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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/8.2/sys/kern/kern_event.c 206605 2010-04-14 15:33:15Z jhb $"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/proc.h> 40 #include <sys/malloc.h> 41 #include <sys/unistd.h> 42 #include <sys/file.h> 43 #include <sys/filedesc.h> 44 #include <sys/filio.h> 45 #include <sys/fcntl.h> 46 #include <sys/kthread.h> 47 #include <sys/selinfo.h> 48 #include <sys/queue.h> 49 #include <sys/event.h> 50 #include <sys/eventvar.h> 51 #include <sys/poll.h> 52 #include <sys/protosw.h> 53 #include <sys/sigio.h> 54 #include <sys/signalvar.h> 55 #include <sys/socket.h> 56 #include <sys/socketvar.h> 57 #include <sys/stat.h> 58 #include <sys/sysctl.h> 59 #include <sys/sysproto.h> 60 #include <sys/syscallsubr.h> 61 #include <sys/taskqueue.h> 62 #include <sys/uio.h> 63 #ifdef KTRACE 64 #include <sys/ktrace.h> 65 #endif 66 67 #include <vm/uma.h> 68 69 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 70 71 /* 72 * This lock is used if multiple kq locks are required. This possibly 73 * should be made into a per proc lock. 74 */ 75 static struct mtx kq_global; 76 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 77 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 78 if (!haslck) \ 79 mtx_lock(lck); \ 80 haslck = 1; \ 81 } while (0) 82 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 83 if (haslck) \ 84 mtx_unlock(lck); \ 85 haslck = 0; \ 86 } while (0) 87 88 TASKQUEUE_DEFINE_THREAD(kqueue); 89 90 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 91 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 92 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 93 struct thread *td, int waitok); 94 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 95 static void kqueue_release(struct kqueue *kq, int locked); 96 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 97 uintptr_t ident, int waitok); 98 static void kqueue_task(void *arg, int pending); 99 static int kqueue_scan(struct kqueue *kq, int maxevents, 100 struct kevent_copyops *k_ops, 101 const struct timespec *timeout, 102 struct kevent *keva, struct thread *td); 103 static void kqueue_wakeup(struct kqueue *kq); 104 static struct filterops *kqueue_fo_find(int filt); 105 static void kqueue_fo_release(int filt); 106 107 static fo_rdwr_t kqueue_read; 108 static fo_rdwr_t kqueue_write; 109 static fo_truncate_t kqueue_truncate; 110 static fo_ioctl_t kqueue_ioctl; 111 static fo_poll_t kqueue_poll; 112 static fo_kqfilter_t kqueue_kqfilter; 113 static fo_stat_t kqueue_stat; 114 static fo_close_t kqueue_close; 115 116 static struct fileops kqueueops = { 117 .fo_read = kqueue_read, 118 .fo_write = kqueue_write, 119 .fo_truncate = kqueue_truncate, 120 .fo_ioctl = kqueue_ioctl, 121 .fo_poll = kqueue_poll, 122 .fo_kqfilter = kqueue_kqfilter, 123 .fo_stat = kqueue_stat, 124 .fo_close = kqueue_close, 125 }; 126 127 static int knote_attach(struct knote *kn, struct kqueue *kq); 128 static void knote_drop(struct knote *kn, struct thread *td); 129 static void knote_enqueue(struct knote *kn); 130 static void knote_dequeue(struct knote *kn); 131 static void knote_init(void); 132 static struct knote *knote_alloc(int waitok); 133 static void knote_free(struct knote *kn); 134 135 static void filt_kqdetach(struct knote *kn); 136 static int filt_kqueue(struct knote *kn, long hint); 137 static int filt_procattach(struct knote *kn); 138 static void filt_procdetach(struct knote *kn); 139 static int filt_proc(struct knote *kn, long hint); 140 static int filt_fileattach(struct knote *kn); 141 static void filt_timerexpire(void *knx); 142 static int filt_timerattach(struct knote *kn); 143 static void filt_timerdetach(struct knote *kn); 144 static int filt_timer(struct knote *kn, long hint); 145 static int filt_userattach(struct knote *kn); 146 static void filt_userdetach(struct knote *kn); 147 static int filt_user(struct knote *kn, long hint); 148 static void filt_usertouch(struct knote *kn, struct kevent *kev, 149 u_long type); 150 151 static struct filterops file_filtops = 152 { 1, filt_fileattach, NULL, NULL }; 153 static struct filterops kqread_filtops = 154 { 1, NULL, filt_kqdetach, filt_kqueue }; 155 /* XXX - move to kern_proc.c? */ 156 static struct filterops proc_filtops = 157 { 0, filt_procattach, filt_procdetach, filt_proc }; 158 static struct filterops timer_filtops = 159 { 0, filt_timerattach, filt_timerdetach, filt_timer }; 160 static struct filterops user_filtops = { 161 .f_attach = filt_userattach, 162 .f_detach = filt_userdetach, 163 .f_event = filt_user, 164 .f_touch = filt_usertouch, 165 }; 166 167 static uma_zone_t knote_zone; 168 static int kq_ncallouts = 0; 169 static int kq_calloutmax = (4 * 1024); 170 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 171 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 172 173 /* XXX - ensure not KN_INFLUX?? */ 174 #define KNOTE_ACTIVATE(kn, islock) do { \ 175 if ((islock)) \ 176 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 177 else \ 178 KQ_LOCK((kn)->kn_kq); \ 179 (kn)->kn_status |= KN_ACTIVE; \ 180 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 181 knote_enqueue((kn)); \ 182 if (!