Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]
FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
Version:
- FREEBSD - FREEBSD-13-STABLE - FREEBSD-13-0 - FREEBSD-12-STABLE - FREEBSD-12-0 - FREEBSD-11-STABLE - FREEBSD-11-0 - FREEBSD-10-STABLE - FREEBSD-10-0 - FREEBSD-9-STABLE - FREEBSD-9-0 - FREEBSD-8-STABLE - FREEBSD-8-0 - FREEBSD-7-STABLE - FREEBSD-7-0 - FREEBSD-6-STABLE - FREEBSD-6-0 - FREEBSD-5-STABLE - FREEBSD-5-0 - FREEBSD-4-STABLE - FREEBSD-3-STABLE - FREEBSD22 - l41 - OPENBSD - linux-2.6 - MK84 - PLAN9 - xnu-8792
SearchContext: - none - 3 - 10
SearchContext: - none - 3 - 10
1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 4 * Copyright (c) 2009 Apple, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD: releng/10.3/sys/kern/kern_event.c 293545 2016-01-09 16:39:15Z dchagin $"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/capsicum.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/rwlock.h> 41 #include <sys/proc.h> 42 #include <sys/malloc.h> 43 #include <sys/unistd.h> 44 #include <sys/file.h> 45 #include <sys/filedesc.h> 46 #include <sys/filio.h> 47 #include <sys/fcntl.h> 48 #include <sys/kthread.h> 49 #include <sys/selinfo.h> 50 #include <sys/stdatomic.h> 51 #include <sys/queue.h> 52 #include <sys/event.h> 53 #include <sys/eventvar.h> 54 #include <sys/poll.h> 55 #include <sys/protosw.h> 56 #include <sys/sigio.h> 57 #include <sys/signalvar.h> 58 #include <sys/socket.h> 59 #include <sys/socketvar.h> 60 #include <sys/stat.h> 61 #include <sys/sysctl.h> 62 #include <sys/sysproto.h> 63 #include <sys/syscallsubr.h> 64 #include <sys/taskqueue.h> 65 #include <sys/uio.h> 66 #ifdef KTRACE 67 #include <sys/ktrace.h> 68 #endif 69 70 #include <vm/uma.h> 71 72 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 73 74 /* 75 * This lock is used if multiple kq locks are required. This possibly 76 * should be made into a per proc lock. 77 */ 78 static struct mtx kq_global; 79 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 80 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 81 if (!haslck) \ 82 mtx_lock(lck); \ 83 haslck = 1; \ 84 } while (0) 85 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 86 if (haslck) \ 87 mtx_unlock(lck); \ 88 haslck = 0; \ 89 } while (0) 90 91 TASKQUEUE_DEFINE_THREAD(kqueue); 92 93 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 94 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 95 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 96 struct thread *td, int waitok); 97 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 98 static void kqueue_release(struct kqueue *kq, int locked); 99 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 100 uintptr_t ident, int waitok); 101 static void kqueue_task(void *arg, int pending); 102 static int kqueue_scan(struct kqueue *kq, int maxevents, 103 struct kevent_copyops *k_ops, 104 const struct timespec *timeout, 105 struct kevent *keva, struct thread *td); 106 static void kqueue_wakeup(struct kqueue *kq); 107 static struct filterops *kqueue_fo_find(int filt); 108 static void kqueue_fo_release(int filt); 109 110 static fo_rdwr_t kqueue_read; 111 static fo_rdwr_t kqueue_write; 112 static fo_truncate_t kqueue_truncate; 113 static fo_ioctl_t kqueue_ioctl; 114 static fo_poll_t kqueue_poll; 115 static fo_kqfilter_t kqueue_kqfilter; 116 static fo_stat_t kqueue_stat; 117 static fo_close_t kqueue_close; 118 119 static struct fileops kqueueops = { 120 .fo_read = kqueue_read, 121 .fo_write = kqueue_write, 122 .fo_truncate = kqueue_truncate, 123 .fo_ioctl = kqueue_ioctl, 124 .fo_poll = kqueue_poll, 125 .fo_kqfilter = kqueue_kqfilter, 126 .fo_stat = kqueue_stat, 127 .fo_close = kqueue_close, 128 .fo_chmod = invfo_chmod, 129 .fo_chown = invfo_chown, 130 .fo_sendfile = invfo_sendfile, 131 }; 132 133 static int knote_attach(struct knote *kn, struct kqueue *kq); 134 static void knote_drop(struct knote *kn, struct thread *td); 135 static void knote_enqueue(struct knote *kn); 136 static void knote_dequeue(struct knote *kn); 137 static void knote_init(void); 138 static struct knote *knote_alloc(int waitok); 139 static void knote_free(struct knote *kn); 140 141 static void filt_kqdetach(struct knote *kn); 142 static int filt_kqueue(struct knote *kn, long hint); 143 static int filt_procattach(struct knote *kn); 144 static void filt_procdetach(struct knote *kn); 145 static int filt_proc(struct knote *kn, long hint); 146 static int filt_fileattach(struct knote *kn); 147 static void filt_timerexpire(void *knx); 148 static int filt_timerattach(struct knote *kn); 149 static void filt_timerdetach(struct knote *kn); 150 static int filt_timer(struct knote *kn, long hint); 151 static int filt_userattach(struct knote *kn); 152 static void filt_userdetach(struct knote *kn); 153 static int filt_user(struct knote *kn, long hint); 154 static void filt_usertouch(struct knote *kn, struct kevent *kev, 155 u_long type); 156 157 static struct filterops file_filtops = { 158 .f_isfd = 1, 159 .f_attach = filt_fileattach, 160 }; 161 static struct filterops kqread_filtops = { 162 .f_isfd = 1, 163 .f_detach = filt_kqdetach, 164 .f_event = filt_kqueue, 165 }; 166 /* XXX - move to kern_proc.c? */ 167 static struct filterops proc_filtops = { 168 .f_isfd = 0, 169 .f_attach = filt_procattach, 170 .f_detach = filt_procdetach, 171 .f_event = filt_proc, 172 }; 173 static struct filterops timer_filtops = { 174 .f_isfd = 0, 175 .f_attach = filt_timerattach, 176 .f_detach = filt_timerdetach, 177 .f_event = filt_timer, 178 }; 179 static struct filterops user_filtops = { 180 .f_attach = filt_userattach, 181 .f_detach = filt_userdetach, 182 .f_event = filt_user, 183 .f_touch = filt_usertouch, 184 }; 185 186 static uma_zone_t knote_zone; 187 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 188 static unsigned int kq_calloutmax = 4 * 1024; 189 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 190 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 191 192 /* XXX - ensure not KN_INFLUX?? */ 193 #define KNOTE_ACTIVATE(kn, islock) do { \ 194 if ((islock)) \ 195 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 196 else \ 197 KQ_LOCK((kn)->kn_kq); \ 198 (kn)->kn_status |= KN_ACTIVE; \ 199 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 200 knote_enqueue((kn)); \ 201 if (!(islock)) \ 202 KQ_UNLOCK((kn)->kn_kq); \ 203 } while(0) 204 #define KQ_LOCK(kq) do { \ 205 mtx_lock(&(kq)->kq_lock); \ 206 } while (0) 207 #define KQ_FLUX_WAKEUP(kq) do { \ 208 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 209 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 210 wakeup((kq)); \ 211 } \ 212 } while (0) 213 #define KQ_UNLOCK_FLUX(kq) do { \ 214 KQ_FLUX_WAKEUP(kq); \ 215 mtx_unlock(&(kq)->kq_lock); \ 216 } while (0) 217 #define KQ_UNLOCK(kq) do { \ 218 mtx_unlock(&(kq)->kq_lock); \ 219 } while (0) 220 #define KQ_OWNED(kq) do { \ 221 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 222 } while (0) 223 #define KQ_NOTOWNED(kq) do { \ 224 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 225 } while (0) 226 #define KN_LIST_LOCK(kn) do { \ 227 if (kn->kn_knlist != NULL) \ 228 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 229 } while (0) 230 #define KN_LIST_UNLOCK(kn) do { \ 231 if (kn->kn_knlist != NULL) \ 232 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 233 } while (0) 234 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 235 if (islocked) \ 236 KNL_ASSERT_LOCKED(knl); \ 237 else \ 238 KNL_ASSERT_UNLOCKED(knl); \ 239 } while (0) 240 #ifdef INVARIANTS 241 #define KNL_ASSERT_LOCKED(knl) do { \ 242 knl->kl_assert_locked((knl)->kl_lockarg); \ 243 } while (0) 244 #define KNL_ASSERT_UNLOCKED(knl) do { \ 245 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 246 } while (0) 247 #else /* !INVARIANTS */ 248 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 249 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 250 #endif /* INVARIANTS */ 251 252 #define KN_HASHSIZE 64 /* XXX should be tunable */ 253 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 254 255 static int 256 filt_nullattach(struct knote *kn) 257 { 258 259 return (ENXIO); 260 }; 261 262 struct filterops null_filtops = { 263 .f_isfd = 0, 264 .f_attach = filt_nullattach, 265 }; 266 267 /* XXX - make SYSINIT to add these, and move into respective modules. */ 268 extern struct filterops sig_filtops; 269 extern struct filterops fs_filtops; 270 271 /* 272 * Table for for all system-defined filters. 