manually clear knotes who weren't 1940 * 'touch'ed. 1941 */ 1942 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1943 kn->kn_data = 0; 1944 kn->kn_fflags = 0; 1945 } 1946 if (kn->kn_flags & EV_DISPATCH) 1947 kn->kn_status |= KN_DISABLED; 1948 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1949 kq->kq_count--; 1950 } else 1951 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1952 1953 kn->kn_status &= ~KN_SCAN; 1954 kn_leave_flux(kn); 1955 kn_list_unlock(knl); 1956 influx = 1; 1957 } 1958 1959 /* we are returning a copy to the user */ 1960 kevp++; 1961 nkev++; 1962 count--; 1963 1964 if (nkev == KQ_NEVENTS) { 1965 influx = 0; 1966 KQ_UNLOCK_FLUX(kq); 1967 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1968 nkev = 0; 1969 kevp = keva; 1970 KQ_LOCK(kq); 1971 if (error) 1972 break; 1973 } 1974 } 1975 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1976 done: 1977 KQ_OWNED(kq); 1978 KQ_UNLOCK_FLUX(kq); 1979 knote_free(marker); 1980 done_nl: 1981 KQ_NOTOWNED(kq); 1982 if (nkev != 0) 1983 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1984 td->td_retval[0] = maxevents - count; 1985 return (error); 1986 } 1987 1988 /*ARGSUSED*/ 1989 static int 1990 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1991 struct ucred *active_cred, struct thread *td) 1992 { 1993 /* 1994 * Enabling sigio causes two major problems: 1995 * 1) infinite recursion: 1996 * Synopsys: kevent is being used to track signals and have FIOASYNC 1997 * set. On receipt of a signal this will cause a kqueue to recurse 1998 * into itself over and over. Sending the sigio causes the kqueue 1999 * to become ready, which in turn posts sigio again, forever. 2000 * Solution: this can be solved by setting a flag in the kqueue that 2001 * we have a SIGIO in progress. 2002 * 2) locking problems: 2003 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 2004 * us above the proc and pgrp locks. 2005 * Solution: Post a signal using an async mechanism, being sure to 2006 * record a generation count in the delivery so that we do not deliver 2007 * a signal to the wrong process. 2008 * 2009 * Note, these two mechanisms are somewhat mutually exclusive! 2010 */ 2011 #if 0 2012 struct kqueue *kq; 2013 2014 kq = fp->f_data; 2015 switch (cmd) { 2016 case FIOASYNC: 2017 if (*(int *)data) { 2018 kq->kq_state |= KQ_ASYNC; 2019 } else { 2020 kq->kq_state &= ~KQ_ASYNC; 2021 } 2022 return (0); 2023 2024 case FIOSETOWN: 2025 return (fsetown(*(int *)data, &kq->kq_sigio)); 2026 2027 case FIOGETOWN: 2028 *(int *)data = fgetown(&kq->kq_sigio); 2029 return (0); 2030 } 2031 #endif 2032 2033 return (ENOTTY); 2034 } 2035 2036 /*ARGSUSED*/ 2037 static int 2038 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 2039 struct thread *td) 2040 { 2041 struct kqueue *kq; 2042 int revents = 0; 2043 int error; 2044 2045 if ((error = kqueue_acquire(fp, &kq))) 2046 return POLLERR; 2047 2048 KQ_LOCK(kq); 2049 if (events & (POLLIN | POLLRDNORM)) { 2050 if (kq->kq_count) { 2051 revents |= events & (POLLIN | POLLRDNORM); 2052 } else { 2053 selrecord(td, &kq->kq_sel); 2054 if (SEL_WAITING(&kq->kq_sel)) 2055 kq->kq_state |= KQ_SEL; 2056 } 2057 } 2058 kqueue_release(kq, 1); 2059 KQ_UNLOCK(kq); 2060 return (revents); 2061 } 2062 2063 /*ARGSUSED*/ 2064 static int 2065 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 2066 struct thread *td) 2067 { 2068 2069 bzero((void *)st, sizeof *st); 2070 /* 2071 * We no longer return kq_count because the unlocked value is useless. 