(islock)) \ 183 KQ_UNLOCK((kn)->kn_kq); \ 184 } while(0) 185 #define KQ_LOCK(kq) do { \ 186 mtx_lock(&(kq)->kq_lock); \ 187 } while (0) 188 #define KQ_FLUX_WAKEUP(kq) do { \ 189 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 190 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 191 wakeup((kq)); \ 192 } \ 193 } while (0) 194 #define KQ_UNLOCK_FLUX(kq) do { \ 195 KQ_FLUX_WAKEUP(kq); \ 196 mtx_unlock(&(kq)->kq_lock); \ 197 } while (0) 198 #define KQ_UNLOCK(kq) do { \ 199 mtx_unlock(&(kq)->kq_lock); \ 200 } while (0) 201 #define KQ_OWNED(kq) do { \ 202 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 203 } while (0) 204 #define KQ_NOTOWNED(kq) do { \ 205 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 206 } while (0) 207 #define KN_LIST_LOCK(kn) do { \ 208 if (kn->kn_knlist != NULL) \ 209 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 210 } while (0) 211 #define KN_LIST_UNLOCK(kn) do { \ 212 if (kn->kn_knlist != NULL) \ 213 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 214 } while (0) 215 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 216 if (islocked) \ 217 KNL_ASSERT_LOCKED(knl); \ 218 else \ 219 KNL_ASSERT_UNLOCKED(knl); \ 220 } while (0) 221 #ifdef INVARIANTS 222 #define KNL_ASSERT_LOCKED(knl) do { \ 223 knl->kl_assert_locked((knl)->kl_lockarg); \ 224 } while (0) 225 #define KNL_ASSERT_UNLOCKED(knl) do { \ 226 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 227 } while (0) 228 #else /* !INVARIANTS */ 229 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 230 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 231 #endif /* INVARIANTS */ 232 233 #define KN_HASHSIZE 64 /* XXX should be tunable */ 234 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 235 236 static int 237 filt_nullattach(struct knote *kn) 238 { 239 240 return (ENXIO); 241 }; 242 243 struct filterops null_filtops = 244 { 0, filt_nullattach, NULL, NULL }; 245 246 /* XXX - make SYSINIT to add these, and move into respective modules. */ 247 extern struct filterops sig_filtops; 248 extern struct filterops fs_filtops; 249 250 /* 251 * Table for for all system-defined filters. 252 */ 253 static struct mtx filterops_lock; 254 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 255 MTX_DEF); 256 static struct { 257 struct filterops *for_fop; 258 int for_refcnt; 259 } sysfilt_ops[EVFILT_SYSCOUNT] = { 260 { &file_filtops }, /* EVFILT_READ */ 261 { &file_filtops }, /* EVFILT_WRITE */ 262 { &null_filtops }, /* EVFILT_AIO */ 263 { &file_filtops }, /* EVFILT_VNODE */ 264 { &proc_filtops }, /* EVFILT_PROC */ 265 { &sig_filtops }, /* EVFILT_SIGNAL */ 266 { &timer_filtops }, /* EVFILT_TIMER */ 267 { &null_filtops }, /* former EVFILT_NETDEV */ 268 { &fs_filtops }, /* EVFILT_FS */ 269 { &null_filtops }, /* EVFILT_LIO */ 270 { &user_filtops }, /* EVFILT_USER */ 271 }; 272 273 /* 274 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 275 * method. 276 */ 277 static int 278 filt_fileattach(struct knote *kn) 279 { 280 281 return (fo_kqfilter(kn->kn_fp, kn)); 282 } 283 284 /*ARGSUSED*/ 285 static int 286 kqueue_kqfilter(struct file *fp, struct knote *kn) 287 { 288 struct kqueue *kq = kn->kn_fp->f_data; 289 290 if (kn->kn_filter != EVFILT_READ) 291 return (EINVAL); 292 293 kn->kn_status |= KN_KQUEUE; 294 kn->kn_fop = &kqread_filtops; 295 knlist_add(&kq->kq_sel.si_note, kn, 0); 296 297 return (0); 298 } 299 300 static void 301 filt_kqdetach(struct knote *kn) 302 { 303 struct kqueue *kq = kn->kn_fp->f_data; 304 305 knlist_remove(&kq->kq_sel.si_note, kn, 0); 306 } 307 308 /*ARGSUSED*/ 309 static int 310 filt_kqueue(struct knote *kn, long hint) 311 { 312 struct kqueue *kq = kn->kn_fp->f_data; 313 314 kn->kn_data = kq->kq_count; 315 return (kn->kn_data > 0); 316 } 317 318 /* XXX - move to kern_proc.c? */ 319 static int 320 filt_procattach(struct knote *kn) 321 { 322 struct proc *p; 323 int immediate; 324 int error; 325 326 immediate = 0; 327 p = pfind(kn->kn_id); 328 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 329 p = zpfind(kn->kn_id); 330 immediate = 1; 331 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 332 immediate = 1; 333 } 334 335 if (p == NULL) 336 return (ESRCH); 337 if ((error = p_cansee(curthread, p))) { 338 PROC_UNLOCK(p); 339 return (error); 340 } 341 342 kn->kn_ptr.p_proc = p; 343 kn->kn_flags |= EV_CLEAR; /* automatically set */ 344 345 /* 346 * internal flag indicating registration done by kernel 347 */ 348 if (kn->kn_flags & EV_FLAG1) { 349 kn->kn_data = kn->kn_sdata; /* ppid */ 350 kn->kn_fflags = NOTE_CHILD; 351 kn->kn_flags &= ~EV_FLAG1; 352 } 353 354 if (immediate == 0) 355 knlist_add(&p->p_klist, kn, 1); 356 357 /* 358 * Immediately activate any exit notes if the target process is a 359 * zombie. This is necessary to handle the case where the target 360 * process, e.g. a child, dies before the kevent is registered. 