273 */ 274 static struct mtx filterops_lock; 275 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 276 MTX_DEF); 277 static struct { 278 struct filterops *for_fop; 279 int for_refcnt; 280 } sysfilt_ops[EVFILT_SYSCOUNT] = { 281 { &file_filtops }, /* EVFILT_READ */ 282 { &file_filtops }, /* EVFILT_WRITE */ 283 { &null_filtops }, /* EVFILT_AIO */ 284 { &file_filtops }, /* EVFILT_VNODE */ 285 { &proc_filtops }, /* EVFILT_PROC */ 286 { &sig_filtops }, /* EVFILT_SIGNAL */ 287 { &timer_filtops }, /* EVFILT_TIMER */ 288 { &null_filtops }, /* former EVFILT_NETDEV */ 289 { &fs_filtops }, /* EVFILT_FS */ 290 { &null_filtops }, /* EVFILT_LIO */ 291 { &user_filtops }, /* EVFILT_USER */ 292 }; 293 294 /* 295 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 296 * method. 297 */ 298 static int 299 filt_fileattach(struct knote *kn) 300 { 301 302 return (fo_kqfilter(kn->kn_fp, kn)); 303 } 304 305 /*ARGSUSED*/ 306 static int 307 kqueue_kqfilter(struct file *fp, struct knote *kn) 308 { 309 struct kqueue *kq = kn->kn_fp->f_data; 310 311 if (kn->kn_filter != EVFILT_READ) 312 return (EINVAL); 313 314 kn->kn_status |= KN_KQUEUE; 315 kn->kn_fop = &kqread_filtops; 316 knlist_add(&kq->kq_sel.si_note, kn, 0); 317 318 return (0); 319 } 320 321 static void 322 filt_kqdetach(struct knote *kn) 323 { 324 struct kqueue *kq = kn->kn_fp->f_data; 325 326 knlist_remove(&kq->kq_sel.si_note, kn, 0); 327 } 328 329 /*ARGSUSED*/ 330 static int 331 filt_kqueue(struct knote *kn, long hint) 332 { 333 struct kqueue *kq = kn->kn_fp->f_data; 334 335 kn->kn_data = kq->kq_count; 336 return (kn->kn_data > 0); 337 } 338 339 /* XXX - move to kern_proc.c? */ 340 static int 341 filt_procattach(struct knote *kn) 342 { 343 struct proc *p; 344 int immediate; 345 int error; 346 347 immediate = 0; 348 p = pfind(kn->kn_id); 349 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 350 p = zpfind(kn->kn_id); 351 immediate = 1; 352 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 353 immediate = 1; 354 } 355 356 if (p == NULL) 357 return (ESRCH); 358 if ((error = p_cansee(curthread, p))) { 359 PROC_UNLOCK(p); 360 return (error); 361 } 362 363 kn->kn_ptr.p_proc = p; 364 kn->kn_flags |= EV_CLEAR; /* automatically set */ 365 366 /* 367 * internal flag indicating registration done by kernel 368 */ 369 if (kn->kn_flags & EV_FLAG1) { 370 kn->kn_data = kn->kn_sdata; /* ppid */ 371 kn->kn_fflags = NOTE_CHILD; 372 kn->kn_flags &= ~EV_FLAG1; 373 } 374 375 if (immediate == 0) 376 knlist_add(&p->p_klist, kn, 1); 377 378 /* 379 * Immediately activate any exit notes if the target process is a 380 * zombie. This is necessary to handle the case where the target 381 * process, e.g. a child, dies before the kevent is registered. 382 */ 383 if (immediate && filt_proc(kn, NOTE_EXIT)) 384 KNOTE_ACTIVATE(kn, 0); 385 386 PROC_UNLOCK(p); 387 388 return (0); 389 } 390 391 /* 392 * The knote may be attached to a different process, which may exit, 393 * leaving nothing for the knote to be attached to. So when the process 394 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 395 * it will be deleted when read out. However, as part of the knote deletion, 396 * this routine is called, so a check is needed to avoid actually performing 397 * a detach, because the original process does not exist any more. 398 */ 399 /* XXX - move to kern_proc.c? */ 400 static void 401 filt_procdetach(struct knote *kn) 402 { 403 struct proc *p; 404 405 p = kn->kn_ptr.p_proc; 406 knlist_remove(&p->p_klist, kn, 0); 407 kn->kn_ptr.p_proc = NULL; 408 } 409 410 /* XXX - move to kern_proc.c? */ 411 static int 412 filt_proc(struct knote *kn, long hint) 413 { 414 struct proc *p = kn->kn_ptr.p_proc; 415 u_int event; 416 417 /* 418 * mask off extra data 419 */ 420 event = (u_int)hint & NOTE_PCTRLMASK; 421 422 /* 423 * if the user is interested in this event, record it. 424 */ 425 if (kn->kn_sfflags & event) 426 kn->kn_fflags |= event; 427 428 /* 429 * process is gone, so flag the event as finished. 430 */ 431 if (event == NOTE_EXIT) { 432 if (!(kn->kn_status & KN_DETACHED)) 433 knlist_remove_inevent(&p->p_klist, kn); 434 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 435 kn->kn_ptr.p_proc = NULL; 436 if (kn->kn_fflags & NOTE_EXIT) 437 kn->kn_data = p->p_xstat; 438 if (kn->kn_fflags == 0) 439 kn->kn_flags |= EV_DROP; 440 return (1); 441 } 442 443 return (kn->kn_fflags != 0); 444 } 445 446 /* 447 * Called when the process forked. It mostly does the same as the 448 * knote(), activating all knotes registered to be activated when the 449 * process forked. Additionally, for each knote attached to the 450 * parent, check whether user wants to track the new process. If so 451 * attach a new knote to it, and immediately report an event with the 452 * child's pid. 453 */ 454 void 455 knote_fork(struct knlist *list, int pid) 456 { 457 struct kqueue *kq; 458 struct knote *kn; 459 struct kevent kev; 460 int error; 461 462 if (list == NULL) 463 return; 464 list->kl_lock(list->kl_lockarg); 465 466 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 467 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 468 continue; 469 kq = kn->kn_kq; 470 KQ_LOCK(kq); 471 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 472 KQ_UNLOCK(kq); 473 continue; 474 } 475 476 /* 477 * The same as knote(), activate the event. 478 */ 479 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 480 kn->kn_status |= KN_HASKQLOCK; 481 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 482 KNOTE_ACTIVATE(kn, 1); 483 kn->kn_status &= ~KN_HASKQLOCK; 484 KQ_UNLOCK(kq); 485 continue; 486 } 487 488 /* 489 * The NOTE_TRACK case. In addition to the activation 490 * of the event, we need to register new event to 491 * track the child. Drop the locks in preparation for 492 * the call to kqueue_register(). 493 */ 494 kn->kn_status |= KN_INFLUX; 495 KQ_UNLOCK(kq); 496 list->kl_unlock(list->kl_lockarg); 497 498 /* 499 * Activate existing knote and register a knote with 500 * new process. 