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 * 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/10.1/sys/kern/kern_event.c 264368 2014-04-12 14:08:53Z kib $"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/capability.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 static __inline sbintime_t 526 timer2sbintime(intptr_t data) 527 { 528 529 return (SBT_1MS * data); 530 } 531 532 static void 533 filt_timerexpire(void *knx) 534 { 535 struct callout *calloutp; 536 struct knote *kn; 537 538 kn = knx; 539 kn->kn_data++; 540 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 541 542 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 543 calloutp = (struct callout *)kn->kn_hook; 544 callout_reset_sbt_on(calloutp, 545 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 546 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 547 } 548 } 549 550 /* 551 * data contains amount of time to sleep, in milliseconds 552 */ 553 static int 554 filt_timerattach(struct knote *kn) 555 { 556 struct callout *calloutp; 557 sbintime_t to; 558 unsigned int ncallouts; 559 560 if ((intptr_t)kn->kn_sdata < 0) 561 return (EINVAL); 562 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 563 kn->kn_sdata = 1; 564 to = timer2sbintime(kn->kn_sdata); 565 if (to < 0) 566 return (EINVAL); 567 568 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 569 do { 570 if (ncallouts >= kq_calloutmax) 571 return (ENOMEM); 572 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 573 &ncallouts, ncallouts + 1, memory_order_relaxed, 574 memory_order_relaxed)); 575 576 kn->kn_flags |= EV_CLEAR; /* automatically set */ 577 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 578 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 579 callout_init(calloutp, CALLOUT_MPSAFE); 580 kn->kn_hook = calloutp; 581 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 582 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 583 584 return (0); 585 } 586 587 static void 588 filt_timerdetach(struct knote *kn) 589 { 590 struct callout *calloutp; 591 unsigned int old; 592 593 calloutp = (struct callout *)kn->kn_hook; 594 callout_drain(calloutp); 595 free(calloutp, M_KQUEUE); 596 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 597 KASSERT(old > 0, ("Number of callouts cannot become negative")); 598 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 599 } 600 601 static int 602 filt_timer(struct knote *kn, long hint) 603 { 604 605 return (kn->kn_data != 0); 606 } 607 608 static int 609 filt_userattach(struct knote *kn) 610 { 611 612 /* 613 * EVFILT_USER knotes are not attached to anything in the kernel. 614 */ 615 kn->kn_hook = NULL; 616 if (kn->kn_fflags & NOTE_TRIGGER) 617 kn->kn_hookid = 1; 618 else 619 kn->kn_hookid = 0; 620 return (0); 621 } 622 623 static void 624 filt_userdetach(__unused struct knote *kn) 625 { 626 627 /* 628 * EVFILT_USER knotes are not attached to anything in the kernel. 629 */ 630 } 631 632 static int 633 filt_user(struct knote *kn, __unused long hint) 634 { 635 636 return (kn->kn_hookid); 637 } 638 639 static void 640 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 641 { 642 u_int ffctrl; 643 644 switch (type) { 645 case EVENT_REGISTER: 646 if (kev->fflags & NOTE_TRIGGER) 647 kn->kn_hookid = 1; 648 649 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 650 kev->fflags &= NOTE_FFLAGSMASK; 651 switch (ffctrl) { 652 case NOTE_FFNOP: 653 break; 654 655 case NOTE_FFAND: 656 kn->kn_sfflags &= kev->fflags; 657 break; 658 659 case NOTE_FFOR: 660 kn->kn_sfflags |= kev->fflags; 661 break; 662 663 case NOTE_FFCOPY: 664 kn->kn_sfflags = kev->fflags; 665 break; 666 667 default: 668 /* XXX Return error? */ 669 break; 670 } 671 kn->kn_sdata = kev->data; 672 if (kev->flags & EV_CLEAR) { 673 kn->kn_hookid = 0; 674 kn->kn_data = 0; 675 kn->kn_fflags = 0; 676 } 677 break; 678 679 case EVENT_PROCESS: 680 *kev = kn->kn_kevent; 681 kev->fflags = kn->kn_sfflags; 682 kev->data = kn->kn_sdata; 683 if (kn->kn_flags & EV_CLEAR) { 684 kn->kn_hookid = 0; 685 kn->kn_data = 0; 686 kn->kn_fflags = 0; 687 } 688 break; 689 690 default: 691 panic("filt_usertouch() - invalid type (%ld)", type); 692 break; 693 } 694 } 695 696 int 697 sys_kqueue(struct thread *td, struct kqueue_args *uap) 698 { 699 struct filedesc *fdp; 700 struct kqueue *kq; 701 struct file *fp; 702 int fd, error; 703 704 fdp = td->td_proc->p_fd; 705 error = falloc(td, &fp, &fd, 0); 706 if (error) 707 goto done2; 708 709 /* An extra reference on `fp' has been held for us by falloc(). */ 710 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 711 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 712 TAILQ_INIT(&kq->kq_head); 713 kq->kq_fdp = fdp; 714 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 715 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 716 717 FILEDESC_XLOCK(fdp); 718 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 719 FILEDESC_XUNLOCK(fdp); 720 721 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 722 fdrop(fp, td); 723 724 td->td_retval[0] = fd; 725 done2: 726 return (error); 727 } 728 729 #ifndef _SYS_SYSPROTO_H_ 730 struct kevent_args { 731 int fd; 732 const struct kevent *changelist; 733 int nchanges; 734 struct kevent *eventlist; 735 int nevents; 736 const struct timespec *timeout; 737 }; 738 #endif 739 int 740 sys_kevent(struct thread *td, struct kevent_args *uap) 741 { 742 struct timespec ts, *tsp; 743 struct kevent_copyops k_ops = { uap, 744 kevent_copyout, 745 kevent_copyin}; 746 int error; 747 #ifdef KTRACE 748 struct uio ktruio; 749 struct iovec ktriov; 750 struct uio *ktruioin = NULL; 751 struct uio *ktruioout = NULL; 752 #endif 753 754 if (uap->timeout != NULL) { 755 error = copyin(uap->timeout, &ts, sizeof(ts)); 