2072 * If you spent all this time getting the count, why not spend your 2073 * syscall better by calling kevent? 2074 * 2075 * XXX - This is needed for libc_r. 2076 */ 2077 st->st_mode = S_IFIFO; 2078 return (0); 2079 } 2080 2081 static void 2082 kqueue_drain(struct kqueue *kq, struct thread *td) 2083 { 2084 struct knote *kn; 2085 int i; 2086 2087 KQ_LOCK(kq); 2088 2089 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 2090 ("kqueue already closing")); 2091 kq->kq_state |= KQ_CLOSING; 2092 if (kq->kq_refcnt > 1) 2093 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 2094 2095 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 2096 2097 KASSERT(knlist_empty(&kq->kq_sel.si_note), 2098 ("kqueue's knlist not empty")); 2099 2100 for (i = 0; i < kq->kq_knlistsize; i++) { 2101 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 2102 if (kn_in_flux(kn)) { 2103 kq->kq_state |= KQ_FLUXWAIT; 2104 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 2105 continue; 2106 } 2107 kn_enter_flux(kn); 2108 KQ_UNLOCK(kq); 2109 knote_drop(kn, td); 2110 KQ_LOCK(kq); 2111 } 2112 } 2113 if (kq->kq_knhashmask != 0) { 2114 for (i = 0; i <= kq->kq_knhashmask; i++) { 2115 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 2116 if (kn_in_flux(kn)) { 2117 kq->kq_state |= KQ_FLUXWAIT; 2118 msleep(kq, &kq->kq_lock, PSOCK, 2119 "kqclo2", 0); 2120 continue; 2121 } 2122 kn_enter_flux(kn); 2123 KQ_UNLOCK(kq); 2124 knote_drop(kn, td); 2125 KQ_LOCK(kq); 2126 } 2127 } 2128 } 2129 2130 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 2131 kq->kq_state |= KQ_TASKDRAIN; 2132 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 2133 } 2134 2135 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2136 selwakeuppri(&kq->kq_sel, PSOCK); 2137 if (!SEL_WAITING(&kq->kq_sel)) 2138 kq->kq_state &= ~KQ_SEL; 2139 } 2140 2141 KQ_UNLOCK(kq); 2142 } 2143 2144 static void 2145 kqueue_destroy(struct kqueue *kq) 2146 { 2147 2148 KASSERT(kq->kq_fdp == NULL, 2149 ("kqueue still attached to a file descriptor")); 2150 seldrain(&kq->kq_sel); 2151 knlist_destroy(&kq->kq_sel.si_note); 2152 mtx_destroy(&kq->kq_lock); 2153 2154 if (kq->kq_knhash != NULL) 2155 free(kq->kq_knhash, M_KQUEUE); 2156 if (kq->kq_knlist != NULL) 2157 free(kq->kq_knlist, M_KQUEUE); 2158 2159 funsetown(&kq->kq_sigio); 2160 } 2161 2162 /*ARGSUSED*/ 2163 static int 2164 kqueue_close(struct file *fp, struct thread *td) 2165 { 2166 struct kqueue *kq = fp->f_data; 2167 struct filedesc *fdp; 2168 int error; 2169 int filedesc_unlock; 2170 2171 if ((error = kqueue_acquire(fp, &kq))) 2172 return error; 2173 kqueue_drain(kq, td); 2174 2175 /* 2176 * We could be called due to the knote_drop() doing fdrop(), 2177 * called from kqueue_register(). In this case the global 2178 * lock is owned, and filedesc sx is locked before, to not 2179 * take the sleepable lock after non-sleepable. 