501 */ 502 kev.ident = pid; 503 kev.filter = kn->kn_filter; 504 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 505 kev.fflags = kn->kn_sfflags; 506 kev.data = kn->kn_id; /* parent */ 507 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 508 error = kqueue_register(kq, &kev, NULL, 0); 509 if (error) 510 kn->kn_fflags |= NOTE_TRACKERR; 511 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 512 KNOTE_ACTIVATE(kn, 0); 513 KQ_LOCK(kq); 514 kn->kn_status &= ~KN_INFLUX; 515 KQ_UNLOCK_FLUX(kq); 516 list->kl_lock(list->kl_lockarg); 517 } 518 list->kl_unlock(list->kl_lockarg); 519 } 520 521 /* 522 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 523 * interval timer support code. 524 */ 525 526 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \ 527 NOTE_NSECONDS) 528 529 static __inline sbintime_t 530 timer2sbintime(intptr_t data, int flags) 531 { 532 sbintime_t modifier; 533 534 switch (flags & NOTE_TIMER_PRECMASK) { 535 case NOTE_SECONDS: 536 modifier = SBT_1S; 537 break; 538 case NOTE_MSECONDS: /* FALLTHROUGH */ 539 case 0: 540 modifier = SBT_1MS; 541 break; 542 case NOTE_USECONDS: 543 modifier = SBT_1US; 544 break; 545 case NOTE_NSECONDS: 546 modifier = SBT_1NS; 547 break; 548 default: 549 return (-1); 550 } 551 552 #ifdef __LP64__ 553 if (data > SBT_MAX / modifier) 554 return (SBT_MAX); 555 #endif 556 return (modifier * data); 557 } 558 559 static void 560 filt_timerexpire(void *knx) 561 { 562 struct callout *calloutp; 563 struct knote *kn; 564 565 kn = knx; 566 kn->kn_data++; 567 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 568 569 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 570 calloutp = (struct callout *)kn->kn_hook; 571 *kn->kn_ptr.p_nexttime += timer2sbintime(kn->kn_sdata, 572 kn->kn_sfflags); 573 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 574 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 575 } 576 } 577 578 /* 579 * data contains amount of time to sleep 580 */ 581 static int 582 filt_timerattach(struct knote *kn) 583 { 584 struct callout *calloutp; 585 sbintime_t to; 586 unsigned int ncallouts; 587 588 if ((intptr_t)kn->kn_sdata < 0) 589 return (EINVAL); 590 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 591 kn->kn_sdata = 1; 592 /* Only precision unit are supported in flags so far */ 593 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) 594 return (EINVAL); 595 596 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 597 if (to < 0) 598 return (EINVAL); 599 600 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 601 do { 602 if (ncallouts >= kq_calloutmax) 603 return (ENOMEM); 604 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 605 &ncallouts, ncallouts + 1, memory_order_relaxed, 606 memory_order_relaxed)); 607 608 kn->kn_flags |= EV_CLEAR; /* automatically set */ 609 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 610 kn->kn_ptr.p_nexttime = malloc(sizeof(sbintime_t), M_KQUEUE, M_WAITOK); 611 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 612 callout_init(calloutp, CALLOUT_MPSAFE); 613 kn->kn_hook = calloutp; 614 *kn->kn_ptr.p_nexttime = to + sbinuptime(); 615 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 616 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 617 618 return (0); 619 } 620 621 static void 622 filt_timerdetach(struct knote *kn) 623 { 624 struct callout *calloutp; 625 unsigned int old; 626 627 calloutp = (struct callout *)kn->kn_hook; 628 callout_drain(calloutp); 629 free(calloutp, M_KQUEUE); 630 free(kn->kn_ptr.p_nexttime, M_KQUEUE); 631 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 632 KASSERT(old > 0, ("Number of callouts cannot become negative")); 633 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 634 } 635 636 static int 637 filt_timer(struct knote *kn, long hint) 638 { 639 640 return (kn->kn_data != 0); 641 } 642 643 static int 644 filt_userattach(struct knote *kn) 645 { 646 647 /* 648 * EVFILT_USER knotes are not attached to anything in the kernel. 649 */ 650 kn->kn_hook = NULL; 651 if (kn->kn_fflags & NOTE_TRIGGER) 652 kn->kn_hookid = 1; 653 else 654 kn->kn_hookid = 0; 655 return (0); 656 } 657 658 static void 659 filt_userdetach(__unused struct knote *kn) 660 { 661 662 /* 663 * EVFILT_USER knotes are not attached to anything in the kernel. 664 */ 665 } 666 667 static int 668 filt_user(struct knote *kn, __unused long hint) 669 { 670 671 return (kn->kn_hookid); 672 } 673 674 static void 675 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 676 { 677 u_int ffctrl; 678 679 switch (type) { 680 case EVENT_REGISTER: 681 if (kev->fflags & NOTE_TRIGGER) 682 kn->kn_hookid = 1; 683 684 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 685 kev->fflags &= NOTE_FFLAGSMASK; 686 switch (ffctrl) { 687 case NOTE_FFNOP: 688 break; 689 690 case NOTE_FFAND: 691 kn->kn_sfflags &= kev->fflags; 692 break; 693 694 case NOTE_FFOR: 695 kn->kn_sfflags |= kev->fflags; 696 break; 697 698 case NOTE_FFCOPY: 699 kn->kn_sfflags = kev->fflags; 700 break; 701 702 default: 703 /* XXX Return error? */ 704 break; 705 } 706 kn->kn_sdata = kev->data; 707 if (kev->flags & EV_CLEAR) { 708 kn->kn_hookid = 0; 709 kn->kn_data = 0; 710 kn->kn_fflags = 0; 711 } 712 break; 713 714 case EVENT_PROCESS: 715 *kev = kn->kn_kevent; 716 kev->fflags = kn->kn_sfflags; 717 kev->data = kn->kn_sdata; 718 if (kn->kn_flags & EV_CLEAR) { 719 kn->kn_hookid = 0; 720 kn->kn_data = 0; 721 kn->kn_fflags = 0; 722 } 723 break; 724 725 default: 726 panic("filt_usertouch() - invalid type (%ld)", type); 727 break; 728 } 729 } 730 731 int 732 sys_kqueue(struct thread *td, struct kqueue_args *uap) 733 { 734 735 return (kern_kqueue(td, 0)); 736 } 737 738 int 739 kern_kqueue(struct thread *td, int flags) 740 { 741 struct filedesc *fdp; 742 struct kqueue *kq; 743 struct file *fp; 744 int fd, error; 745 746 fdp = td->td_proc->p_fd; 747 error = falloc(td, &fp, &fd, flags); 748 if (error) 749 goto done2; 750 751 /* An extra reference on `fp' has been held for us by falloc(). */ 752 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 753 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 754 TAILQ_INIT(&kq->kq_head); 755 kq->kq_fdp = fdp; 756 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 757 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 758 759 FILEDESC_XLOCK(fdp); 760 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 761 FILEDESC_XUNLOCK(fdp); 762 763 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 764 fdrop(fp, td); 765 766 td->td_retval[0] = fd; 767 done2: 768 return (error); 769 } 770 771 #ifndef _SYS_SYSPROTO_H_ 772 struct kevent_args { 773 int fd; 774 const struct kevent *changelist; 775 int nchanges; 776 struct kevent *eventlist; 777 int nevents; 778 const struct timespec *timeout; 779 }; 780 #endif 781 int 782 sys_kevent(struct thread *td, struct kevent_args *uap) 783 { 784 struct timespec ts, *tsp; 785 struct kevent_copyops k_ops = { uap, 786 kevent_copyout, 787 kevent_copyin}; 788 int error; 789 #ifdef KTRACE 790 struct uio ktruio; 791 struct iovec ktriov; 792 struct uio *ktruioin = NULL; 793 struct uio *ktruioout = NULL; 794 #endif 795 796 if (uap->timeout != NULL) { 797 error = copyin(uap->timeout, &ts, sizeof(ts)); 798 if (error) 799 return (error); 800 tsp = &ts; 801 } else 802 tsp = NULL; 803 804 #ifdef KTRACE 805 if (KTRPOINT(td, KTR_GENIO)) { 806 ktriov.iov_base = uap->changelist; 807 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 808 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 809 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 810 .uio_td = td }; 811 ktruioin = cloneuio(&ktruio); 812 ktriov.iov_base = uap->eventlist; 813 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 814 ktruioout = cloneuio(&ktruio); 815 } 816 #endif 817 818 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 819 &k_ops, tsp); 820 821 #ifdef KTRACE 822 if (ktruioin != NULL) { 823 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 824 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 825 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 826 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 827 } 828 #endif 829 830 return (error); 831 } 832 833 /* 834 * Copy 'count' items into the destination list pointed to by uap->eventlist. 835 */ 836 static int 837 kevent_copyout(void *arg, struct kevent *kevp, int count) 838 { 839 struct kevent_args *uap; 840 int error; 841 842 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 843 uap = (struct kevent_args *)arg; 844 845 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 846 if (error == 0) 847 uap->eventlist += count; 848 return (error); 849 } 850 851 /* 852 * Copy 'count' items from the list pointed to by uap->changelist. 