756 if (error) 757 return (error); 758 tsp = &ts; 759 } else 760 tsp = NULL; 761 762 #ifdef KTRACE 763 if (KTRPOINT(td, KTR_GENIO)) { 764 ktriov.iov_base = uap->changelist; 765 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 766 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 767 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 768 .uio_td = td }; 769 ktruioin = cloneuio(&ktruio); 770 ktriov.iov_base = uap->eventlist; 771 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 772 ktruioout = cloneuio(&ktruio); 773 } 774 #endif 775 776 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 777 &k_ops, tsp); 778 779 #ifdef KTRACE 780 if (ktruioin != NULL) { 781 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 782 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 783 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 784 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 785 } 786 #endif 787 788 return (error); 789 } 790 791 /* 792 * Copy 'count' items into the destination list pointed to by uap->eventlist. 793 */ 794 static int 795 kevent_copyout(void *arg, struct kevent *kevp, int count) 796 { 797 struct kevent_args *uap; 798 int error; 799 800 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 801 uap = (struct kevent_args *)arg; 802 803 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 804 if (error == 0) 805 uap->eventlist += count; 806 return (error); 807 } 808 809 /* 810 * Copy 'count' items from the list pointed to by uap->changelist. 811 */ 812 static int 813 kevent_copyin(void *arg, struct kevent *kevp, int count) 814 { 815 struct kevent_args *uap; 816 int error; 817 818 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 819 uap = (struct kevent_args *)arg; 820 821 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 822 if (error == 0) 823 uap->changelist += count; 824 return (error); 825 } 826 827 int 828 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 829 struct kevent_copyops *k_ops, const struct timespec *timeout) 830 { 831 struct kevent keva[KQ_NEVENTS]; 832 struct kevent *kevp, *changes; 833 struct kqueue *kq; 834 struct file *fp; 835 cap_rights_t rights; 836 int i, n, nerrors, error; 837 838 cap_rights_init(&rights); 839 if (nchanges > 0) 840 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 841 if (nevents > 0) 842 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 843 error = fget(td, fd, &rights, &fp); 844 if (error != 0) 845 return (error); 846 847 error = kqueue_acquire(fp, &kq); 848 if (error != 0) 849 goto done_norel; 850 851 nerrors = 0; 852 853 while (nchanges > 0) { 854 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 855 error = k_ops->k_copyin(k_ops->arg, keva, n); 856 if (error) 857 goto done; 858 changes = keva; 859 for (i = 0; i < n; i++) { 860 kevp = &changes[i]; 861 if (!kevp->filter) 862 continue; 863 kevp->flags &= ~EV_SYSFLAGS; 864 error = kqueue_register(kq, kevp, td, 1); 865 if (error || (kevp->flags & EV_RECEIPT)) { 866 if (nevents != 0) { 867 kevp->flags = EV_ERROR; 868 kevp->data = error; 869 (void) k_ops->k_copyout(k_ops->arg, 870 kevp, 1); 871 nevents--; 872 nerrors++; 873 } else { 874 goto done; 875 } 876 } 877 } 878 nchanges -= n; 879 } 880 if (nerrors) { 881 td->td_retval[0] = nerrors; 882 error = 0; 883 goto done; 884 } 885 886 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 887 done: 888 kqueue_release(kq, 0); 889 done_norel: 890 fdrop(fp, td); 891 return (error); 892 } 893 894 int 895 kqueue_add_filteropts(int filt, struct filterops *filtops) 896 { 897 int error; 898 899 error = 0; 900 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 901 printf( 902 "trying to add a filterop that is out of range: %d is beyond %d\n", 903 ~filt, EVFILT_SYSCOUNT); 904 return EINVAL; 905 } 906 mtx_lock(&filterops_lock); 907 if (sysfilt_ops[~filt].for_fop != &null_filtops && 908 sysfilt_ops[~filt].for_fop != NULL) 909 error = EEXIST; 910 else { 911 sysfilt_ops[~filt].for_fop = filtops; 912 sysfilt_ops[~filt].for_refcnt = 0; 913 } 914 mtx_unlock(&filterops_lock); 915 916 return (error); 917 } 918 919 int 920 kqueue_del_filteropts(int filt) 921 { 922 int error; 923 924 error = 0; 925 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 926 return EINVAL; 927 928 mtx_lock(&filterops_lock); 929 if (sysfilt_ops[~filt].for_fop == &null_filtops || 930 sysfilt_ops[~filt].for_fop == NULL) 931 error = EINVAL; 932 else if (sysfilt_ops[~filt].for_refcnt != 0) 933 error = EBUSY; 934 else { 935 sysfilt_ops[~filt].for_fop = &null_filtops; 936 sysfilt_ops[~filt].for_refcnt = 0; 937 } 938 mtx_unlock(&filterops_lock); 939 940 return error; 941 } 942 943 static struct filterops * 944 kqueue_fo_find(int filt) 945 { 946 947 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 948 return NULL; 949 950 mtx_lock(&filterops_lock); 951 sysfilt_ops[~filt].for_refcnt++; 952 if (sysfilt_ops[~filt].for_fop == NULL) 953 sysfilt_ops[~filt].for_fop = &null_filtops; 954 mtx_unlock(&filterops_lock); 955 956 return sysfilt_ops[~filt].for_fop; 957 } 958 959 static void 960 kqueue_fo_release(int filt) 961 { 962 963 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 964 return; 965 966 mtx_lock(&filterops_lock); 967 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 968 ("filter object refcount not valid on release")); 969 sysfilt_ops[~filt].for_refcnt--; 970 mtx_unlock(&filterops_lock); 971 } 972 973 /* 974 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 975 * influence if memory allocation should wait. Make sure it is 0 if you 976 * hold any mutexes. 