2180 */ 2181 fdp = kq->kq_fdp; 2182 kq->kq_fdp = NULL; 2183 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 2184 FILEDESC_XLOCK(fdp); 2185 filedesc_unlock = 1; 2186 } else 2187 filedesc_unlock = 0; 2188 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 2189 if (filedesc_unlock) 2190 FILEDESC_XUNLOCK(fdp); 2191 2192 kqueue_destroy(kq); 2193 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 2194 crfree(kq->kq_cred); 2195 free(kq, M_KQUEUE); 2196 fp->f_data = NULL; 2197 2198 return (0); 2199 } 2200 2201 static int 2202 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2203 { 2204 2205 kif->kf_type = KF_TYPE_KQUEUE; 2206 return (0); 2207 } 2208 2209 static void 2210 kqueue_wakeup(struct kqueue *kq) 2211 { 2212 KQ_OWNED(kq); 2213 2214 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2215 kq->kq_state &= ~KQ_SLEEP; 2216 wakeup(kq); 2217 } 2218 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2219 selwakeuppri(&kq->kq_sel, PSOCK); 2220 if (!SEL_WAITING(&kq->kq_sel)) 2221 kq->kq_state &= ~KQ_SEL; 2222 } 2223 if (!knlist_empty(&kq->kq_sel.si_note)) 2224 kqueue_schedtask(kq); 2225 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2226 pgsigio(&kq->kq_sigio, SIGIO, 0); 2227 } 2228 } 2229 2230 /* 2231 * Walk down a list of knotes, activating them if their event has triggered. 2232 * 2233 * There is a possibility to optimize in the case of one kq watching another. 2234 * Instead of scheduling a task to wake it up, you could pass enough state 2235 * down the chain to make up the parent kqueue. Make this code functional 2236 * first. 2237 */ 2238 void 2239 knote(struct knlist *list, long hint, int lockflags) 2240 { 2241 struct kqueue *kq; 2242 struct knote *kn, *tkn; 2243 int error; 2244 2245 if (list == NULL) 2246 return; 2247 2248 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2249 2250 if ((lockflags & KNF_LISTLOCKED) == 0) 2251 list->kl_lock(list->kl_lockarg); 2252 2253 /* 2254 * If we unlock the list lock (and enter influx), we can 2255 * eliminate the kqueue scheduling, but this will introduce 2256 * four lock/unlock's for each knote to test. Also, marker 2257 * would be needed to keep iteration position, since filters 2258 * or other threads could remove events. 2259 */ 2260 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2261 kq = kn->kn_kq; 2262 KQ_LOCK(kq); 2263 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2264 /* 2265 * Do not process the influx notes, except for 2266 * the influx coming from the kq unlock in the 2267 * kqueue_scan(). In the later case, we do 2268 * not interfere with the scan, since the code 2269 * fragment in kqueue_scan() locks the knlist, 2270 * and cannot proceed until we finished. 2271 */ 2272 KQ_UNLOCK(kq); 2273 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2274 kn_enter_flux(kn); 2275 KQ_UNLOCK(kq); 2276 error = kn->kn_fop->f_event(kn, hint); 2277 KQ_LOCK(kq); 2278 kn_leave_flux(kn); 2279 if (error) 2280 KNOTE_ACTIVATE(kn, 1); 2281 KQ_UNLOCK_FLUX(kq); 2282 } else { 2283 if (kn->kn_fop->f_event(kn, hint)) 2284 KNOTE_ACTIVATE(kn, 1); 2285 KQ_UNLOCK(kq); 2286 } 2287 } 2288 if ((lockflags & KNF_LISTLOCKED) == 0) 2289 list->kl_unlock(list->kl_lockarg); 2290 } 2291 2292 /* 2293 * add a knote to a knlist 2294 */ 2295 void 2296 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2297 { 2298 2299 KNL_ASSERT_LOCK(knl, islocked); 2300 KQ_NOTOWNED(kn->kn_kq); 2301 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2302 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2303 ("knote %p was not detached", kn)); 2304 if (!islocked) 2305 knl->kl_lock(knl->kl_lockarg); 2306 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2307 if (!islocked) 2308 knl->kl_unlock(knl->kl_lockarg); 2309 KQ_LOCK(kn->kn_kq); 2310 kn->kn_knlist = knl; 2311 