853 */ 854 static int 855 kevent_copyin(void *arg, struct kevent *kevp, int count) 856 { 857 struct kevent_args *uap; 858 int error; 859 860 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 861 uap = (struct kevent_args *)arg; 862 863 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 864 if (error == 0) 865 uap->changelist += count; 866 return (error); 867 } 868 869 int 870 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 871 struct kevent_copyops *k_ops, const struct timespec *timeout) 872 { 873 cap_rights_t rights; 874 struct file *fp; 875 int error; 876 877 cap_rights_init(&rights); 878 if (nchanges > 0) 879 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 880 if (nevents > 0) 881 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 882 error = fget(td, fd, &rights, &fp); 883 if (error != 0) 884 return (error); 885 886 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 887 fdrop(fp, td); 888 889 return (error); 890 } 891 892 int 893 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 894 struct kevent_copyops *k_ops, const struct timespec *timeout) 895 { 896 struct kevent keva[KQ_NEVENTS]; 897 struct kevent *kevp, *changes; 898 struct kqueue *kq; 899 int i, n, nerrors, error; 900 901 error = kqueue_acquire(fp, &kq); 902 if (error != 0) 903 return (error); 904 905 nerrors = 0; 906 907 while (nchanges > 0) { 908 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 909 error = k_ops->k_copyin(k_ops->arg, keva, n); 910 if (error) 911 goto done; 912 changes = keva; 913 for (i = 0; i < n; i++) { 914 kevp = &changes[i]; 915 if (!kevp->filter) 916 continue; 917 kevp->flags &= ~EV_SYSFLAGS; 918 error = kqueue_register(kq, kevp, td, 1); 919 if (error || (kevp->flags & EV_RECEIPT)) { 920 if (nevents != 0) { 921 kevp->flags = EV_ERROR; 922 kevp->data = error; 923 (void) k_ops->k_copyout(k_ops->arg, 924 kevp, 1); 925 nevents--; 926 nerrors++; 927 } else { 928 goto done; 929 } 930 } 931 } 932 nchanges -= n; 933 } 934 if (nerrors) { 935 td->td_retval[0] = nerrors; 936 error = 0; 937 goto done; 938 } 939 940 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 941 done: 942 kqueue_release(kq, 0); 943 return (error); 944 } 945 946 int 947 kqueue_add_filteropts(int filt, struct filterops *filtops) 948 { 949 int error; 950 951 error = 0; 952 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 953 printf( 954 "trying to add a filterop that is out of range: %d is beyond %d\n", 955 ~filt, EVFILT_SYSCOUNT); 956 return EINVAL; 957 } 958 mtx_lock(&filterops_lock); 959 if (sysfilt_ops[~filt].for_fop != &null_filtops && 960 sysfilt_ops[~filt].for_fop != NULL) 961 error = EEXIST; 962 else { 963 sysfilt_ops[~filt].for_fop = filtops; 964 sysfilt_ops[~filt].for_refcnt = 0; 965 } 966 mtx_unlock(&filterops_lock); 967 968 return (error); 969 } 970 971 int 972 kqueue_del_filteropts(int filt) 973 { 974 int error; 975 976 error = 0; 977 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 978 return EINVAL; 979 980 mtx_lock(&filterops_lock); 981 if (sysfilt_ops[~filt].for_fop == &null_filtops || 982 sysfilt_ops[~filt].for_fop == NULL) 983 error = EINVAL; 984 else if (sysfilt_ops[~filt].for_refcnt != 0) 985 error = EBUSY; 986 else { 987 sysfilt_ops[~filt].for_fop = &null_filtops; 988 sysfilt_ops[~filt].for_refcnt = 0; 989 } 990 mtx_unlock(&filterops_lock); 991 992 return error; 993 } 994 995 static struct filterops * 996 kqueue_fo_find(int filt) 997 { 998 999 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1000 return NULL; 1001 1002 mtx_lock(&filterops_lock); 1003 sysfilt_ops[~filt].for_refcnt++; 1004 if (sysfilt_ops[~filt].for_fop == NULL) 1005 sysfilt_ops[~filt].for_fop = &null_filtops; 1006 mtx_unlock(&filterops_lock); 1007 1008 return sysfilt_ops[~filt].for_fop; 1009 } 1010 1011 static void 1012 kqueue_fo_release(int filt) 1013 { 1014 1015 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1016 return; 1017 1018 mtx_lock(&filterops_lock); 1019 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1020 ("filter object refcount not valid on release")); 1021 sysfilt_ops[~filt].for_refcnt--; 1022 mtx_unlock(&filterops_lock); 1023 } 1024 1025 /* 1026 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1027 * influence if memory allocation should wait. Make sure it is 0 if you 1028 * hold any mutexes. 1029 */ 1030 static int 1031 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1032 { 1033 struct filterops *fops; 1034 struct file *fp; 1035 struct knote *kn, *tkn; 1036 cap_rights_t rights; 1037 int error, filt, event; 1038 int haskqglobal, filedesc_unlock; 1039 1040 fp = NULL; 1041 kn = NULL; 1042 error = 0; 1043 haskqglobal = 0; 1044 filedesc_unlock = 0; 1045 1046 filt = kev->filter; 1047 fops = kqueue_fo_find(filt); 1048 if (fops == NULL) 1049 return EINVAL; 1050 1051 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1052 1053 findkn: 1054 if (fops->f_isfd) { 1055 KASSERT(td != NULL, ("td is NULL")); 1056 error = fget(td, kev->ident, 1057 cap_rights_init(&rights, CAP_EVENT), &fp); 1058 if (error) 1059 goto done; 1060 1061 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1062 kev->ident, 0) != 0) { 1063 /* try again */ 1064 fdrop(fp, td); 1065 fp = NULL; 1066 error = kqueue_expand(kq, fops, kev->ident, waitok); 1067 if (error) 1068 goto done; 1069 goto findkn; 1070 } 1071 1072 if (fp->f_type == DTYPE_KQUEUE) { 1073 /* 1074 * if we add some inteligence about what we are doing, 1075 * we should be able to support events on ourselves. 1076 * We need to know when we are doing this to prevent 1077 * getting both the knlist lock and the kq lock since 1078 * they are the same thing. 1079 */ 1080 if (fp->f_data == kq) { 1081 error = EINVAL; 1082 goto done; 1083 } 1084 1085 /* 1086 * Pre-lock the filedesc before the global 1087 * lock mutex, see the comment in 1088 * kqueue_close(). 1089 */ 1090 FILEDESC_XLOCK(td->td_proc->p_fd); 1091 filedesc_unlock = 1; 1092 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1093 } 1094 1095 KQ_LOCK(kq); 1096 if (kev->ident < kq->kq_knlistsize) { 1097 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1098 if (kev->filter == kn->kn_filter) 1099 break; 1100 } 1101 } else { 1102 if ((kev->flags & EV_ADD) == EV_ADD) 1103 kqueue_expand(kq, fops, kev->ident, waitok); 1104 1105 KQ_LOCK(kq); 1106 if (kq->kq_knhashmask != 0) { 1107 struct klist *list; 1108 1109 list = &kq->kq_knhash[ 1110 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1111 SLIST_FOREACH(kn, list, kn_link) 1112 if (kev->ident == kn->kn_id && 1113 kev->filter == kn->kn_filter) 1114 break; 1115 } 1116 } 1117 1118 /* knote is in the process of changing, wait for it to stablize. */ 1119 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1120 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1121 if (filedesc_unlock) { 1122 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1123 filedesc_unlock = 0; 1124 } 1125 kq->kq_state |= KQ_FLUXWAIT; 1126 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1127 if (fp != NULL) { 1128 fdrop(fp, td); 1129 fp = NULL; 1130 } 1131 goto findkn; 1132 } 1133 1134 /* 1135 * kn now contains the matching knote, or NULL if no match 1136 */ 1137 if (kn == NULL) { 1138 if (kev->flags & EV_ADD) { 1139 kn = tkn; 1140 tkn = NULL; 1141 if (kn == NULL) { 1142 KQ_UNLOCK(kq); 1143 error = ENOMEM; 1144 goto done; 1145 } 1146 kn->kn_fp = fp; 1147 kn->kn_kq = kq; 1148 kn->kn_fop = fops; 1149 /* 1150 * apply reference counts to knote structure, and 1151 * do not release it at the end of this routine. 