977 */ 978 static int 979 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 980 { 981 struct filterops *fops; 982 struct file *fp; 983 struct knote *kn, *tkn; 984 cap_rights_t rights; 985 int error, filt, event; 986 int haskqglobal, filedesc_unlock; 987 988 fp = NULL; 989 kn = NULL; 990 error = 0; 991 haskqglobal = 0; 992 filedesc_unlock = 0; 993 994 filt = kev->filter; 995 fops = kqueue_fo_find(filt); 996 if (fops == NULL) 997 return EINVAL; 998 999 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1000 1001 findkn: 1002 if (fops->f_isfd) { 1003 KASSERT(td != NULL, ("td is NULL")); 1004 error = fget(td, kev->ident, 1005 cap_rights_init(&rights, CAP_EVENT), &fp); 1006 if (error) 1007 goto done; 1008 1009 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1010 kev->ident, 0) != 0) { 1011 /* try again */ 1012 fdrop(fp, td); 1013 fp = NULL; 1014 error = kqueue_expand(kq, fops, kev->ident, waitok); 1015 if (error) 1016 goto done; 1017 goto findkn; 1018 } 1019 1020 if (fp->f_type == DTYPE_KQUEUE) { 1021 /* 1022 * if we add some inteligence about what we are doing, 1023 * we should be able to support events on ourselves. 1024 * We need to know when we are doing this to prevent 1025 * getting both the knlist lock and the kq lock since 1026 * they are the same thing. 1027 */ 1028 if (fp->f_data == kq) { 1029 error = EINVAL; 1030 goto done; 1031 } 1032 1033 /* 1034 * Pre-lock the filedesc before the global 1035 * lock mutex, see the comment in 1036 * kqueue_close(). 1037 */ 1038 FILEDESC_XLOCK(td->td_proc->p_fd); 1039 filedesc_unlock = 1; 1040 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1041 } 1042 1043 KQ_LOCK(kq); 1044 if (kev->ident < kq->kq_knlistsize) { 1045 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1046 if (kev->filter == kn->kn_filter) 1047 break; 1048 } 1049 } else { 1050 if ((kev->flags & EV_ADD) == EV_ADD) 1051 kqueue_expand(kq, fops, kev->ident, waitok); 1052 1053 KQ_LOCK(kq); 1054 if (kq->kq_knhashmask != 0) { 1055 struct klist *list; 1056 1057 list = &kq->kq_knhash[ 1058 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1059 SLIST_FOREACH(kn, list, kn_link) 1060 if (kev->ident == kn->kn_id && 1061 kev->filter == kn->kn_filter) 1062 break; 1063 } 1064 } 1065 1066 /* knote is in the process of changing, wait for it to stablize. */ 1067 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1068 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1069 if (filedesc_unlock) { 1070 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1071 filedesc_unlock = 0; 1072 } 1073 kq->kq_state |= KQ_FLUXWAIT; 1074 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1075 if (fp != NULL) { 1076 fdrop(fp, td); 1077 fp = NULL; 1078 } 1079 goto findkn; 1080 } 1081 1082 /* 1083 * kn now contains the matching knote, or NULL if no match 1084 */ 1085 if (kn == NULL) { 1086 if (kev->flags & EV_ADD) { 1087 kn = tkn; 1088 tkn = NULL; 1089 if (kn == NULL) { 1090 KQ_UNLOCK(kq); 1091 error = ENOMEM; 1092 goto done; 1093 } 1094 kn->kn_fp = fp; 1095 kn->kn_kq = kq; 1096 kn->kn_fop = fops; 1097 /* 1098 * apply reference counts to knote structure, and 1099 * do not release it at the end of this routine. 1100 */ 1101 fops = NULL; 1102 fp = NULL; 1103 1104 kn->kn_sfflags = kev->fflags; 1105 kn->kn_sdata = kev->data; 1106 kev->fflags = 0; 1107 kev->data = 0; 1108 kn->kn_kevent = *kev; 1109 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1110 EV_ENABLE | EV_DISABLE); 1111 kn->kn_status = KN_INFLUX|KN_DETACHED; 1112 1113 error = knote_attach(kn, kq); 1114 KQ_UNLOCK(kq); 1115 if (error != 0) { 1116 tkn = kn; 1117 goto done; 1118 } 1119 1120 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1121 knote_drop(kn, td); 1122 goto done; 1123 } 1124 KN_LIST_LOCK(kn); 1125 goto done_ev_add; 1126 } else { 1127 /* No matching knote and the EV_ADD flag is not set. */ 1128 KQ_UNLOCK(kq); 1129 error = ENOENT; 1130 goto done; 1131 } 1132 } 1133 1134 if (kev->flags & EV_DELETE) { 1135 kn->kn_status |= KN_INFLUX; 1136 KQ_UNLOCK(kq); 1137 if (!(kn->kn_status & KN_DETACHED)) 1138 kn->kn_fop->f_detach(kn); 1139 knote_drop(kn, td); 1140 goto done; 1141 } 1142 1143 /* 1144 * The user may change some filter values after the initial EV_ADD, 1145 * but doing so will not reset any filter which has already been 1146 * triggered. 1147 */ 1148 kn->kn_status |= KN_INFLUX | KN_SCAN; 1149 KQ_UNLOCK(kq); 1150 KN_LIST_LOCK(kn); 1151 kn->kn_kevent.udata = kev->udata; 1152 if (!fops->f_isfd && fops->f_touch != NULL) { 1153 fops->f_touch(kn, kev, EVENT_REGISTER); 1154 } else { 1155 kn->kn_sfflags = kev->fflags; 1156 kn->kn_sdata = kev->data; 1157 } 1158 1159 /* 1160 * We can get here with kn->kn_knlist == NULL. This can happen when 1161 * the initial attach event decides that the event is "completed" 1162 * already. i.e. filt_procattach is called on a zombie process. It 1163 * will call filt_proc which will remove it from the list, and NULL 1164 * kn_knlist. 1165 */ 1166 done_ev_add: 1167 event = kn->kn_fop->f_event(kn, 0); 1168 KQ_LOCK(kq); 1169 if (event) 1170 KNOTE_ACTIVATE(kn, 1); 1171 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1172 KN_LIST_UNLOCK(kn); 1173 1174 if ((kev->flags & EV_DISABLE) && 1175 ((kn->kn_status & KN_DISABLED) == 0)) { 1176 kn->kn_status |= KN_DISABLED; 1177 } 1178 1179 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1180 kn->kn_status &= ~KN_DISABLED; 1181 if ((kn->kn_status & KN_ACTIVE) && 1182 ((kn->kn_status & KN_QUEUED) == 0)) 1183 knote_enqueue(kn); 1184 } 1185 KQ_UNLOCK_FLUX(kq); 1186 1187 done: 1188 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1189 if (filedesc_unlock) 1190 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1191 if (fp != NULL) 1192 fdrop(fp, td); 1193 if (tkn != NULL) 1194 knote_free(tkn); 1195 if (fops != NULL) 1196 kqueue_fo_release(filt); 1197 return (error); 1198 } 1199 1200 static int 1201 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1202 { 1203 int error; 1204 struct kqueue *kq; 1205 1206 error = 0; 1207 1208 kq = fp->f_data; 1209 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1210 return (EBADF); 1211 *kqp = kq; 1212 KQ_LOCK(kq); 1213 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1214 KQ_UNLOCK(kq); 1215 return (EBADF); 1216 } 1217 kq->kq_refcnt++; 1218 KQ_UNLOCK(kq); 1219 1220 return error; 1221 } 1222 1223 static void 1224 kqueue_release(struct kqueue *kq, int locked) 1225 { 1226 if (locked) 1227 KQ_OWNED(kq); 1228 else 1229 KQ_LOCK(kq); 1230 kq->kq_refcnt--; 1231 if (kq->kq_refcnt == 1) 1232 wakeup(&kq->kq_refcnt); 1233 if (!locked) 1234 KQ_UNLOCK(kq); 1235 } 1236 1237 static void 1238 kqueue_schedtask(struct kqueue *kq) 1239 { 1240 1241 KQ_OWNED(kq); 1242 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1243 ("scheduling kqueue task while draining")); 1244 1245 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1246 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1247 kq->kq_state |= KQ_TASKSCHED; 1248 } 1249 } 1250 1251 /* 1252 * Expand the kq to make sure we have storage for fops/ident pair. 1253 * 1254 * Return 0 on success (or no work necessary), return errno on failure. 1255 * 1256 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1257 * If kqueue_register is called from a non-fd context, there usually/should 1258 * be no locks held. 1259 */ 1260 static int 1261 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1262 int waitok) 1263 { 1264 struct klist *list, *tmp_knhash, *to_free; 1265 u_long tmp_knhashmask; 1266 int size; 1267 int fd; 1268 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1269 1270 KQ_NOTOWNED(kq); 1271 1272 to_free = NULL; 1273 if (fops->f_isfd) { 1274 fd = ident; 1275 if (kq->kq_knlistsize <= fd) { 1276 size = kq->kq_knlistsize; 1277 while (size <= fd) 1278 size += KQEXTENT; 1279 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1280 if (list == NULL) 1281 return ENOMEM; 1282 KQ_LOCK(kq); 1283 if (kq->kq_knlistsize > fd) { 1284 to_free = list; 1285 list = NULL; 1286 } else { 1287 if (kq->kq_knlist != NULL) { 1288 bcopy(kq->kq_knlist, list, 1289 kq->kq_knlistsize * sizeof(*list)); 1290 to_free = kq->kq_knlist; 1291 kq->kq_knlist = NULL; 1292 } 1293 bzero((caddr_t)list + 1294 kq->kq_knlistsize * sizeof(*list), 1295 (size - kq->kq_knlistsize) * sizeof(*list)); 1296 kq->kq_knlistsize = size; 1297 kq->kq_knlist = list; 1298 } 1299 KQ_UNLOCK(kq); 1300 } 1301 } else { 1302 if (kq->kq_knhashmask == 0) { 1303 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1304 &tmp_knhashmask); 1305 if (tmp_knhash == NULL) 1306 return ENOMEM; 1307 KQ_LOCK(kq); 1308 if (kq->kq_knhashmask == 0) { 1309 kq->kq_knhash = tmp_knhash; 1310 kq->kq_knhashmask = tmp_knhashmask; 1311 } else { 1312 to_free = tmp_knhash; 1313 } 1314 KQ_UNLOCK(kq); 1315 } 1316 } 1317 free(to_free, M_KQUEUE); 1318 1319 KQ_NOTOWNED(kq); 1320 return 0; 1321 } 1322 1323 static void 1324 kqueue_task(void *arg, int pending) 1325 { 1326 struct kqueue *kq; 1327 int haskqglobal; 1328 1329 haskqglobal = 0; 1330 kq = arg; 1331 1332 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1333 KQ_LOCK(kq); 1334 1335 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1336 1337 kq->kq_state &= ~KQ_TASKSCHED; 1338 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1339 wakeup(&kq->kq_state); 1340 } 1341 KQ_UNLOCK(kq); 1342 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1343 } 1344 1345 /* 1346 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1347 * We treat KN_MARKER knotes as if they are INFLUX. 1348 */ 1349 static int 1350 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1351 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1352 { 1353 struct kevent *kevp; 1354 struct knote *kn, *marker; 1355 sbintime_t asbt, rsbt; 1356 int count, error, haskqglobal, influx, nkev, touch; 1357 1358 count = maxevents; 1359 nkev = 0; 1360 error = 0; 1361 haskqglobal = 0; 1362 1363 if (maxevents == 0) 1364 goto done_nl; 1365 1366 rsbt = 0; 1367 if (tsp != NULL) { 1368 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1369 tsp->tv_nsec >= 1000000000) { 1370 error = EINVAL; 1371 goto done_nl; 1372 } 1373 if (timespecisset(tsp)) { 1374 if (tsp->tv_sec <= INT32_MAX) { 1375 rsbt = tstosbt(*tsp); 1376 if (TIMESEL(&asbt, rsbt)) 1377 asbt += tc_tick_sbt; 1378 if (asbt <= INT64_MAX - rsbt) 1379 asbt += rsbt; 1380 else 1381 asbt = 0; 1382 rsbt >>= tc_precexp; 1383 } else 1384 asbt = 0; 1385 } else 1386 asbt = -1; 1387 } else 1388 asbt = 0; 1389 marker = knote_alloc(1); 1390 if (marker == NULL) { 1391 error = ENOMEM; 1392 goto done_nl; 1393 } 1394 marker->kn_status = KN_MARKER; 1395 KQ_LOCK(kq); 1396 1397 retry: 1398 kevp = keva; 1399 if (kq->kq_count == 0) { 1400 if (asbt == -1) { 1401 error = EWOULDBLOCK; 1402 } else { 1403 kq->kq_state |= KQ_SLEEP; 1404 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1405 "kqread", asbt, rsbt, C_ABSOLUTE); 1406 } 1407 if (error == 0) 1408 goto retry; 1409 /* don't restart after signals... */ 1410 if (error == ERESTART) 1411 error = EINTR; 1412 else if (error == EWOULDBLOCK) 1413 error = 0; 1414 goto done; 1415 } 1416 1417 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1418 influx = 0; 1419 while (count) { 1420 KQ_OWNED(kq); 1421 kn = TAILQ_FIRST(&kq->kq_head); 1422 1423 if ((kn->kn_status == KN_MARKER && kn != marker) || 1424 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1425 if (influx) { 1426 influx = 0; 1427 KQ_FLUX_WAKEUP(kq); 1428 } 1429 kq->kq_state |= KQ_FLUXWAIT; 1430 error = msleep(kq, &kq->kq_lock, PSOCK, 1431 "kqflxwt", 0); 1432 continue; 1433 } 1434 1435 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1436 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1437 kn->kn_status &= ~KN_QUEUED; 1438 kq->kq_count--; 1439 continue; 1440 } 1441 if (kn == marker) { 1442 KQ_FLUX_WAKEUP(kq); 1443 if (count == maxevents) 1444 goto retry; 1445 goto done; 1446 } 1447 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1448 ("KN_INFLUX set when not suppose to be")); 1449 1450 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1451 kn->kn_status &= ~KN_QUEUED; 1452 kn->kn_status |= KN_INFLUX; 1453 kq->kq_count--; 1454 KQ_UNLOCK(kq); 1455 /* 1456 * We don't need to lock the list since we've marked 1457 * it _INFLUX. 