361 */ 362 if (immediate && filt_proc(kn, NOTE_EXIT)) 363 KNOTE_ACTIVATE(kn, 0); 364 365 PROC_UNLOCK(p); 366 367 return (0); 368 } 369 370 /* 371 * The knote may be attached to a different process, which may exit, 372 * leaving nothing for the knote to be attached to. So when the process 373 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 374 * it will be deleted when read out. However, as part of the knote deletion, 375 * this routine is called, so a check is needed to avoid actually performing 376 * a detach, because the original process does not exist any more. 377 */ 378 /* XXX - move to kern_proc.c? */ 379 static void 380 filt_procdetach(struct knote *kn) 381 { 382 struct proc *p; 383 384 p = kn->kn_ptr.p_proc; 385 knlist_remove(&p->p_klist, kn, 0); 386 kn->kn_ptr.p_proc = NULL; 387 } 388 389 /* XXX - move to kern_proc.c? */ 390 static int 391 filt_proc(struct knote *kn, long hint) 392 { 393 struct proc *p = kn->kn_ptr.p_proc; 394 u_int event; 395 396 /* 397 * mask off extra data 398 */ 399 event = (u_int)hint & NOTE_PCTRLMASK; 400 401 /* 402 * if the user is interested in this event, record it. 403 */ 404 if (kn->kn_sfflags & event) 405 kn->kn_fflags |= event; 406 407 /* 408 * process is gone, so flag the event as finished. 409 */ 410 if (event == NOTE_EXIT) { 411 if (!(kn->kn_status & KN_DETACHED)) 412 knlist_remove_inevent(&p->p_klist, kn); 413 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 414 kn->kn_data = p->p_xstat; 415 kn->kn_ptr.p_proc = NULL; 416 return (1); 417 } 418 419 return (kn->kn_fflags != 0); 420 } 421 422 /* 423 * Called when the process forked. It mostly does the same as the 424 * knote(), activating all knotes registered to be activated when the 425 * process forked. Additionally, for each knote attached to the 426 * parent, check whether user wants to track the new process. If so 427 * attach a new knote to it, and immediately report an event with the 428 * child's pid. 429 */ 430 void 431 knote_fork(struct knlist *list, int pid) 432 { 433 struct kqueue *kq; 434 struct knote *kn; 435 struct kevent kev; 436 int error; 437 438 if (list == NULL) 439 return; 440 list->kl_lock(list->kl_lockarg); 441 442 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 443 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 444 continue; 445 kq = kn->kn_kq; 446 KQ_LOCK(kq); 447 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 448 KQ_UNLOCK(kq); 449 continue; 450 } 451 452 /* 453 * The same as knote(), activate the event. 454 */ 455 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 456 kn->kn_status |= KN_HASKQLOCK; 457 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid)) 458 KNOTE_ACTIVATE(kn, 1); 459 kn->kn_status &= ~KN_HASKQLOCK; 460 KQ_UNLOCK(kq); 461 continue; 462 } 463 464 /* 465 * The NOTE_TRACK case. In addition to the activation 466 * of the event, we need to register new event to 467 * track the child. Drop the locks in preparation for 468 * the call to kqueue_register(). 469 */ 470 kn->kn_status |= KN_INFLUX; 471 KQ_UNLOCK(kq); 472 list->kl_unlock(list->kl_lockarg); 473 474 /* 475 * Activate existing knote and register a knote with 476 * new process. 477 */ 478 kev.ident = pid; 479 kev.filter = kn->kn_filter; 480 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 481 kev.fflags = kn->kn_sfflags; 482 kev.data = kn->kn_id; /* parent */ 483 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 484 error = kqueue_register(kq, &kev, NULL, 0); 485 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid)) 486 KNOTE_ACTIVATE(kn, 0); 487 if (error) 488 kn->kn_fflags |= NOTE_TRACKERR; 489 KQ_LOCK(kq); 490 kn->kn_status &= ~KN_INFLUX; 491 KQ_UNLOCK_FLUX(kq); 492 list->kl_lock(list->kl_lockarg); 493 } 494 list->kl_unlock(list->kl_lockarg); 495 } 496 497 static int 498 timertoticks(intptr_t data) 499 { 500 struct timeval tv; 501 int tticks; 502 503 tv.tv_sec = data / 1000; 504 tv.tv_usec = (data % 1000) * 1000; 505 tticks = tvtohz(&tv); 506 507 return tticks; 508 } 509 510 /* XXX - move to kern_timeout.c? */ 511 static void 512 filt_timerexpire(void *knx) 513 { 514 struct knote *kn = knx; 515 struct callout *calloutp; 516 517 kn->kn_data++; 518 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 519 520 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 521 calloutp = (struct callout *)kn->kn_hook; 522 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata), 523 filt_timerexpire, kn); 524 } 525 } 526 527 /* 528 * data contains amount of time to sleep, in milliseconds 529 */ 530 /* XXX - move to kern_timeout.c? */ 531 static int 532 filt_timerattach(struct knote *kn) 533 { 534 struct callout *calloutp; 535 536 atomic_add_int(&kq_ncallouts, 1); 537 538 if (kq_ncallouts >= kq_calloutmax) { 539 atomic_add_int(&kq_ncallouts, -1); 540 return (ENOMEM); 541 } 542 543 kn->kn_flags |= EV_CLEAR; /* automatically set */ 544 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */ 545 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 546 callout_init(calloutp, CALLOUT_MPSAFE); 547 kn->kn_hook = calloutp; 548 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata), 549 filt_timerexpire, kn); 550 551 return (0); 552 } 553 554 /* XXX - move to kern_timeout.c? */ 555 static void 556 filt_timerdetach(struct knote *kn) 557 { 558 struct callout *calloutp; 559 560 calloutp = (struct callout *)kn->kn_hook; 561 callout_drain(calloutp); 562 free(calloutp, M_KQUEUE); 563 atomic_add_int(&kq_ncallouts, -1); 564 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */ 565 } 566 567 /* XXX - move to kern_timeout.c? */ 568 static int 569 filt_timer(struct knote *kn, long hint) 570 { 571 572 return (kn->kn_data != 0); 573 } 574 575 static int 576 filt_userattach(struct knote *kn) 577 { 578 579 /* 580 * EVFILT_USER knotes are not attached to anything in the kernel. 581 */ 582 kn->kn_hook = NULL; 583 if (kn->kn_fflags & NOTE_TRIGGER) 584 kn->kn_hookid = 1; 585 else 586 kn->kn_hookid = 0; 587 return (0); 588 } 589 590 static void 591 filt_userdetach(__unused struct knote *kn) 592 { 593 594 /* 595 * EVFILT_USER knotes are not attached to anything in the kernel. 