1152 */ 1153 fops = NULL; 1154 fp = NULL; 1155 1156 kn->kn_sfflags = kev->fflags; 1157 kn->kn_sdata = kev->data; 1158 kev->fflags = 0; 1159 kev->data = 0; 1160 kn->kn_kevent = *kev; 1161 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1162 EV_ENABLE | EV_DISABLE); 1163 kn->kn_status = KN_INFLUX|KN_DETACHED; 1164 1165 error = knote_attach(kn, kq); 1166 KQ_UNLOCK(kq); 1167 if (error != 0) { 1168 tkn = kn; 1169 goto done; 1170 } 1171 1172 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1173 knote_drop(kn, td); 1174 goto done; 1175 } 1176 KN_LIST_LOCK(kn); 1177 goto done_ev_add; 1178 } else { 1179 /* No matching knote and the EV_ADD flag is not set. */ 1180 KQ_UNLOCK(kq); 1181 error = ENOENT; 1182 goto done; 1183 } 1184 } 1185 1186 if (kev->flags & EV_DELETE) { 1187 kn->kn_status |= KN_INFLUX; 1188 KQ_UNLOCK(kq); 1189 if (!(kn->kn_status & KN_DETACHED)) 1190 kn->kn_fop->f_detach(kn); 1191 knote_drop(kn, td); 1192 goto done; 1193 } 1194 1195 /* 1196 * The user may change some filter values after the initial EV_ADD, 1197 * but doing so will not reset any filter which has already been 1198 * triggered. 1199 */ 1200 kn->kn_status |= KN_INFLUX | KN_SCAN; 1201 KQ_UNLOCK(kq); 1202 KN_LIST_LOCK(kn); 1203 kn->kn_kevent.udata = kev->udata; 1204 if (!fops->f_isfd && fops->f_touch != NULL) { 1205 fops->f_touch(kn, kev, EVENT_REGISTER); 1206 } else { 1207 kn->kn_sfflags = kev->fflags; 1208 kn->kn_sdata = kev->data; 1209 } 1210 1211 /* 1212 * We can get here with kn->kn_knlist == NULL. This can happen when 1213 * the initial attach event decides that the event is "completed" 1214 * already. i.e. filt_procattach is called on a zombie process. It 1215 * will call filt_proc which will remove it from the list, and NULL 1216 * kn_knlist. 1217 */ 1218 done_ev_add: 1219 event = kn->kn_fop->f_event(kn, 0); 1220 KQ_LOCK(kq); 1221 if (event) 1222 KNOTE_ACTIVATE(kn, 1); 1223 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1224 KN_LIST_UNLOCK(kn); 1225 1226 if ((kev->flags & EV_DISABLE) && 1227 ((kn->kn_status & KN_DISABLED) == 0)) { 1228 kn->kn_status |= KN_DISABLED; 1229 } 1230 1231 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1232 kn->kn_status &= ~KN_DISABLED; 1233 if ((kn->kn_status & KN_ACTIVE) && 1234 ((kn->kn_status & KN_QUEUED) == 0)) 1235 knote_enqueue(kn); 1236 } 1237 KQ_UNLOCK_FLUX(kq); 1238 1239 done: 1240 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1241 if (filedesc_unlock) 1242 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1243 if (fp != NULL) 1244 fdrop(fp, td); 1245 if (tkn != NULL) 1246 knote_free(tkn); 1247 if (fops != NULL) 1248 kqueue_fo_release(filt); 1249 return (error); 1250 } 1251 1252 static int 1253 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1254 { 1255 int error; 1256 struct kqueue *kq; 1257 1258 error = 0; 1259 1260 kq = fp->f_data; 1261 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1262 return (EBADF); 1263 *kqp = kq; 1264 KQ_LOCK(kq); 1265 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1266 KQ_UNLOCK(kq); 1267 return (EBADF); 1268 } 1269 kq->kq_refcnt++; 1270 KQ_UNLOCK(kq); 1271 1272 return error; 1273 } 1274 1275 static void 1276 kqueue_release(struct kqueue *kq, int locked) 1277 { 1278 if (locked) 1279 KQ_OWNED(kq); 1280 else 1281 KQ_LOCK(kq); 1282 kq->kq_refcnt--; 1283 if (kq->kq_refcnt == 1) 1284 wakeup(&kq->kq_refcnt); 1285 if (!locked) 1286 KQ_UNLOCK(kq); 1287 } 1288 1289 static void 1290 kqueue_schedtask(struct kqueue *kq) 1291 { 1292 1293 KQ_OWNED(kq); 1294 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1295 ("scheduling kqueue task while draining")); 1296 1297 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1298 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1299 kq->kq_state |= KQ_TASKSCHED; 1300 } 1301 } 1302 1303 /* 1304 * Expand the kq to make sure we have storage for fops/ident pair. 1305 * 1306 * Return 0 on success (or no work necessary), return errno on failure. 1307 * 1308 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1309 * If kqueue_register is called from a non-fd context, there usually/should 1310 * be no locks held. 1311 */ 1312 static int 1313 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1314 int waitok) 1315 { 1316 struct klist *list, *tmp_knhash, *to_free; 1317 u_long tmp_knhashmask; 1318 int size; 1319 int fd; 1320 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1321 1322 KQ_NOTOWNED(kq); 1323 1324 to_free = NULL; 1325 if (fops->f_isfd) { 1326 fd = ident; 1327 if (kq->kq_knlistsize <= fd) { 1328 size = kq->kq_knlistsize; 1329 while (size <= fd) 1330 size += KQEXTENT; 1331 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1332 if (list == NULL) 1333 return ENOMEM; 1334 KQ_LOCK(kq); 1335 if (kq->kq_knlistsize > fd) { 1336 to_free = list; 1337 list = NULL; 1338 } else { 1339 if (kq->kq_knlist != NULL) { 1340 bcopy(kq->kq_knlist, list, 1341 kq->kq_knlistsize * sizeof(*list)); 1342 to_free = kq->kq_knlist; 1343 kq->kq_knlist = NULL; 1344 } 1345 bzero((caddr_t)list + 1346 kq->kq_knlistsize * sizeof(*list), 1347 (size - kq->kq_knlistsize) * sizeof(*list)); 1348 kq->kq_knlistsize = size; 1349 kq->kq_knlist = list; 1350 } 1351 KQ_UNLOCK(kq); 1352 } 1353 } else { 1354 if (kq->kq_knhashmask == 0) { 1355 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1356 &tmp_knhashmask); 1357 if (tmp_knhash == NULL) 1358 return ENOMEM; 1359 KQ_LOCK(kq); 1360 if (kq->kq_knhashmask == 0) { 1361 kq->kq_knhash = tmp_knhash; 1362 kq->kq_knhashmask = tmp_knhashmask; 1363 } else { 1364 to_free = tmp_knhash; 1365 } 1366 KQ_UNLOCK(kq); 1367 } 1368 } 1369 free(to_free, M_KQUEUE); 1370 1371 KQ_NOTOWNED(kq); 1372 return 0; 1373 } 1374 1375 static void 1376 kqueue_task(void *arg, int pending) 1377 { 1378 struct kqueue *kq; 1379 int haskqglobal; 1380 1381 haskqglobal = 0; 1382 kq = arg; 1383 1384 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1385 KQ_LOCK(kq); 1386 1387 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1388 1389 kq->kq_state &= ~KQ_TASKSCHED; 1390 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1391 wakeup(&kq->kq_state); 1392 } 1393 KQ_UNLOCK(kq); 1394 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1395 } 1396 1397 /* 1398 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1399 * We treat KN_MARKER knotes as if they are INFLUX. 1400 */ 1401 static int 1402 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1403 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1404 { 1405 struct kevent *kevp; 1406 struct knote *kn, *marker; 1407 sbintime_t asbt, rsbt; 1408 int count, error, haskqglobal, influx, nkev, touch; 1409 1410 count = maxevents; 1411 nkev = 0; 1412 error = 0; 1413 haskqglobal = 0; 1414 1415 if (maxevents == 0) 1416 goto done_nl; 1417 1418 rsbt = 0; 1419 if (tsp != NULL) { 1420 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1421 tsp->tv_nsec >= 1000000000) { 1422 error = EINVAL; 1423 goto done_nl; 1424 } 1425 if (timespecisset(tsp)) { 1426 if (tsp->tv_sec <= INT32_MAX) { 1427 rsbt = tstosbt(*tsp); 1428 if (TIMESEL(&asbt, rsbt)) 1429 asbt += tc_tick_sbt; 1430 if (asbt <= INT64_MAX - rsbt) 1431 asbt += rsbt; 1432 else 1433 asbt = 0; 1434 rsbt >>= tc_precexp; 1435 } else 1436 asbt = 0; 1437 } else 1438 asbt = -1; 1439 } else 1440 asbt = 0; 1441 marker = knote_alloc(1); 1442 if (marker == NULL) { 1443 error = ENOMEM; 1444 goto done_nl; 1445 } 1446 marker->kn_status = KN_MARKER; 1447 KQ_LOCK(kq); 1448 1449 retry: 1450 kevp = keva; 1451 if (kq->kq_count == 0) { 1452 if (asbt == -1) { 1453 error = EWOULDBLOCK; 1454 } else { 1455 kq->kq_state |= KQ_SLEEP; 1456 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1457 "kqread", asbt, rsbt, C_ABSOLUTE); 1458 } 1459 if (error == 0) 1460 goto retry; 1461 /* don't restart after signals... */ 1462 if (error == ERESTART) 1463 error = EINTR; 1464 else if (error == EWOULDBLOCK) 1465 error = 0; 1466 goto done; 1467 } 1468 1469 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1470 influx = 0; 1471 while (count) { 1472 KQ_OWNED(kq); 1473 kn = TAILQ_FIRST(&kq->kq_head); 1474 1475 if ((kn->kn_status == KN_MARKER && kn != marker) || 1476 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1477 if (influx) { 1478 influx = 0; 1479 KQ_FLUX_WAKEUP(kq); 1480 } 1481 kq->kq_state |= KQ_FLUXWAIT; 1482 error = msleep(kq, &kq->kq_lock, PSOCK, 1483 "kqflxwt", 0); 1484 continue; 1485 } 1486 1487 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1488 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1489 kn->kn_status &= ~KN_QUEUED; 1490 kq->kq_count--; 1491 continue; 1492 } 1493 if (kn == marker) { 1494 KQ_FLUX_WAKEUP(kq); 1495 if (count == maxevents) 1496 goto retry; 1497 goto done; 1498 } 1499 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1500 ("KN_INFLUX set when not suppose to be")); 1501 1502 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1503 kn->kn_status &= ~KN_QUEUED; 1504 kn->kn_status |= KN_INFLUX; 1505 kq->kq_count--; 1506 KQ_UNLOCK(kq); 1507 /* 1508 * We don't need to lock the list since we've marked 1509 * it _INFLUX. 