1458 */ 1459 if (!(kn->kn_status & KN_DETACHED)) 1460 kn->kn_fop->f_detach(kn); 1461 knote_drop(kn, td); 1462 KQ_LOCK(kq); 1463 continue; 1464 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1465 kn->kn_status &= ~KN_QUEUED; 1466 kn->kn_status |= KN_INFLUX; 1467 kq->kq_count--; 1468 KQ_UNLOCK(kq); 1469 /* 1470 * We don't need to lock the list since we've marked 1471 * it _INFLUX. 1472 */ 1473 *kevp = kn->kn_kevent; 1474 if (!(kn->kn_status & KN_DETACHED)) 1475 kn->kn_fop->f_detach(kn); 1476 knote_drop(kn, td); 1477 KQ_LOCK(kq); 1478 kn = NULL; 1479 } else { 1480 kn->kn_status |= KN_INFLUX | KN_SCAN; 1481 KQ_UNLOCK(kq); 1482 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1483 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1484 KN_LIST_LOCK(kn); 1485 if (kn->kn_fop->f_event(kn, 0) == 0) { 1486 KQ_LOCK(kq); 1487 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1488 kn->kn_status &= 1489 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1490 KN_SCAN); 1491 kq->kq_count--; 1492 KN_LIST_UNLOCK(kn); 1493 influx = 1; 1494 continue; 1495 } 1496 touch = (!kn->kn_fop->f_isfd && 1497 kn->kn_fop->f_touch != NULL); 1498 if (touch) 1499 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1500 else 1501 *kevp = kn->kn_kevent; 1502 KQ_LOCK(kq); 1503 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1504 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1505 /* 1506 * Manually clear knotes who weren't 1507 * 'touch'ed. 1508 */ 1509 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1510 kn->kn_data = 0; 1511 kn->kn_fflags = 0; 1512 } 1513 if (kn->kn_flags & EV_DISPATCH) 1514 kn->kn_status |= KN_DISABLED; 1515 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1516 kq->kq_count--; 1517 } else 1518 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1519 1520 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1521 KN_LIST_UNLOCK(kn); 1522 influx = 1; 1523 } 1524 1525 /* we are returning a copy to the user */ 1526 kevp++; 1527 nkev++; 1528 count--; 1529 1530 if (nkev == KQ_NEVENTS) { 1531 influx = 0; 1532 KQ_UNLOCK_FLUX(kq); 1533 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1534 nkev = 0; 1535 kevp = keva; 1536 KQ_LOCK(kq); 1537 if (error) 1538 break; 1539 } 1540 } 1541 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1542 done: 1543 KQ_OWNED(kq); 1544 KQ_UNLOCK_FLUX(kq); 1545 knote_free(marker); 1546 done_nl: 1547 KQ_NOTOWNED(kq); 1548 if (nkev != 0) 1549 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1550 td->td_retval[0] = maxevents - count; 1551 return (error); 1552 } 1553 1554 /* 1555 * XXX 1556 * This could be expanded to call kqueue_scan, if desired. 1557 */ 1558 /*ARGSUSED*/ 1559 static int 1560 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1561 int flags, struct thread *td) 1562 { 1563 return (ENXIO); 1564 } 1565 1566 /*ARGSUSED*/ 1567 static int 1568 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1569 int flags, struct thread *td) 1570 { 1571 return (ENXIO); 1572 } 1573 1574 /*ARGSUSED*/ 1575 static int 1576 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1577 struct thread *td) 1578 { 1579 1580 return (EINVAL); 1581 } 1582 1583 /*ARGSUSED*/ 1584 static int 1585 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1586 struct ucred *active_cred, struct thread *td) 1587 { 1588 /* 1589 * Enabling sigio causes two major problems: 1590 * 1) infinite recursion: 1591 * Synopsys: kevent is being used to track signals and have FIOASYNC 1592 * set. On receipt of a signal this will cause a kqueue to recurse 1593 * into itself over and over. Sending the sigio causes the kqueue 1594 * to become ready, which in turn posts sigio again, forever. 1595 * Solution: this can be solved by setting a flag in the kqueue that 1596 * we have a SIGIO in progress. 1597 * 2) locking problems: 1598 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1599 * us above the proc and pgrp locks. 1600 * Solution: Post a signal using an async mechanism, being sure to 1601 * record a generation count in the delivery so that we do not deliver 1602 * a signal to the wrong process. 1603 * 1604 * Note, these two mechanisms are somewhat mutually exclusive! 1605 */ 1606 #if 0 1607 struct kqueue *kq; 1608 1609 kq = fp->f_data; 1610 switch (cmd) { 1611 case FIOASYNC: 1612 if (*(int *)data) { 1613 kq->kq_state |= KQ_ASYNC; 1614 } else { 1615 kq->kq_state &= ~KQ_ASYNC; 1616 } 1617 return (0); 1618 1619 case FIOSETOWN: 1620 return (fsetown(*(int *)data, &kq->kq_sigio)); 1621 1622 case FIOGETOWN: 1623 *(int *)data = fgetown(&kq->kq_sigio); 1624 return (0); 1625 } 1626 #endif 1627 1628 return (ENOTTY); 1629 } 1630 1631 /*ARGSUSED*/ 1632 static int 1633 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1634 struct thread *td) 1635 { 1636 struct kqueue *kq; 1637 int revents = 0; 1638 int error; 1639 1640 if ((error = kqueue_acquire(fp, &kq))) 1641 return POLLERR; 1642 1643 KQ_LOCK(kq); 1644 if (events & (POLLIN | POLLRDNORM)) { 1645 if (kq->kq_count) { 1646 revents |= events & (POLLIN | POLLRDNORM); 1647 } else { 1648 selrecord(td, &kq->kq_sel); 1649 if (SEL_WAITING(&kq->kq_sel)) 1650 kq->kq_state |= KQ_SEL; 1651 } 1652 } 1653 kqueue_release(kq, 1); 1654 KQ_UNLOCK(kq); 1655 return (revents); 1656 } 1657 1658 /*ARGSUSED*/ 1659 static int 1660 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1661 struct thread *td) 1662 { 1663 1664 bzero((void *)st, sizeof *st); 1665 /* 1666 * We no longer return kq_count because the unlocked value is useless. 