596 */ 597 } 598 599 static int 600 filt_user(struct knote *kn, __unused long hint) 601 { 602 603 return (kn->kn_hookid); 604 } 605 606 static void 607 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 608 { 609 u_int ffctrl; 610 611 switch (type) { 612 case EVENT_REGISTER: 613 if (kev->fflags & NOTE_TRIGGER) 614 kn->kn_hookid = 1; 615 616 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 617 kev->fflags &= NOTE_FFLAGSMASK; 618 switch (ffctrl) { 619 case NOTE_FFNOP: 620 break; 621 622 case NOTE_FFAND: 623 kn->kn_sfflags &= kev->fflags; 624 break; 625 626 case NOTE_FFOR: 627 kn->kn_sfflags |= kev->fflags; 628 break; 629 630 case NOTE_FFCOPY: 631 kn->kn_sfflags = kev->fflags; 632 break; 633 634 default: 635 /* XXX Return error? */ 636 break; 637 } 638 kn->kn_sdata = kev->data; 639 if (kev->flags & EV_CLEAR) { 640 kn->kn_hookid = 0; 641 kn->kn_data = 0; 642 kn->kn_fflags = 0; 643 } 644 break; 645 646 case EVENT_PROCESS: 647 *kev = kn->kn_kevent; 648 kev->fflags = kn->kn_sfflags; 649 kev->data = kn->kn_sdata; 650 if (kn->kn_flags & EV_CLEAR) { 651 kn->kn_hookid = 0; 652 kn->kn_data = 0; 653 kn->kn_fflags = 0; 654 } 655 break; 656 657 default: 658 panic("filt_usertouch() - invalid type (%ld)", type); 659 break; 660 } 661 } 662 663 int 664 kqueue(struct thread *td, struct kqueue_args *uap) 665 { 666 struct filedesc *fdp; 667 struct kqueue *kq; 668 struct file *fp; 669 int fd, error; 670 671 fdp = td->td_proc->p_fd; 672 error = falloc(td, &fp, &fd); 673 if (error) 674 goto done2; 675 676 /* An extra reference on `nfp' has been held for us by falloc(). */ 677 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 678 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 679 TAILQ_INIT(&kq->kq_head); 680 kq->kq_fdp = fdp; 681 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 682 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 683 684 FILEDESC_XLOCK(fdp); 685 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 686 FILEDESC_XUNLOCK(fdp); 687 688 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 689 fdrop(fp, td); 690 691 td->td_retval[0] = fd; 692 done2: 693 return (error); 694 } 695 696 #ifndef _SYS_SYSPROTO_H_ 697 struct kevent_args { 698 int fd; 699 const struct kevent *changelist; 700 int nchanges; 701 struct kevent *eventlist; 702 int nevents; 703 const struct timespec *timeout; 704 }; 705 #endif 706 int 707 kevent(struct thread *td, struct kevent_args *uap) 708 { 709 struct timespec ts, *tsp; 710 struct kevent_copyops k_ops = { uap, 711 kevent_copyout, 712 kevent_copyin}; 713 int error; 714 #ifdef KTRACE 715 struct uio ktruio; 716 struct iovec ktriov; 717 struct uio *ktruioin = NULL; 718 struct uio *ktruioout = NULL; 719 #endif 720 721 if (uap->timeout != NULL) { 722 error = copyin(uap->timeout, &ts, sizeof(ts)); 723 if (error) 724 return (error); 725 tsp = &ts; 726 } else 727 tsp = NULL; 728 729 #ifdef KTRACE 730 if (KTRPOINT(td, KTR_GENIO)) { 731 ktriov.iov_base = uap->changelist; 732 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 733 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 734 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 735 .uio_td = td }; 736 ktruioin = cloneuio(&ktruio); 737 ktriov.iov_base = uap->eventlist; 738 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 739 ktruioout = cloneuio(&ktruio); 740 } 741 #endif 742 743 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 744 &k_ops, tsp); 745 746 #ifdef KTRACE 747 if (ktruioin != NULL) { 748 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 749 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 750 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 751 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 752 } 753 #endif 754 755 return (error); 756 } 757 758 /* 759 * Copy 'count' items into the destination list pointed to by uap->eventlist. 760 */ 761 static int 762 kevent_copyout(void *arg, struct kevent *kevp, int count) 763 { 764 struct kevent_args *uap; 765 int error; 766 767 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 768 uap = (struct kevent_args *)arg; 769 770 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 771 if (error == 0) 772 uap->eventlist += count; 773 return (error); 774 } 775 776 /* 777 * Copy 'count' items from the list pointed to by uap->changelist. 778 */ 779 static int 780 kevent_copyin(void *arg, struct kevent *kevp, int count) 781 { 782 struct kevent_args *uap; 783 int error; 784 785 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 786 uap = (struct kevent_args *)arg; 787 788 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 789 if (error == 0) 790 uap->changelist += count; 791 return (error); 792 } 793 794 int 795 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 796 struct kevent_copyops *k_ops, const struct timespec *timeout) 797 { 798 struct kevent keva[KQ_NEVENTS]; 799 struct kevent *kevp, *changes; 800 struct kqueue *kq; 801 struct file *fp; 802 int i, n, nerrors, error; 803 804 if ((error = fget(td, fd, &fp)) != 0) 805 return (error); 806 if ((error = kqueue_acquire(fp, &kq)) != 0) 807 goto done_norel; 808 809 nerrors = 0; 810 811 while (nchanges > 0) { 812 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 