1510 */ 1511 if (!(kn->kn_status & KN_DETACHED)) 1512 kn->kn_fop->f_detach(kn); 1513 knote_drop(kn, td); 1514 KQ_LOCK(kq); 1515 continue; 1516 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1517 kn->kn_status &= ~KN_QUEUED; 1518 kn->kn_status |= KN_INFLUX; 1519 kq->kq_count--; 1520 KQ_UNLOCK(kq); 1521 /* 1522 * We don't need to lock the list since we've marked 1523 * it _INFLUX. 1524 */ 1525 *kevp = kn->kn_kevent; 1526 if (!(kn->kn_status & KN_DETACHED)) 1527 kn->kn_fop->f_detach(kn); 1528 knote_drop(kn, td); 1529 KQ_LOCK(kq); 1530 kn = NULL; 1531 } else { 1532 kn->kn_status |= KN_INFLUX | KN_SCAN; 1533 KQ_UNLOCK(kq); 1534 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1535 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1536 KN_LIST_LOCK(kn); 1537 if (kn->kn_fop->f_event(kn, 0) == 0) { 1538 KQ_LOCK(kq); 1539 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1540 kn->kn_status &= 1541 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1542 KN_SCAN); 1543 kq->kq_count--; 1544 KN_LIST_UNLOCK(kn); 1545 influx = 1; 1546 continue; 1547 } 1548 touch = (!kn->kn_fop->f_isfd && 1549 kn->kn_fop->f_touch != NULL); 1550 if (touch) 1551 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1552 else 1553 *kevp = kn->kn_kevent; 1554 KQ_LOCK(kq); 1555 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1556 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1557 /* 1558 * Manually clear knotes who weren't 1559 * 'touch'ed. 1560 */ 1561 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1562 kn->kn_data = 0; 1563 kn->kn_fflags = 0; 1564 } 1565 if (kn->kn_flags & EV_DISPATCH) 1566 kn->kn_status |= KN_DISABLED; 1567 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1568 kq->kq_count--; 1569 } else 1570 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1571 1572 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1573 KN_LIST_UNLOCK(kn); 1574 influx = 1; 1575 } 1576 1577 /* we are returning a copy to the user */ 1578 kevp++; 1579 nkev++; 1580 count--; 1581 1582 if (nkev == KQ_NEVENTS) { 1583 influx = 0; 1584 KQ_UNLOCK_FLUX(kq); 1585 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1586 nkev = 0; 1587 kevp = keva; 1588 KQ_LOCK(kq); 1589 if (error) 1590 break; 1591 } 1592 } 1593 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1594 done: 1595 KQ_OWNED(kq); 1596 KQ_UNLOCK_FLUX(kq); 1597 knote_free(marker); 1598 done_nl: 1599 KQ_NOTOWNED(kq); 1600 if (nkev != 0) 1601 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1602 td->td_retval[0] = maxevents - count; 1603 return (error); 1604 } 1605 1606 /* 1607 * XXX 1608 * This could be expanded to call kqueue_scan, if desired. 1609 */ 1610 /*ARGSUSED*/ 1611 static int 1612 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1613 int flags, struct thread *td) 1614 { 1615 return (ENXIO); 1616 } 1617 1618 /*ARGSUSED*/ 1619 static int 1620 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1621 int flags, struct thread *td) 1622 { 1623 return (ENXIO); 1624 } 1625 1626 /*ARGSUSED*/ 1627 static int 1628 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1629 struct thread *td) 1630 { 1631 1632 return (EINVAL); 1633 } 1634 1635 /*ARGSUSED*/ 1636 static int 1637 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1638 struct ucred *active_cred, struct thread *td) 1639 { 1640 /* 1641 * Enabling sigio causes two major problems: 1642 * 1) infinite recursion: 1643 * Synopsys: kevent is being used to track signals and have FIOASYNC 1644 * set. On receipt of a signal this will cause a kqueue to recurse 1645 * into itself over and over. Sending the sigio causes the kqueue 1646 * to become ready, which in turn posts sigio again, forever. 1647 * Solution: this can be solved by setting a flag in the kqueue that 1648 * we have a SIGIO in progress. 1649 * 2) locking problems: 1650 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1651 * us above the proc and pgrp locks. 1652 * Solution: Post a signal using an async mechanism, being sure to 1653 * record a generation count in the delivery so that we do not deliver 1654 * a signal to the wrong process. 1655 * 1656 * Note, these two mechanisms are somewhat mutually exclusive! 1657 */ 1658 #if 0 1659 struct kqueue *kq; 1660 1661 kq = fp->f_data; 1662 switch (cmd) { 1663 case FIOASYNC: 1664 if (*(int *)data) { 1665 kq->kq_state |= KQ_ASYNC; 1666 } else { 1667 kq->kq_state &= ~KQ_ASYNC; 1668 } 1669 return (0); 1670 1671 case FIOSETOWN: 1672 return (fsetown(*(int *)data, &kq->kq_sigio)); 1673 1674 case FIOGETOWN: 1675 *(int *)data = fgetown(&kq->kq_sigio); 1676 return (0); 1677 } 1678 #endif 1679 1680 return (ENOTTY); 1681 } 1682 1683 /*ARGSUSED*/ 1684 static int 1685 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1686 struct thread *td) 1687 { 1688 struct kqueue *kq; 1689 int revents = 0; 1690 int error; 1691 1692 if ((error = kqueue_acquire(fp, &kq))) 1693 return POLLERR; 1694 1695 KQ_LOCK(kq); 1696 if (events & (POLLIN | POLLRDNORM)) { 1697 if (kq->kq_count) { 1698 revents |= events & (POLLIN | POLLRDNORM); 1699 } else { 1700 selrecord(td, &kq->kq_sel); 1701 if (SEL_WAITING(&kq->kq_sel)) 1702 kq->kq_state |= KQ_SEL; 1703 } 1704 } 1705 kqueue_release(kq, 1); 1706 KQ_UNLOCK(kq); 1707 return (revents); 1708 } 1709 1710 /*ARGSUSED*/ 1711 static int 1712 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1713 struct thread *td) 1714 { 1715 1716 bzero((void *)st, sizeof *st); 1717 /* 1718 * We no longer return kq_count because the unlocked value is useless. 1719 * If you spent all this time getting the count, why not spend your 1720 * syscall better by calling kevent? 1721 * 1722 * XXX - This is needed for libc_r. 1723 */ 1724 st->st_mode = S_IFIFO; 1725 return (0); 1726 } 1727 1728 /*ARGSUSED*/ 1729 static int 1730 kqueue_close(struct file *fp, struct thread *td) 1731 { 1732 struct kqueue *kq = fp->f_data; 1733 struct filedesc *fdp; 1734 struct knote *kn; 1735 int i; 1736 int error; 1737 int filedesc_unlock; 1738 1739 if ((error = kqueue_acquire(fp, &kq))) 1740 return error; 1741 1742 filedesc_unlock = 0; 1743 KQ_LOCK(kq); 1744 1745 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1746 ("kqueue already closing")); 1747 kq->kq_state |= KQ_CLOSING; 1748 if (kq->kq_refcnt > 1) 1749 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1750 1751 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1752 fdp = kq->kq_fdp; 1753 1754 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1755 ("kqueue's knlist not empty")); 1756 1757 for (i = 0; i < kq->kq_knlistsize; i++) { 1758 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1759 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1760 kq->kq_state |= KQ_FLUXWAIT; 1761 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1762 continue; 1763 } 1764 kn->kn_status |= KN_INFLUX; 1765 KQ_UNLOCK(kq); 1766 if (!