1667 * If you spent all this time getting the count, why not spend your 1668 * syscall better by calling kevent? 1669 * 1670 * XXX - This is needed for libc_r. 1671 */ 1672 st->st_mode = S_IFIFO; 1673 return (0); 1674 } 1675 1676 /*ARGSUSED*/ 1677 static int 1678 kqueue_close(struct file *fp, struct thread *td) 1679 { 1680 struct kqueue *kq = fp->f_data; 1681 struct filedesc *fdp; 1682 struct knote *kn; 1683 int i; 1684 int error; 1685 int filedesc_unlock; 1686 1687 if ((error = kqueue_acquire(fp, &kq))) 1688 return error; 1689 1690 filedesc_unlock = 0; 1691 KQ_LOCK(kq); 1692 1693 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1694 ("kqueue already closing")); 1695 kq->kq_state |= KQ_CLOSING; 1696 if (kq->kq_refcnt > 1) 1697 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1698 1699 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1700 fdp = kq->kq_fdp; 1701 1702 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1703 ("kqueue's knlist not empty")); 1704 1705 for (i = 0; i < kq->kq_knlistsize; i++) { 1706 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1707 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1708 kq->kq_state |= KQ_FLUXWAIT; 1709 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1710 continue; 1711 } 1712 kn->kn_status |= KN_INFLUX; 1713 KQ_UNLOCK(kq); 1714 if (!(kn->kn_status & KN_DETACHED)) 1715 kn->kn_fop->f_detach(kn); 1716 knote_drop(kn, td); 1717 KQ_LOCK(kq); 1718 } 1719 } 1720 if (kq->kq_knhashmask != 0) { 1721 for (i = 0; i <= kq->kq_knhashmask; i++) { 1722 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1723 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1724 kq->kq_state |= KQ_FLUXWAIT; 1725 msleep(kq, &kq->kq_lock, PSOCK, 1726 "kqclo2", 0); 1727 continue; 1728 } 1729 kn->kn_status |= KN_INFLUX; 1730 KQ_UNLOCK(kq); 1731 if (!(kn->kn_status & KN_DETACHED)) 1732 kn->kn_fop->f_detach(kn); 1733 knote_drop(kn, td); 1734 KQ_LOCK(kq); 1735 } 1736 } 1737 } 1738 1739 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1740 kq->kq_state |= KQ_TASKDRAIN; 1741 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1742 } 1743 1744 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1745 selwakeuppri(&kq->kq_sel, PSOCK); 1746 if (!SEL_WAITING(&kq->kq_sel)) 1747 kq->kq_state &= ~KQ_SEL; 1748 } 1749 1750 KQ_UNLOCK(kq); 1751 1752 /* 1753 * We could be called due to the knote_drop() doing fdrop(), 1754 * called from kqueue_register(). In this case the global 1755 * lock is owned, and filedesc sx is locked before, to not 1756 * take the sleepable lock after non-sleepable. 1757 */ 1758 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1759 FILEDESC_XLOCK(fdp); 1760 filedesc_unlock = 1; 1761 } else 1762 filedesc_unlock = 0; 1763 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1764 if (filedesc_unlock) 1765 FILEDESC_XUNLOCK(fdp); 1766 1767 seldrain(&kq->kq_sel); 1768 knlist_destroy(&kq->kq_sel.si_note); 1769 mtx_destroy(&kq->kq_lock); 1770 kq->kq_fdp = NULL; 1771 1772 if (kq->kq_knhash != NULL) 1773 free(kq->kq_knhash, M_KQUEUE); 1774 if (kq->kq_knlist != NULL) 1775 free(kq->kq_knlist, M_KQUEUE); 1776 1777 funsetown(&kq->kq_sigio); 1778 free(kq, M_KQUEUE); 1779 fp->f_data = NULL; 1780 1781 return (0); 1782 } 1783 1784 static void 1785 kqueue_wakeup(struct kqueue *kq) 1786 { 1787 KQ_OWNED(kq); 1788 1789 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1790 kq->kq_state &= ~KQ_SLEEP; 1791 wakeup(kq); 1792 } 1793 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1794 selwakeuppri(&kq->kq_sel, PSOCK); 1795 if (!SEL_WAITING(&kq->kq_sel)) 1796 kq->kq_state &= ~KQ_SEL; 1797 } 1798 if (!knlist_empty(&kq->kq_sel.si_note)) 1799 kqueue_schedtask(kq); 1800 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1801 pgsigio(&kq->kq_sigio, SIGIO, 0); 1802 } 1803 } 1804 1805 /* 1806 * Walk down a list of knotes, activating them if their event has triggered. 1807 * 1808 * There is a possibility to optimize in the case of one kq watching another. 1809 * Instead of scheduling a task to wake it up, you could pass enough state 1810 * down the chain to make up the parent kqueue. Make this code functional 1811 * first. 1812 */ 1813 void 1814 knote(struct knlist *list, long hint, int lockflags) 1815 { 1816 struct kqueue *kq; 1817 struct knote *kn; 1818 int error; 1819 1820 if (list == NULL) 1821 return; 1822 1823 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1824 1825 if ((lockflags & KNF_LISTLOCKED) == 0) 1826 list->kl_lock(list->kl_lockarg); 1827 1828 /* 1829 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1830 * the kqueue scheduling, but this will introduce four 1831 * lock/unlock's for each knote to test. If we do, continue to use 1832 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1833 * only safe if you want to remove the current item, which we are 1834 * not doing. 1835 */ 1836 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1837 kq = kn->kn_kq; 1838 KQ_LOCK(kq); 1839 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1840 /* 1841 * Do not process the influx notes, except for 1842 * the influx coming from the kq unlock in the 1843 * kqueue_scan(). In the later case, we do 1844 * not interfere with the scan, since the code 1845 * fragment in kqueue_scan() locks the knlist, 1846 * and cannot proceed until we finished. 