813 error = k_ops->k_copyin(k_ops->arg, keva, n); 814 if (error) 815 goto done; 816 changes = keva; 817 for (i = 0; i < n; i++) { 818 kevp = &changes[i]; 819 if (!kevp->filter) 820 continue; 821 kevp->flags &= ~EV_SYSFLAGS; 822 error = kqueue_register(kq, kevp, td, 1); 823 if (error || (kevp->flags & EV_RECEIPT)) { 824 if (nevents != 0) { 825 kevp->flags = EV_ERROR; 826 kevp->data = error; 827 (void) k_ops->k_copyout(k_ops->arg, 828 kevp, 1); 829 nevents--; 830 nerrors++; 831 } else { 832 goto done; 833 } 834 } 835 } 836 nchanges -= n; 837 } 838 if (nerrors) { 839 td->td_retval[0] = nerrors; 840 error = 0; 841 goto done; 842 } 843 844 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 845 done: 846 kqueue_release(kq, 0); 847 done_norel: 848 fdrop(fp, td); 849 return (error); 850 } 851 852 int 853 kqueue_add_filteropts(int filt, struct filterops *filtops) 854 { 855 int error; 856 857 error = 0; 858 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 859 printf( 860 "trying to add a filterop that is out of range: %d is beyond %d\n", 861 ~filt, EVFILT_SYSCOUNT); 862 return EINVAL; 863 } 864 mtx_lock(&filterops_lock); 865 if (sysfilt_ops[~filt].for_fop != &null_filtops && 866 sysfilt_ops[~filt].for_fop != NULL) 867 error = EEXIST; 868 else { 869 sysfilt_ops[~filt].for_fop = filtops; 870 sysfilt_ops[~filt].for_refcnt = 0; 871 } 872 mtx_unlock(&filterops_lock); 873 874 return (error); 875 } 876 877 int 878 kqueue_del_filteropts(int filt) 879 { 880 int error; 881 882 error = 0; 883 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 884 return EINVAL; 885 886 mtx_lock(&filterops_lock); 887 if (sysfilt_ops[~filt].for_fop == &null_filtops || 888 sysfilt_ops[~filt].for_fop == NULL) 889 error = EINVAL; 890 else if (sysfilt_ops[~filt].for_refcnt != 0) 891 error = EBUSY; 892 else { 893 sysfilt_ops[~filt].for_fop = &null_filtops; 894 sysfilt_ops[~filt].for_refcnt = 0; 895 } 896 mtx_unlock(&filterops_lock); 897 898 return error; 899 } 900 901 static struct filterops * 902 kqueue_fo_find(int filt) 903 { 904 905 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 906 return NULL; 907 908 mtx_lock(&filterops_lock); 909 sysfilt_ops[~filt].for_refcnt++; 910 if (sysfilt_ops[~filt].for_fop == NULL) 911 sysfilt_ops[~filt].for_fop = &null_filtops; 912 mtx_unlock(&filterops_lock); 913 914 return sysfilt_ops[~filt].for_fop; 915 } 916 917 static void 918 kqueue_fo_release(int filt) 919 { 920 921 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 922 return; 923 924 mtx_lock(&filterops_lock); 925 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 926 ("filter object refcount not valid on release")); 927 sysfilt_ops[~filt].for_refcnt--; 928 mtx_unlock(&filterops_lock); 929 } 930 931 /* 932 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 933 * influence if memory allocation should wait. Make sure it is 0 if you 934 * hold any mutexes. 935 */ 936 static int 937 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 938 { 939 struct filterops *fops; 940 struct file *fp; 941 struct knote *kn, *tkn; 942 int error, filt, event; 943 int haskqglobal; 944 945 fp = NULL; 946 kn = NULL; 947 error = 0; 948 haskqglobal = 0; 949 950 filt = kev->filter; 951 fops = kqueue_fo_find(filt); 952 if (fops == NULL) 953 return EINVAL; 954 955 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 956 957 findkn: 958 if (fops->f_isfd) { 959 KASSERT(td != NULL, ("td is NULL")); 960 error = fget(td, kev->ident, &fp); 961 if (error) 962 goto done; 963 964 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 965 kev->ident, 0) != 0) { 966 /* try again */ 967 fdrop(fp, td); 968 fp = NULL; 969 error = kqueue_expand(kq, fops, kev->ident, waitok); 970 if (error) 971 goto done; 972 goto findkn; 973 } 974 975 if (fp->f_type == DTYPE_KQUEUE) { 976 /* 977 * if we add some inteligence about what we are doing, 978 * we should be able to support events on ourselves. 979 * We need to know when we are doing this to prevent 980 * getting both the knlist lock and the kq lock since 981 * they are the same thing. 982 */ 983 if (fp->f_data == kq) { 984 error = EINVAL; 985 goto done; 986 } 987 988 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 989 } 990 991 KQ_LOCK(kq); 992 if (kev->ident < kq->kq_knlistsize) { 993 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 994 if (kev->filter == kn->kn_filter) 995 break; 996 } 997 } else { 998 if ((kev->flags & EV_ADD) == EV_ADD) 999 kqueue_expand(kq, fops, kev->ident, waitok); 1000 1001 KQ_LOCK(kq); 1002 if (kq->kq_knhashmask != 0) { 1003 struct klist *list; 1004 1005 list = &kq->kq_knhash[ 1006 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1007 SLIST_FOREACH(kn, list, kn_link) 1008 if (kev->ident == kn->kn_id && 1009 kev->filter == kn->kn_filter) 1010 break; 1011 } 1012 } 1013 1014 /* knote is in the process of changing, wait for it to stablize. */ 1015 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1016 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1017 kq->kq_state |= KQ_FLUXWAIT; 1018 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1019 if (fp != NULL) { 1020 fdrop(fp, td); 1021 fp = NULL; 1022 } 1023 goto findkn; 1024 } 1025 1026 /* 1027 * kn now contains the matching knote, or NULL if no match 1028 */ 1029 if (kn == NULL) { 1030 if (kev->flags & EV_ADD) { 1031 kn = tkn; 1032 tkn = NULL; 1033 if (kn == NULL) { 1034 KQ_UNLOCK(kq); 1035 error = ENOMEM; 1036 goto done; 1037 } 1038 kn->kn_fp = fp; 1039 kn->kn_kq = kq; 1040 kn->kn_fop = fops; 1041 /* 1042 * apply reference counts to knote structure, and 1043 * do not release it at the end of this routine. 