kn->kn_status &= ~KN_DETACHED; 2312 KQ_UNLOCK(kn->kn_kq); 2313 } 2314 2315 static void 2316 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2317 int kqislocked) 2318 { 2319 2320 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2321 KNL_ASSERT_LOCK(knl, knlislocked); 2322 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2323 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2324 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2325 ("knote %p was already detached", kn)); 2326 if (!knlislocked) 2327 knl->kl_lock(knl->kl_lockarg); 2328 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2329 kn->kn_knlist = NULL; 2330 if (!knlislocked) 2331 kn_list_unlock(knl); 2332 if (!kqislocked) 2333 KQ_LOCK(kn->kn_kq); 2334 kn->kn_status |= KN_DETACHED; 2335 if (!kqislocked) 2336 KQ_UNLOCK(kn->kn_kq); 2337 } 2338 2339 /* 2340 * remove knote from the specified knlist 2341 */ 2342 void 2343 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2344 { 2345 2346 knlist_remove_kq(knl, kn, islocked, 0); 2347 } 2348 2349 int 2350 knlist_empty(struct knlist *knl) 2351 { 2352 2353 KNL_ASSERT_LOCKED(knl); 2354 return (SLIST_EMPTY(&knl->kl_list)); 2355 } 2356 2357 static struct mtx knlist_lock; 2358 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2359 MTX_DEF); 2360 static void knlist_mtx_lock(void *arg); 2361 static void knlist_mtx_unlock(void *arg); 2362 2363 static void 2364 knlist_mtx_lock(void *arg) 2365 { 2366 2367 mtx_lock((struct mtx *)arg); 2368 } 2369 2370 static void 2371 knlist_mtx_unlock(void *arg) 2372 { 2373 2374 mtx_unlock((struct mtx *)arg); 2375 } 2376 2377 static void 2378 knlist_mtx_assert_lock(void *arg, int what) 2379 { 2380 2381 if (what == LA_LOCKED) 2382 mtx_assert((struct mtx *)arg, MA_OWNED); 2383 else 2384 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2385 } 2386 2387 static void 2388 knlist_rw_rlock(void *arg) 2389 { 2390 2391 rw_rlock((struct rwlock *)arg); 2392 } 2393 2394 static void 2395 knlist_rw_runlock(void *arg) 2396 { 2397 2398 rw_runlock((struct rwlock *)arg); 2399 } 2400 2401 static void 2402 knlist_rw_assert_lock(void *arg, int what) 2403 { 2404 2405 if (what == LA_LOCKED) 2406 rw_assert((struct rwlock *)arg, RA_LOCKED); 2407 else 2408 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2409 } 2410 2411 void 2412 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2413 void (*kl_unlock)(void *), 2414 void (*kl_assert_lock)(void *, int)) 2415 { 2416 2417 if (lock == NULL) 2418 knl->kl_lockarg = &knlist_lock; 2419 else 2420 knl->kl_lockarg = lock; 2421 2422 if (kl_lock == NULL) 2423 knl->kl_lock = knlist_mtx_lock; 2424 else 2425 knl->kl_lock = kl_lock; 2426 if (kl_unlock == NULL) 2427 knl->kl_unlock = knlist_mtx_unlock; 2428 else 2429 knl->kl_unlock = kl_unlock; 2430 if (kl_assert_lock == NULL) 2431 knl->kl_assert_lock = knlist_mtx_assert_lock; 2432 else 2433 knl->kl_assert_lock = kl_assert_lock; 2434 2435 knl->kl_autodestroy = 0; 2436 SLIST_INIT(&knl->kl_list); 2437 } 2438 2439 void 2440 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2441 { 2442 2443 knlist_init(knl, lock, NULL, NULL, NULL); 2444 } 2445 2446 struct knlist * 2447 knlist_alloc(struct mtx *lock) 2448 { 2449 struct knlist *knl; 2450 2451 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2452 knlist_init_mtx(knl, lock); 2453 return (knl); 2454 } 2455 2456 void 2457 