1847 */ 1848 KQ_UNLOCK(kq); 1849 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1850 kn->kn_status |= KN_INFLUX; 1851 KQ_UNLOCK(kq); 1852 error = kn->kn_fop->f_event(kn, hint); 1853 KQ_LOCK(kq); 1854 kn->kn_status &= ~KN_INFLUX; 1855 if (error) 1856 KNOTE_ACTIVATE(kn, 1); 1857 KQ_UNLOCK_FLUX(kq); 1858 } else { 1859 kn->kn_status |= KN_HASKQLOCK; 1860 if (kn->kn_fop->f_event(kn, hint)) 1861 KNOTE_ACTIVATE(kn, 1); 1862 kn->kn_status &= ~KN_HASKQLOCK; 1863 KQ_UNLOCK(kq); 1864 } 1865 } 1866 if ((lockflags & KNF_LISTLOCKED) == 0) 1867 list->kl_unlock(list->kl_lockarg); 1868 } 1869 1870 /* 1871 * add a knote to a knlist 1872 */ 1873 void 1874 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1875 { 1876 KNL_ASSERT_LOCK(knl, islocked); 1877 KQ_NOTOWNED(kn->kn_kq); 1878 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1879 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1880 if (!islocked) 1881 knl->kl_lock(knl->kl_lockarg); 1882 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1883 if (!islocked) 1884 knl->kl_unlock(knl->kl_lockarg); 1885 KQ_LOCK(kn->kn_kq); 1886 kn->kn_knlist = knl; 1887 kn->kn_status &= ~KN_DETACHED; 1888 KQ_UNLOCK(kn->kn_kq); 1889 } 1890 1891 static void 1892 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1893 { 1894 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1895 KNL_ASSERT_LOCK(knl, knlislocked); 1896 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1897 if (!kqislocked) 1898 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1899 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1900 if (!knlislocked) 1901 knl->kl_lock(knl->kl_lockarg); 1902 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1903 kn->kn_knlist = NULL; 1904 if (!knlislocked) 1905 knl->kl_unlock(knl->kl_lockarg); 1906 if (!kqislocked) 1907 KQ_LOCK(kn->kn_kq); 1908 kn->kn_status |= KN_DETACHED; 1909 if (!kqislocked) 1910 KQ_UNLOCK(kn->kn_kq); 1911 } 1912 1913 /* 1914 * remove knote from the specified knlist 1915 */ 1916 void 1917 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1918 { 1919 1920 knlist_remove_kq(knl, kn, islocked, 0); 1921 } 1922 1923 /* 1924 * remove knote from the specified knlist while in f_event handler. 1925 */ 1926 void 1927 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1928 { 1929 1930 knlist_remove_kq(knl, kn, 1, 1931 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1932 } 1933 1934 int 1935 knlist_empty(struct knlist *knl) 1936 { 1937 1938 KNL_ASSERT_LOCKED(knl); 1939 return SLIST_EMPTY(&knl->kl_list); 1940 } 1941 1942 static struct mtx knlist_lock; 1943 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1944 MTX_DEF); 1945 static void knlist_mtx_lock(void *arg); 1946 static void knlist_mtx_unlock(void *arg); 1947 1948 static void 1949 knlist_mtx_lock(void *arg) 1950 { 1951 1952 mtx_lock((struct mtx *)arg); 1953 } 1954 1955 static void 1956 knlist_mtx_unlock(void *arg) 1957 { 1958 1959 mtx_unlock((struct mtx *)arg); 1960 } 1961 1962 static void 1963 knlist_mtx_assert_locked(void *arg) 1964 { 1965 1966 mtx_assert((struct mtx *)arg, MA_OWNED); 1967 } 1968 1969 static void 1970 knlist_mtx_assert_unlocked(void *arg) 1971 { 1972 1973 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1974 } 1975 1976 static void 1977 knlist_rw_rlock(void *arg) 1978 { 1979 1980 rw_rlock((struct rwlock *)arg); 1981 } 1982 1983 static void 1984 knlist_rw_runlock(void *arg) 1985 { 1986 1987 rw_runlock((struct rwlock *)arg); 1988 } 1989 1990 static void 1991 knlist_rw_assert_locked(void *arg) 1992 { 1993 1994 rw_assert((struct rwlock *)arg, RA_LOCKED); 1995 } 1996 1997 static void 1998 knlist_rw_assert_unlocked(void *arg) 1999 { 2000 2001 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2002 } 2003 2004 void 2005 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2006 void (*kl_unlock)(void *), 2007 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2008 { 2009 2010 if (lock == NULL) 2011 knl->kl_lockarg = &knlist_lock; 2012 else 2013 knl->kl_lockarg = lock; 2014 2015 if (kl_lock == NULL) 2016 knl->kl_lock = knlist_mtx_lock; 2017 else 2018 knl->kl_lock = kl_lock; 2019 if (kl_unlock == NULL) 2020 knl->kl_unlock = knlist_mtx_unlock; 2021 else 2022 knl->kl_unlock = kl_unlock; 2023 if (kl_assert_locked == NULL) 2024 knl->kl_assert_locked = knlist_mtx_assert_locked; 2025 else 2026 knl->kl_assert_locked = kl_assert_locked; 2027 if (kl_assert_unlocked == NULL) 2028 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2029 else 2030 knl->kl_assert_unlocked = kl_assert_unlocked; 2031 2032 SLIST_INIT(&knl->kl_list); 2033 } 2034 2035 void 2036 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2037 { 2038 2039 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2040 } 2041 2042 void 2043 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2044 { 2045 2046 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2047 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2048 } 2049 2050 void 2051 knlist_destroy(struct knlist *knl) 2052 { 2053 2054 #ifdef INVARIANTS 2055 /* 2056 * if we run across this error, we need to find the offending 2057 * driver and have it call knlist_clear or knlist_delete. 2058 */ 2059 if (!SLIST_EMPTY(&knl->kl_list)) 2060 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2061 #endif 2062 2063 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2064 SLIST_INIT(&knl->kl_list); 2065 } 2066 2067 /* 2068 * Even if we are locked, we may need to drop the lock to allow any influx 2069 * knotes time to "settle". 