1044 */ 1045 fops = NULL; 1046 fp = NULL; 1047 1048 kn->kn_sfflags = kev->fflags; 1049 kn->kn_sdata = kev->data; 1050 kev->fflags = 0; 1051 kev->data = 0; 1052 kn->kn_kevent = *kev; 1053 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1054 EV_ENABLE | EV_DISABLE); 1055 kn->kn_status = KN_INFLUX|KN_DETACHED; 1056 1057 error = knote_attach(kn, kq); 1058 KQ_UNLOCK(kq); 1059 if (error != 0) { 1060 tkn = kn; 1061 goto done; 1062 } 1063 1064 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1065 knote_drop(kn, td); 1066 goto done; 1067 } 1068 KN_LIST_LOCK(kn); 1069 goto done_ev_add; 1070 } else { 1071 /* No matching knote and the EV_ADD flag is not set. */ 1072 KQ_UNLOCK(kq); 1073 error = ENOENT; 1074 goto done; 1075 } 1076 } 1077 1078 if (kev->flags & EV_DELETE) { 1079 kn->kn_status |= KN_INFLUX; 1080 KQ_UNLOCK(kq); 1081 if (!(kn->kn_status & KN_DETACHED)) 1082 kn->kn_fop->f_detach(kn); 1083 knote_drop(kn, td); 1084 goto done; 1085 } 1086 1087 /* 1088 * The user may change some filter values after the initial EV_ADD, 1089 * but doing so will not reset any filter which has already been 1090 * triggered. 1091 */ 1092 kn->kn_status |= KN_INFLUX; 1093 KQ_UNLOCK(kq); 1094 KN_LIST_LOCK(kn); 1095 kn->kn_kevent.udata = kev->udata; 1096 if (!fops->f_isfd && fops->f_touch != NULL) { 1097 fops->f_touch(kn, kev, EVENT_REGISTER); 1098 } else { 1099 kn->kn_sfflags = kev->fflags; 1100 kn->kn_sdata = kev->data; 1101 } 1102 1103 /* 1104 * We can get here with kn->kn_knlist == NULL. This can happen when 1105 * the initial attach event decides that the event is "completed" 1106 * already. i.e. filt_procattach is called on a zombie process. It 1107 * will call filt_proc which will remove it from the list, and NULL 1108 * kn_knlist. 1109 */ 1110 done_ev_add: 1111 event = kn->kn_fop->f_event(kn, 0); 1112 KQ_LOCK(kq); 1113 if (event) 1114 KNOTE_ACTIVATE(kn, 1); 1115 kn->kn_status &= ~KN_INFLUX; 1116 KN_LIST_UNLOCK(kn); 1117 1118 if ((kev->flags & EV_DISABLE) && 1119 ((kn->kn_status & KN_DISABLED) == 0)) { 1120 kn->kn_status |= KN_DISABLED; 1121 } 1122 1123 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1124 kn->kn_status &= ~KN_DISABLED; 1125 if ((kn->kn_status & KN_ACTIVE) && 1126 ((kn->kn_status & KN_QUEUED) == 0)) 1127 knote_enqueue(kn); 1128 } 1129 KQ_UNLOCK_FLUX(kq); 1130 1131 done: 1132 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1133 if (fp != NULL) 1134 fdrop(fp, td); 1135 if (tkn != NULL) 1136 knote_free(tkn); 1137 if (fops != NULL) 1138 kqueue_fo_release(filt); 1139 return (error); 1140 } 1141 1142 static int 1143 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1144 { 1145 int error; 1146 struct kqueue *kq; 1147 1148 error = 0; 1149 1150 kq = fp->f_data; 1151 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1152 return (EBADF); 1153 *kqp = kq; 1154 KQ_LOCK(kq); 1155 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1156 KQ_UNLOCK(kq); 1157 return (EBADF); 1158 } 1159 kq->kq_refcnt++; 1160 KQ_UNLOCK(kq); 1161 1162 return error; 1163 } 1164 1165 static void 1166 kqueue_release(struct kqueue *kq, int locked) 1167 { 1168 if (locked) 1169 KQ_OWNED(kq); 1170 else 1171 KQ_LOCK(kq); 1172 kq->kq_refcnt--; 1173 if (kq->kq_refcnt == 1) 1174 wakeup(&kq->kq_refcnt); 1175 if (!locked) 1176 KQ_UNLOCK(kq); 1177 } 1178 1179 static void 1180 kqueue_schedtask(struct kqueue *kq) 1181 { 1182 1183 KQ_OWNED(kq); 1184 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1185 ("scheduling kqueue task while draining")); 1186 1187 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1188 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1189 kq->kq_state |= KQ_TASKSCHED; 1190 } 1191 } 1192 1193 /* 1194 * Expand the kq to make sure we have storage for fops/ident pair. 1195 * 1196 * Return 0 on success (or no work necessary), return errno on failure. 1197 * 1198 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1199 * If kqueue_register is called from a non-fd context, there usually/should 1200 * be no locks held. 1201 */ 1202 static int 1203 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1204 int waitok) 1205 { 1206 struct klist *list, *tmp_knhash, *to_free; 1207 u_long tmp_knhashmask; 1208 int size; 1209 int fd; 1210 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1211 1212 KQ_NOTOWNED(kq); 1213 1214 to_free = NULL; 1215 if (fops->f_isfd) { 1216 fd = ident; 1217 if (kq->kq_knlistsize <= fd) { 1218 size = kq->kq_knlistsize; 1219 while (size <= fd) 1220 size += KQEXTENT; 1221 list = malloc(size * sizeof list, M_KQUEUE, mflag); 1222 if (list == NULL) 1223 return ENOMEM; 1224 KQ_LOCK(kq); 1225 if (kq->kq_knlistsize > fd) { 1226 to_free = list; 1227 list = NULL; 1228 } else { 1229 if (kq->kq_knlist != NULL) { 1230 bcopy(kq->kq_knlist, list, 1231 kq->kq_knlistsize * sizeof list); 1232 to_free = kq->kq_knlist; 1233 kq->kq_knlist = NULL; 1234 } 1235 bzero((caddr_t)list + 1236 kq->kq_knlistsize * sizeof list, 1237 (size - kq->kq_knlistsize) * sizeof list); 1238 kq->kq_knlistsize = size; 1239 kq->kq_knlist = list; 1240 } 1241 KQ_UNLOCK(kq); 1242 } 1243 } else { 1244 if (kq->kq_knhashmask == 0) { 1245 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1246 &tmp_knhashmask); 1247 if (tmp_knhash == NULL) 1248 return ENOMEM; 1249 KQ_LOCK(kq); 1250 if (kq->kq_knhashmask == 0) { 1251 kq->kq_knhash = tmp_knhash; 1252 kq->kq_knhashmask = tmp_knhashmask; 1253 } else { 1254 to_free = tmp_knhash; 1255 } 1256 KQ_UNLOCK(kq); 1257 } 1258 } 1259 free(to_free, M_KQUEUE); 1260 1261 KQ_NOTOWNED(kq); 1262 return 0; 1263 } 1264 1265 static void 1266 kqueue_task(void *arg, int pending) 1267 { 1268 struct kqueue *kq; 1269 int haskqglobal; 1270 1271 haskqglobal = 0; 1272 kq = arg; 1273 1274 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1275 KQ_LOCK(kq); 1276 1277 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1278 1279 kq->kq_state &= ~KQ_TASKSCHED; 1280 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1281 wakeup(&kq->kq_state); 1282 } 1283 KQ_UNLOCK(kq); 1284 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1285 } 1286 1287 /* 1288 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1289 * We treat KN_MARKER knotes as if they are INFLUX. 1290 */ 1291 static int 1292 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1293 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1294 { 1295 struct kevent *kevp; 1296 struct timeval atv, rtv, ttv; 1297 struct knote *kn, *marker; 1298 int count, timeout, nkev, error, influx; 1299 int haskqglobal, touch; 1300 1301 count = maxevents; 1302 nkev = 0; 1303 error = 0; 1304 haskqglobal = 0; 1305 1306 if (maxevents == 0) 1307 goto done_nl; 1308 1309 if (tsp != NULL) { 1310 TIMESPEC_TO_TIMEVAL(&atv, tsp); 1311 if (itimerfix(&atv)) { 1312 error = EINVAL; 1313 goto done_nl; 1314 } 1315 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 1316 timeout = -1; 1317 else 1318 timeout = atv.tv_sec > 24 * 60 * 60 ? 1319 24 * 60 * 60 * hz : tvtohz(&atv); 1320 getmicrouptime(&rtv); 1321 timevaladd(&atv, &rtv); 1322 } else { 1323 atv.tv_sec = 0; 1324 atv.tv_usec = 0; 1325 timeout = 0; 1326 } 1327 marker = knote_alloc(1); 1328 if (marker == NULL) { 1329 error = ENOMEM; 1330 goto done_nl; 1331 } 1332 marker->kn_status = KN_MARKER; 1333 KQ_LOCK(kq); 1334 goto start; 1335 1336 retry: 1337 if (atv.tv_sec || atv.tv_usec) { 1338 getmicrouptime(&rtv); 1339 if (timevalcmp(&rtv, &atv, >=)) 1340 goto done; 1341 ttv = atv; 1342 timevalsub(&ttv, &rtv); 1343 timeout = ttv.tv_sec > 24 * 60 * 60 ? 1344 24 * 60 * 60 * hz : tvtohz(&ttv); 1345 } 1346 1347 start: 1348 kevp = keva; 1349 if (kq->kq_count == 0) { 1350 if (timeout < 0) { 1351 error = EWOULDBLOCK; 1352 } else { 1353 kq->kq_state |= KQ_SLEEP; 1354 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, 1355 "kqread", timeout); 1356 } 1357 if (error == 0) 1358 goto retry; 1359 /* don't restart after signals... */ 1360 if (error == ERESTART) 1361 error = EINTR; 1362 else if (error == EWOULDBLOCK) 1363 error = 0; 1364 goto done; 1365 } 1366 1367 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1368 influx = 0; 1369 while (count) { 1370 KQ_OWNED(kq); 1371 kn = TAILQ_FIRST(&kq->kq_head); 1372 1373 if ((kn->kn_status == KN_MARKER && kn != marker) || 1374 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1375 if (influx) { 1376 influx = 0; 1377 KQ_FLUX_WAKEUP(kq); 1378 } 1379 kq->kq_state |= KQ_FLUXWAIT; 1380 error = msleep(kq, &kq->kq_lock, PSOCK, 1381 "kqflxwt", 0); 1382 continue; 1383 } 1384 1385 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1386 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1387 kn->kn_status &= ~KN_QUEUED; 1388 kq->kq_count--; 1389 continue; 1390 } 1391 if (kn == marker) { 1392 KQ_FLUX_WAKEUP(kq); 1393 if (count == maxevents) 1394 goto retry; 1395 goto done; 1396 } 1397 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1398 ("KN_INFLUX set when not suppose to be")); 1399 1400 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1401 kn->kn_status &= ~KN_QUEUED; 1402 kn->kn_status |= KN_INFLUX; 1403 kq->kq_count--; 1404 KQ_UNLOCK(kq); 1405 /* 1406 * We don't need to lock the list since we've marked 1407 * it _INFLUX. 1408 */ 1409 *kevp = kn->kn_kevent; 1410 if (!(kn->kn_status & KN_DETACHED)) 1411 kn->kn_fop->f_detach(kn); 1412 knote_drop(kn, td); 1413 KQ_LOCK(kq); 1414 kn = NULL; 1415 } else { 1416 kn->kn_status |= KN_INFLUX; 1417 KQ_UNLOCK(kq); 1418 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1419 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1420 KN_LIST_LOCK(kn); 1421 if (kn->kn_fop->f_event(kn, 0) == 0) { 1422 KQ_LOCK(kq); 1423 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1424 kn->kn_status &= 1425 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1426 kq->kq_count--; 1427 KN_LIST_UNLOCK(kn); 1428 influx = 1; 1429 continue; 1430 } 1431 touch = (!kn->kn_fop->f_isfd && 1432 kn->kn_fop->f_touch != NULL); 1433 if (touch) 1434 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1435 else 1436 *kevp = kn->kn_kevent; 1437 KQ_LOCK(kq); 1438 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1439 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1440 /* 1441 * Manually clear knotes who weren't 1442 * 'touch'ed. 1443 */ 1444 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1445 kn->kn_data = 0; 1446 kn->kn_fflags = 0; 1447 } 1448 if (kn->kn_flags & EV_DISPATCH) 1449 kn->kn_status |= KN_DISABLED; 1450 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1451 