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2458 { 2459 2460 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2461 knlist_rw_assert_lock); 2462 } 2463 2464 void 2465 knlist_destroy(struct knlist *knl) 2466 { 2467 2468 KASSERT(KNLIST_EMPTY(knl), 2469 ("destroying knlist %p with knotes on it", knl)); 2470 } 2471 2472 void 2473 knlist_detach(struct knlist *knl) 2474 { 2475 2476 KNL_ASSERT_LOCKED(knl); 2477 knl->kl_autodestroy = 1; 2478 if (knlist_empty(knl)) { 2479 knlist_destroy(knl); 2480 free(knl, M_KQUEUE); 2481 } 2482 } 2483 2484 /* 2485 * Even if we are locked, we may need to drop the lock to allow any influx 2486 * knotes time to "settle". 2487 */ 2488 void 2489 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2490 { 2491 struct knote *kn, *kn2; 2492 struct kqueue *kq; 2493 2494 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2495 if (islocked) 2496 KNL_ASSERT_LOCKED(knl); 2497 else { 2498 KNL_ASSERT_UNLOCKED(knl); 2499 again: /* need to reacquire lock since we have dropped it */ 2500 knl->kl_lock(knl->kl_lockarg); 2501 } 2502 2503 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2504 kq = kn->kn_kq; 2505 KQ_LOCK(kq); 2506 if (kn_in_flux(kn)) { 2507 KQ_UNLOCK(kq); 2508 continue; 2509 } 2510 knlist_remove_kq(knl, kn, 1, 1); 2511 if (killkn) { 2512 kn_enter_flux(kn); 2513 KQ_UNLOCK(kq); 2514 knote_drop_detached(kn, td); 2515 } else { 2516 /* Make sure cleared knotes disappear soon */ 2517 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2518 KQ_UNLOCK(kq); 2519 } 2520 kq = NULL; 2521 } 2522 2523 if (!SLIST_EMPTY(&knl->kl_list)) { 2524 /* there are still in flux knotes remaining */ 2525 kn = SLIST_FIRST(&knl->kl_list); 2526 kq = kn->kn_kq; 2527 KQ_LOCK(kq); 2528 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2529 knl->kl_unlock(knl->kl_lockarg); 2530 kq->kq_state |= KQ_FLUXWAIT; 2531 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2532 kq = NULL; 2533 goto again; 2534 } 2535 2536 if (islocked) 2537 KNL_ASSERT_LOCKED(knl); 2538 else { 2539 knl->kl_unlock(knl->kl_lockarg); 2540 KNL_ASSERT_UNLOCKED(knl); 2541 } 2542 } 2543 2544 /* 2545 * Remove all knotes referencing a specified fd must be called with FILEDESC 2546 * lock. This prevents a race where a new fd comes along and occupies the 2547 * entry and we attach a knote to the fd. 2548 */ 2549 void 2550 knote_fdclose(struct thread *td, int fd) 2551 { 2552 struct filedesc *fdp = td->td_proc->p_fd; 2553 struct kqueue *kq; 2554 struct knote *kn; 2555 int influx; 2556 2557 FILEDESC_XLOCK_ASSERT(fdp); 2558 2559 /* 2560 * We shouldn't have to worry about new kevents appearing on fd 2561 * since filedesc is locked. 2562 */ 2563 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2564 KQ_LOCK(kq); 2565 2566 again: 2567 influx = 0; 2568 while (kq->kq_knlistsize > fd && 2569 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2570 if (kn_in_flux(kn)) { 2571 /* someone else might be waiting on our knote */ 2572 if (influx) 2573 wakeup(kq); 2574 kq->kq_state |= KQ_FLUXWAIT; 2575 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2576 goto again; 2577 } 2578 kn_enter_flux(kn); 2579 KQ_UNLOCK(kq); 2580 influx = 1; 2581 knote_drop(kn, td); 2582 KQ_LOCK(kq); 2583 } 2584 KQ_UNLOCK_FLUX(kq); 2585 } 2586 } 2587 2588 static int 2589 knote_attach(struct knote *kn, struct kqueue *kq) 2590 { 2591 struct klist *list; 2592 2593 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2594 