2070 */ 2071 void 2072 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2073 { 2074 struct knote *kn, *kn2; 2075 struct kqueue *kq; 2076 2077 if (islocked) 2078 KNL_ASSERT_LOCKED(knl); 2079 else { 2080 KNL_ASSERT_UNLOCKED(knl); 2081 again: /* need to reacquire lock since we have dropped it */ 2082 knl->kl_lock(knl->kl_lockarg); 2083 } 2084 2085 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2086 kq = kn->kn_kq; 2087 KQ_LOCK(kq); 2088 if ((kn->kn_status & KN_INFLUX)) { 2089 KQ_UNLOCK(kq); 2090 continue; 2091 } 2092 knlist_remove_kq(knl, kn, 1, 1); 2093 if (killkn) { 2094 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2095 KQ_UNLOCK(kq); 2096 knote_drop(kn, td); 2097 } else { 2098 /* Make sure cleared knotes disappear soon */ 2099 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2100 KQ_UNLOCK(kq); 2101 } 2102 kq = NULL; 2103 } 2104 2105 if (!SLIST_EMPTY(&knl->kl_list)) { 2106 /* there are still KN_INFLUX remaining */ 2107 kn = SLIST_FIRST(&knl->kl_list); 2108 kq = kn->kn_kq; 2109 KQ_LOCK(kq); 2110 KASSERT(kn->kn_status & KN_INFLUX, 2111 ("knote removed w/o list lock")); 2112 knl->kl_unlock(knl->kl_lockarg); 2113 kq->kq_state |= KQ_FLUXWAIT; 2114 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2115 kq = NULL; 2116 goto again; 2117 } 2118 2119 if (islocked) 2120 KNL_ASSERT_LOCKED(knl); 2121 else { 2122 knl->kl_unlock(knl->kl_lockarg); 2123 KNL_ASSERT_UNLOCKED(knl); 2124 } 2125 } 2126 2127 /* 2128 * Remove all knotes referencing a specified fd must be called with FILEDESC 2129 * lock. This prevents a race where a new fd comes along and occupies the 2130 * entry and we attach a knote to the fd. 2131 */ 2132 void 2133 knote_fdclose(struct thread *td, int fd) 2134 { 2135 struct filedesc *fdp = td->td_proc->p_fd; 2136 struct kqueue *kq; 2137 struct knote *kn; 2138 int influx; 2139 2140 FILEDESC_XLOCK_ASSERT(fdp); 2141 2142 /* 2143 * We shouldn't have to worry about new kevents appearing on fd 2144 * since filedesc is locked. 2145 */ 2146 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2147 KQ_LOCK(kq); 2148 2149 again: 2150 influx = 0; 2151 while (kq->kq_knlistsize > fd && 2152 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2153 if (kn->kn_status & KN_INFLUX) { 2154 /* someone else might be waiting on our knote */ 2155 if (influx) 2156 wakeup(kq); 2157 kq->kq_state |= KQ_FLUXWAIT; 2158 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2159 goto again; 2160 } 2161 kn->kn_status |= KN_INFLUX; 2162 KQ_UNLOCK(kq); 2163 if (!(kn->kn_status & KN_DETACHED)) 2164 kn->kn_fop->f_detach(kn); 2165 knote_drop(kn, td); 2166 influx = 1; 2167 KQ_LOCK(kq); 2168 } 2169 KQ_UNLOCK_FLUX(kq); 2170 } 2171 } 2172 2173 static int 2174 knote_attach(struct knote *kn, struct kqueue *kq) 2175 { 2176 struct klist *list; 2177 2178 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2179 KQ_OWNED(kq); 2180 2181 if (kn->kn_fop->f_isfd) { 2182 if (kn->kn_id >= kq->kq_knlistsize) 2183 return ENOMEM; 2184 list = &kq->kq_knlist[kn->kn_id]; 2185 } else { 2186 if (kq->kq_knhash == NULL) 2187 return ENOMEM; 2188 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2189 } 2190 2191 SLIST_INSERT_HEAD(list, kn, kn_link); 2192 2193 return 0; 2194 } 2195 2196 /* 2197 * knote must already have been detached using the f_detach method. 2198 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2199 * to prevent other removal. 2200 */ 2201 static void 2202 knote_drop(struct knote *kn, struct thread *td) 2203 { 2204 struct kqueue *kq; 2205 struct klist *list; 2206 2207 kq = kn->kn_kq; 2208 2209 KQ_NOTOWNED(kq); 2210 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2211 ("knote_drop called without KN_INFLUX set in kn_status")); 2212 2213 KQ_LOCK(kq); 2214 if (kn->kn_fop->f_isfd) 2215 list = &kq->kq_knlist[kn->kn_id]; 2216 else 2217 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2218 2219 if (!SLIST_EMPTY(list)) 2220 SLIST_REMOVE(list, kn, knote, kn_link); 2221 if (kn->kn_status & KN_QUEUED) 2222 knote_dequeue(kn); 2223 KQ_UNLOCK_FLUX(kq); 2224 2225 if (kn->kn_fop->f_isfd) { 2226 fdrop(kn->kn_fp, td); 2227 kn->kn_fp = NULL; 2228 } 2229 kqueue_fo_release(kn->kn_kevent.filter); 2230 kn->kn_fop = NULL; 2231 knote_free(kn); 2232 } 2233 2234 static void 2235 knote_enqueue(struct knote *kn) 2236 { 2237 struct kqueue *kq = kn->kn_kq; 2238 2239 KQ_OWNED(kn->kn_kq); 2240 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2241 2242 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2243 kn->kn_status |= KN_QUEUED; 2244 kq->kq_count++; 2245 kqueue_wakeup(kq); 2246 } 2247 2248 static void 2249 knote_dequeue(struct knote *kn) 2250 { 2251 struct kqueue *kq = kn->kn_kq; 2252 2253 KQ_OWNED(kn->kn_kq); 2254 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2255 2256 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2257 kn->kn_status &= ~KN_QUEUED; 2258 kq->kq_count--; 2259 } 2260 2261 static void 2262 knote_init(void) 2263 { 2264 2265 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2266 NULL, NULL, UMA_ALIGN_PTR, 0); 2267 } 2268 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2269 2270 static struct knote * 2271 knote_alloc(int waitok) 2272 { 2273 return ((struct knote *)uma_zalloc(knote_zone, 2274 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2275 } 2276 2277 static void 2278 knote_free(struct knote *kn) 2279 { 2280 if (kn != NULL) 2281 uma_zfree(knote_zone, kn); 2282 } 2283 2284 /* 2285 * Register the kev w/ the kq specified by fd. 2286 */ 2287 int 2288 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2289 { 2290 struct kqueue *kq; 2291 struct file *fp; 2292 cap_rights_t rights; 2293 int error; 2294 2295 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2296 if (error != 0) 2297 return (error); 2298 if ((error = kqueue_acquire(fp, &kq)) != 0) 2299 goto noacquire; 2300 2301 error = kqueue_register(kq, kev, td, waitok); 2302 2303 kqueue_release(kq, 0); 2304 2305 noacquire: 2306 fdrop(fp, td); 2307 2308 return error; 2309 }
Cache object: 30643b9d584b8d853af788996dee62a0
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