(kn->kn_status & KN_DETACHED)) 1767 kn->kn_fop->f_detach(kn); 1768 knote_drop(kn, td); 1769 KQ_LOCK(kq); 1770 } 1771 } 1772 if (kq->kq_knhashmask != 0) { 1773 for (i = 0; i <= kq->kq_knhashmask; i++) { 1774 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1775 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1776 kq->kq_state |= KQ_FLUXWAIT; 1777 msleep(kq, &kq->kq_lock, PSOCK, 1778 "kqclo2", 0); 1779 continue; 1780 } 1781 kn->kn_status |= KN_INFLUX; 1782 KQ_UNLOCK(kq); 1783 if (!(kn->kn_status & KN_DETACHED)) 1784 kn->kn_fop->f_detach(kn); 1785 knote_drop(kn, td); 1786 KQ_LOCK(kq); 1787 } 1788 } 1789 } 1790 1791 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1792 kq->kq_state |= KQ_TASKDRAIN; 1793 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1794 } 1795 1796 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1797 selwakeuppri(&kq->kq_sel, PSOCK); 1798 if (!SEL_WAITING(&kq->kq_sel)) 1799 kq->kq_state &= ~KQ_SEL; 1800 } 1801 1802 KQ_UNLOCK(kq); 1803 1804 /* 1805 * We could be called due to the knote_drop() doing fdrop(), 1806 * called from kqueue_register(). In this case the global 1807 * lock is owned, and filedesc sx is locked before, to not 1808 * take the sleepable lock after non-sleepable. 1809 */ 1810 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1811 FILEDESC_XLOCK(fdp); 1812 filedesc_unlock = 1; 1813 } else 1814 filedesc_unlock = 0; 1815 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1816 if (filedesc_unlock) 1817 FILEDESC_XUNLOCK(fdp); 1818 1819 seldrain(&kq->kq_sel); 1820 knlist_destroy(&kq->kq_sel.si_note); 1821 mtx_destroy(&kq->kq_lock); 1822 kq->kq_fdp = NULL; 1823 1824 if (kq->kq_knhash != NULL) 1825 free(kq->kq_knhash, M_KQUEUE); 1826 if (kq->kq_knlist != NULL) 1827 free(kq->kq_knlist, M_KQUEUE); 1828 1829 funsetown(&kq->kq_sigio); 1830 free(kq, M_KQUEUE); 1831 fp->f_data = NULL; 1832 1833 return (0); 1834 } 1835 1836 static void 1837 kqueue_wakeup(struct kqueue *kq) 1838 { 1839 KQ_OWNED(kq); 1840 1841 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1842 kq->kq_state &= ~KQ_SLEEP; 1843 wakeup(kq); 1844 } 1845 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1846 selwakeuppri(&kq->kq_sel, PSOCK); 1847 if (!SEL_WAITING(&kq->kq_sel)) 1848 kq->kq_state &= ~KQ_SEL; 1849 } 1850 if (!knlist_empty(&kq->kq_sel.si_note)) 1851 kqueue_schedtask(kq); 1852 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1853 pgsigio(&kq->kq_sigio, SIGIO, 0); 1854 } 1855 } 1856 1857 /* 1858 * Walk down a list of knotes, activating them if their event has triggered. 1859 * 1860 * There is a possibility to optimize in the case of one kq watching another. 1861 * Instead of scheduling a task to wake it up, you could pass enough state 1862 * down the chain to make up the parent kqueue. Make this code functional 1863 * first. 1864 */ 1865 void 1866 knote(struct knlist *list, long hint, int lockflags) 1867 { 1868 struct kqueue *kq; 1869 struct knote *kn, *tkn; 1870 int error; 1871 1872 if (list == NULL) 1873 return; 1874 1875 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1876 1877 if ((lockflags & KNF_LISTLOCKED) == 0) 1878 list->kl_lock(list->kl_lockarg); 1879 1880 /* 1881 * If we unlock the list lock (and set KN_INFLUX), we can 1882 * eliminate the kqueue scheduling, but this will introduce 1883 * four lock/unlock's for each knote to test. Also, marker 1884 * would be needed to keep iteration position, since filters 1885 * or other threads could remove events. 1886 */ 1887 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 1888 kq = kn->kn_kq; 1889 KQ_LOCK(kq); 1890 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1891 /* 1892 * Do not process the influx notes, except for 1893 * the influx coming from the kq unlock in the 1894 * kqueue_scan(). In the later case, we do 1895 * not interfere with the scan, since the code 1896 * fragment in kqueue_scan() locks the knlist, 1897 * and cannot proceed until we finished. 1898 */ 1899 KQ_UNLOCK(kq); 1900 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1901 kn->kn_status |= KN_INFLUX; 1902 KQ_UNLOCK(kq); 1903 error = kn->kn_fop->f_event(kn, hint); 1904 KQ_LOCK(kq); 1905 kn->kn_status &= ~KN_INFLUX; 1906 if (error) 1907 KNOTE_ACTIVATE(kn, 1); 1908 KQ_UNLOCK_FLUX(kq); 1909 } else { 1910 kn->kn_status |= KN_HASKQLOCK; 1911 if (kn->kn_fop->f_event(kn, hint)) 1912 KNOTE_ACTIVATE(kn, 1); 1913 kn->kn_status &= ~KN_HASKQLOCK; 1914 KQ_UNLOCK(kq); 1915 } 1916 } 1917 if ((lockflags & KNF_LISTLOCKED) == 0) 1918 list->kl_unlock(list->kl_lockarg); 1919 } 1920 1921 /* 1922 * add a knote to a knlist 1923 */ 1924 void 1925 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1926 { 1927 KNL_ASSERT_LOCK(knl, islocked); 1928 KQ_NOTOWNED(kn->kn_kq); 1929 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1930 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1931 if (!islocked) 1932 knl->kl_lock(knl->kl_lockarg); 1933 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1934 if (!islocked) 1935 knl->kl_unlock(knl->kl_lockarg); 1936 KQ_LOCK(kn->kn_kq); 1937 kn->kn_knlist = knl; 1938 kn->kn_status &= ~KN_DETACHED; 1939 KQ_UNLOCK(kn->kn_kq); 1940 } 1941 1942 static void 1943 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1944 { 1945 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1946 KNL_ASSERT_LOCK(knl, knlislocked); 1947 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1948 if (!kqislocked) 1949 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1950 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1951 if (!knlislocked) 1952 knl->kl_lock(knl->kl_lockarg); 1953 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1954 kn->kn_knlist = NULL; 1955 if (!knlislocked) 1956 knl->kl_unlock(knl->kl_lockarg); 1957 if (!kqislocked) 1958 KQ_LOCK(kn->kn_kq); 1959 kn->kn_status |= KN_DETACHED; 1960 if (!kqislocked) 1961 KQ_UNLOCK(kn->kn_kq); 1962 } 1963 1964 /* 1965 * remove knote from the specified knlist 1966 */ 1967 void 1968 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1969 { 1970 1971 knlist_remove_kq(knl, kn, islocked, 0); 1972 } 1973 1974 /* 1975 * remove knote from the specified knlist while in f_event handler. 1976 */ 1977 void 1978 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1979 { 1980 1981 knlist_remove_kq(knl, kn, 1, 1982 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1983 } 1984 1985 int 1986 knlist_empty(struct knlist *knl) 1987 { 1988 1989 KNL_ASSERT_LOCKED(knl); 1990 return SLIST_EMPTY(&knl->kl_list); 1991 } 1992 1993 static struct mtx knlist_lock; 1994 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1995 MTX_DEF); 1996 static void knlist_mtx_lock(void *arg); 1997 static void knlist_mtx_unlock(void *arg); 1998 1999 static void 2000 knlist_mtx_lock(void *arg) 2001 { 2002 2003 mtx_lock((struct mtx *)arg); 2004 } 2005 2006 static void 2007 knlist_mtx_unlock(void *arg) 2008 { 2009 2010 mtx_unlock((struct mtx *)arg); 2011 } 2012 2013 static void 2014 knlist_mtx_assert_locked(void *arg) 2015 { 2016 2017 mtx_assert((struct mtx *)arg, MA_OWNED); 2018 } 2019 2020 static void 2021 knlist_mtx_assert_unlocked(void *arg) 2022 { 2023 2024 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2025 } 2026 2027 static void 2028 knlist_rw_rlock(void *arg) 2029 { 2030 2031 rw_rlock((struct rwlock *)arg); 2032 } 2033 2034 static void 2035 knlist_rw_runlock(void *arg) 2036 { 2037 2038 rw_runlock((struct rwlock *)arg); 2039 } 2040 2041 static void 2042 knlist_rw_assert_locked(void *arg) 2043 { 2044 2045 rw_assert((struct rwlock *)arg, RA_LOCKED); 2046 } 2047 2048 static void 2049 knlist_rw_assert_unlocked(void *arg) 2050 { 2051 2052 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2053 } 2054 2055 void 2056 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2057 void (*kl_unlock)(void *), 2058 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2059 { 2060 2061 if (lock == NULL) 2062 knl->kl_lockarg = &knlist_lock; 2063 else 2064 knl->kl_lockarg = lock; 2065 2066 if (kl_lock == NULL) 2067 knl->kl_lock = knlist_mtx_lock; 2068 else 2069 knl->kl_lock = kl_lock; 2070 if (kl_unlock == NULL) 2071 knl->kl_unlock = knlist_mtx_unlock; 2072 else 2073 knl->kl_unlock = kl_unlock; 2074 if (kl_assert_locked == NULL) 2075 knl->kl_assert_locked = knlist_mtx_assert_locked; 2076 else 2077 knl->kl_assert_locked = kl_assert_locked; 2078 if (kl_assert_unlocked == NULL) 2079 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2080 else 2081 knl->kl_assert_unlocked = kl_assert_unlocked; 2082 2083 SLIST_INIT(&knl->kl_list); 2084 } 2085 2086 void 2087 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2088 { 2089 2090 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2091 } 2092 2093 void 2094 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2095 { 2096 2097 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2098 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2099 } 2100 2101 void 2102 knlist_destroy(struct knlist *knl) 2103 { 2104 2105 #ifdef INVARIANTS 2106 /* 2107 * if we run across this error, we need to find the offending 2108 * driver and have it call knlist_clear or knlist_delete. 2109 */ 2110 if (!SLIST_EMPTY(&knl->kl_list)) 2111 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2112 #endif 2113 2114 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2115 SLIST_INIT(&knl->kl_list); 2116 } 2117 2118 /* 2119 * Even if we are locked, we may need to drop the lock to allow any influx 2120 * knotes time to "settle". 2121 */ 2122 void 2123 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2124 { 2125 struct knote *kn, *kn2; 2126 struct kqueue *kq; 2127 2128 if (islocked) 2129 KNL_ASSERT_LOCKED(knl); 2130 else { 2131 KNL_ASSERT_UNLOCKED(knl); 2132 again: /* need to reacquire lock since we have dropped it */ 2133 knl->kl_lock(knl->kl_lockarg); 2134 } 2135 2136 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2137 kq = kn->kn_kq; 2138 KQ_LOCK(kq); 2139 if ((kn->kn_status & KN_INFLUX)) { 2140 KQ_UNLOCK(kq); 2141 continue; 2142 } 2143 knlist_remove_kq(knl, kn, 1, 1); 2144 if (killkn) { 2145 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2146 KQ_UNLOCK(kq); 2147 knote_drop(kn, td); 2148 } else { 2149 /* Make sure cleared knotes disappear soon */ 2150 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2151 KQ_UNLOCK(kq); 2152 } 2153 kq = NULL; 2154 } 2155 2156 if (!SLIST_EMPTY(&knl->kl_list)) { 2157 /* there are still KN_INFLUX remaining */ 2158 kn = SLIST_FIRST(&knl->kl_list); 2159 kq = kn->kn_kq; 2160 KQ_LOCK(kq); 2161 KASSERT(kn->kn_status & KN_INFLUX, 2162 ("knote removed w/o list lock")); 2163 knl->kl_unlock(knl->kl_lockarg); 2164 kq->kq_state |= KQ_FLUXWAIT; 2165 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2166 kq = NULL; 2167 goto again; 2168 } 2169 2170 if (islocked) 2171 KNL_ASSERT_LOCKED(knl); 2172 else { 2173 knl->kl_unlock(knl->kl_lockarg); 2174 KNL_ASSERT_UNLOCKED(knl); 2175 } 2176 } 2177 2178 /* 2179 * Remove all knotes referencing a specified fd must be called with FILEDESC 2180 * lock. This prevents a race where a new fd comes along and occupies the 2181 * entry and we attach a knote to the fd. 2182 */ 2183 void 2184 knote_fdclose(struct thread *td, int fd) 2185 { 2186 struct filedesc *fdp = td->td_proc->p_fd; 2187 struct kqueue *kq; 2188 struct knote *kn; 2189 int influx; 2190 2191 FILEDESC_XLOCK_ASSERT(fdp); 2192 2193 /* 2194 * We shouldn't have to worry about new kevents appearing on fd 2195 * since filedesc is locked. 2196 */ 2197 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2198 KQ_LOCK(kq); 2199 2200 again: 2201 influx = 0; 2202 while (kq->kq_knlistsize > fd && 2203 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2204 if (kn->kn_status & KN_INFLUX) { 2205 /* someone else might be waiting on our knote */ 2206 if (influx) 2207 wakeup(kq); 2208 kq->kq_state |= KQ_FLUXWAIT; 2209 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2210 goto again; 2211 } 2212 kn->kn_status |= KN_INFLUX; 2213 KQ_UNLOCK(kq); 2214 if (!(kn->kn_status & KN_DETACHED)) 2215 kn->kn_fop->f_detach(kn); 2216 knote_drop(kn, td); 2217 influx = 1; 2218 KQ_LOCK(kq); 2219 } 2220 KQ_UNLOCK_FLUX(kq); 2221 } 2222 } 2223 2224 static int 2225 knote_attach(struct knote *kn, struct kqueue *kq) 2226 { 2227 struct klist *list; 2228 2229 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2230 KQ_OWNED(kq); 2231 2232 if (kn->kn_fop->f_isfd) { 2233 if (kn->kn_id >= kq->kq_knlistsize) 2234 return ENOMEM; 2235 list = &kq->kq_knlist[kn->kn_id]; 2236 } else { 2237 if (kq->kq_knhash == NULL) 2238 return ENOMEM; 2239 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2240 } 2241 2242 SLIST_INSERT_HEAD(list, kn, kn_link); 2243 2244 return 0; 2245 } 2246 2247 /* 2248 * knote must already have been detached using the f_detach method. 2249 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2250 * to prevent other removal. 2251 */ 2252 static void 2253 knote_drop(struct knote *kn, struct thread *td) 2254 { 2255 struct kqueue *kq; 2256 struct klist *list; 2257 2258 kq = kn->kn_kq; 2259 2260 KQ_NOTOWNED(kq); 2261 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2262 ("knote_drop called without KN_INFLUX set in kn_status")); 2263 2264 KQ_LOCK(kq); 2265 if (kn->kn_fop->f_isfd) 2266 list = &kq->kq_knlist[kn->kn_id]; 2267 else 2268 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2269 2270 if (!SLIST_EMPTY(list)) 2271 SLIST_REMOVE(list, kn, knote, kn_link); 2272 if (kn->kn_status & KN_QUEUED) 2273 knote_dequeue(kn); 2274 KQ_UNLOCK_FLUX(kq); 2275 2276 if (kn->kn_fop->f_isfd) { 2277 fdrop(kn->kn_fp, td); 2278 kn->kn_fp = NULL; 2279 } 2280 kqueue_fo_release(kn->kn_kevent.filter); 2281 kn->kn_fop = NULL; 2282 knote_free(kn); 2283 } 2284 2285 static void 2286 knote_enqueue(struct knote *kn) 2287 { 2288 struct kqueue *kq = kn->kn_kq; 2289 2290 KQ_OWNED(kn->kn_kq); 2291 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2292 2293 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2294 kn->kn_status |= KN_QUEUED; 2295 kq->kq_count++; 2296 kqueue_wakeup(kq); 2297 } 2298 2299 static void 2300 knote_dequeue(struct knote *kn) 2301 { 2302 struct kqueue *kq = kn->kn_kq; 2303 2304 KQ_OWNED(kn->kn_kq); 2305 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2306 2307 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2308 kn->kn_status &= ~KN_QUEUED; 2309 kq->kq_count--; 2310 } 2311 2312 static void 2313 knote_init(void) 2314 { 2315 2316 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2317 NULL, NULL, UMA_ALIGN_PTR, 0); 2318 } 2319 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2320 2321 static struct knote * 2322 knote_alloc(int waitok) 2323 { 2324 return ((struct knote *)uma_zalloc(knote_zone, 2325 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2326 } 2327 2328 static void 2329 knote_free(struct knote *kn) 2330 { 2331 if (kn != NULL) 2332 uma_zfree(knote_zone, kn); 2333 } 2334 2335 /* 2336 * Register the kev w/ the kq specified by fd. 2337 */ 2338 int 2339 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2340 { 2341 struct kqueue *kq; 2342 struct file *fp; 2343 cap_rights_t rights; 2344 int error; 2345 2346 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2347 if (error != 0) 2348 return (error); 2349 if ((error = kqueue_acquire(fp, &kq)) != 0) 2350 goto noacquire; 2351 2352 error = kqueue_register(kq, kev, td, waitok); 2353 2354 kqueue_release(kq, 0); 2355 2356 noacquire: 2357 fdrop(fp, td); 2358 2359 return error; 2360 }
Cache object: 1ece525eb1adff80b8246bb6c2d76fc2
[ source navigation ] [ diff markup ] [ identifier search ] [ freetext search ] [ file search ] [ list types ] [ track identifier ]