KQ_OWNED(kq); 2595 2596 if ((kq->kq_state & KQ_CLOSING) != 0) 2597 return (EBADF); 2598 if (kn->kn_fop->f_isfd) { 2599 if (kn->kn_id >= kq->kq_knlistsize) 2600 return (ENOMEM); 2601 list = &kq->kq_knlist[kn->kn_id]; 2602 } else { 2603 if (kq->kq_knhash == NULL) 2604 return (ENOMEM); 2605 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2606 } 2607 SLIST_INSERT_HEAD(list, kn, kn_link); 2608 return (0); 2609 } 2610 2611 static void 2612 knote_drop(struct knote *kn, struct thread *td) 2613 { 2614 2615 if ((kn->kn_status & KN_DETACHED) == 0) 2616 kn->kn_fop->f_detach(kn); 2617 knote_drop_detached(kn, td); 2618 } 2619 2620 static void 2621 knote_drop_detached(struct knote *kn, struct thread *td) 2622 { 2623 struct kqueue *kq; 2624 struct klist *list; 2625 2626 kq = kn->kn_kq; 2627 2628 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2629 ("knote %p still attached", kn)); 2630 KQ_NOTOWNED(kq); 2631 2632 KQ_LOCK(kq); 2633 KASSERT(kn->kn_influx == 1, 2634 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2635 2636 if (kn->kn_fop->f_isfd) 2637 list = &kq->kq_knlist[kn->kn_id]; 2638 else 2639 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2640 2641 if (!SLIST_EMPTY(list)) 2642 SLIST_REMOVE(list, kn, knote, kn_link); 2643 if (kn->kn_status & KN_QUEUED) 2644 knote_dequeue(kn); 2645 KQ_UNLOCK_FLUX(kq); 2646 2647 if (kn->kn_fop->f_isfd) { 2648 fdrop(kn->kn_fp, td); 2649 kn->kn_fp = NULL; 2650 } 2651 kqueue_fo_release(kn->kn_kevent.filter); 2652 kn->kn_fop = NULL; 2653 knote_free(kn); 2654 } 2655 2656 static void 2657 knote_enqueue(struct knote *kn) 2658 { 2659 struct kqueue *kq = kn->kn_kq; 2660 2661 KQ_OWNED(kn->kn_kq); 2662 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2663 2664 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2665 kn->kn_status |= KN_QUEUED; 2666 kq->kq_count++; 2667 kqueue_wakeup(kq); 2668 } 2669 2670 static void 2671 knote_dequeue(struct knote *kn) 2672 { 2673 struct kqueue *kq = kn->kn_kq; 2674 2675 KQ_OWNED(kn->kn_kq); 2676 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2677 2678 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2679 kn->kn_status &= ~KN_QUEUED; 2680 kq->kq_count--; 2681 } 2682 2683 static void 2684 knote_init(void) 2685 { 2686 2687 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2688 NULL, NULL, UMA_ALIGN_PTR, 0); 2689 } 2690 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2691 2692 static struct knote * 2693 knote_alloc(int mflag) 2694 { 2695 2696 return (uma_zalloc(knote_zone, mflag | M_ZERO)); 2697 } 2698 2699 static void 2700 knote_free(struct knote *kn) 2701 { 2702 2703 uma_zfree(knote_zone, kn); 2704 } 2705 2706 /* 2707 * Register the kev w/ the kq specified by fd. 2708 */ 2709 int 2710 kqfd_register(int fd, struct kevent *kev, struct thread *td, int mflag) 2711 { 2712 struct kqueue *kq; 2713 struct file *fp; 2714 cap_rights_t rights; 2715 int error; 2716 2717 error = fget(td, fd, cap_rights_init_one(&rights, CAP_KQUEUE_CHANGE), 2718 &fp); 2719 if (error != 0) 2720 return (error); 2721 if ((error = kqueue_acquire(fp, &kq)) != 0) 2722 goto noacquire; 2723 2724 error = kqueue_register(kq, kev, td, mflag); 2725 kqueue_release(kq, 0); 2726 2727 noacquire: 2728 fdrop(fp, td); 2729 return (error); 2730 }
Cache object: 2360872c2551ed42bc5f0a4233a4096a
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