kq->kq_count--; 1452 } else 1453 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1454 1455 kn->kn_status &= ~(KN_INFLUX); 1456 KN_LIST_UNLOCK(kn); 1457 influx = 1; 1458 } 1459 1460 /* we are returning a copy to the user */ 1461 kevp++; 1462 nkev++; 1463 count--; 1464 1465 if (nkev == KQ_NEVENTS) { 1466 influx = 0; 1467 KQ_UNLOCK_FLUX(kq); 1468 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1469 nkev = 0; 1470 kevp = keva; 1471 KQ_LOCK(kq); 1472 if (error) 1473 break; 1474 } 1475 } 1476 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1477 done: 1478 KQ_OWNED(kq); 1479 KQ_UNLOCK_FLUX(kq); 1480 knote_free(marker); 1481 done_nl: 1482 KQ_NOTOWNED(kq); 1483 if (nkev != 0) 1484 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1485 td->td_retval[0] = maxevents - count; 1486 return (error); 1487 } 1488 1489 /* 1490 * XXX 1491 * This could be expanded to call kqueue_scan, if desired. 1492 */ 1493 /*ARGSUSED*/ 1494 static int 1495 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1496 int flags, struct thread *td) 1497 { 1498 return (ENXIO); 1499 } 1500 1501 /*ARGSUSED*/ 1502 static int 1503 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1504 int flags, struct thread *td) 1505 { 1506 return (ENXIO); 1507 } 1508 1509 /*ARGSUSED*/ 1510 static int 1511 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1512 struct thread *td) 1513 { 1514 1515 return (EINVAL); 1516 } 1517 1518 /*ARGSUSED*/ 1519 static int 1520 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1521 struct ucred *active_cred, struct thread *td) 1522 { 1523 /* 1524 * Enabling sigio causes two major problems: 1525 * 1) infinite recursion: 1526 * Synopsys: kevent is being used to track signals and have FIOASYNC 1527 * set. On receipt of a signal this will cause a kqueue to recurse 1528 * into itself over and over. Sending the sigio causes the kqueue 1529 * to become ready, which in turn posts sigio again, forever. 1530 * Solution: this can be solved by setting a flag in the kqueue that 1531 * we have a SIGIO in progress. 1532 * 2) locking problems: 1533 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1534 * us above the proc and pgrp locks. 1535 * Solution: Post a signal using an async mechanism, being sure to 1536 * record a generation count in the delivery so that we do not deliver 1537 * a signal to the wrong process. 1538 * 1539 * Note, these two mechanisms are somewhat mutually exclusive! 1540 */ 1541 #if 0 1542 struct kqueue *kq; 1543 1544 kq = fp->f_data; 1545 switch (cmd) { 1546 case FIOASYNC: 1547 if (*(int *)data) { 1548 kq->kq_state |= KQ_ASYNC; 1549 } else { 1550 kq->kq_state &= ~KQ_ASYNC; 1551 } 1552 return (0); 1553 1554 case FIOSETOWN: 1555 return (fsetown(*(int *)data, &kq->kq_sigio)); 1556 1557 case FIOGETOWN: 1558 *(int *)data = fgetown(&kq->kq_sigio); 1559 return (0); 1560 } 1561 #endif 1562 1563 return (ENOTTY); 1564 } 1565 1566 /*ARGSUSED*/ 1567 static int 1568 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1569 struct thread *td) 1570 { 1571 struct kqueue *kq; 1572 int revents = 0; 1573 int error; 1574 1575 if ((error = kqueue_acquire(fp, &kq))) 1576 return POLLERR; 1577 1578 KQ_LOCK(kq); 1579 if (events & (POLLIN | POLLRDNORM)) { 1580 if (kq->kq_count) { 1581 revents |= events & (POLLIN | POLLRDNORM); 1582 } else { 1583 selrecord(td, &kq->kq_sel); 1584 if (SEL_WAITING(&kq->kq_sel)) 1585 kq->kq_state |= KQ_SEL; 1586 } 1587 } 1588 kqueue_release(kq, 1); 1589 KQ_UNLOCK(kq); 1590 return (revents); 1591 } 1592 1593 /*ARGSUSED*/ 1594 static int 1595 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1596 struct thread *td) 1597 { 1598 1599 bzero((void *)st, sizeof *st); 1600 /* 1601 * We no longer return kq_count because the unlocked value is useless. 1602 * If you spent all this time getting the count, why not spend your 1603 * syscall better by calling kevent? 1604 * 1605 * XXX - This is needed for libc_r. 1606 */ 1607 st->st_mode = S_IFIFO; 1608 return (0); 1609 } 1610 1611 /*ARGSUSED*/ 1612 static int 1613 kqueue_close(struct file *fp, struct thread *td) 1614 { 1615 struct kqueue *kq = fp->f_data; 1616 struct filedesc *fdp; 1617 struct knote *kn; 1618 int i; 1619 int error; 1620 1621 if ((error = kqueue_acquire(fp, &kq))) 1622 return error; 1623 1624 KQ_LOCK(kq); 1625 1626 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1627 ("kqueue already closing")); 1628 kq->kq_state |= KQ_CLOSING; 1629 if (kq->kq_refcnt > 1) 1630 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1631 1632 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1633 fdp = kq->kq_fdp; 1634 1635 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1636 ("kqueue's knlist not empty")); 1637 1638 for (i = 0; i < kq->kq_knlistsize; i++) { 1639 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1640 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1641 kq->kq_state |= KQ_FLUXWAIT; 1642 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1643 continue; 1644 } 1645 kn->kn_status |= KN_INFLUX; 1646 KQ_UNLOCK(kq); 1647 if (!(kn->kn_status & KN_DETACHED)) 1648 kn->kn_fop->f_detach(kn); 1649 knote_drop(kn, td); 1650 KQ_LOCK(kq); 1651 } 1652 } 1653 if (kq->kq_knhashmask != 0) { 1654 for (i = 0; i <= kq->kq_knhashmask; i++) { 1655 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1656 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1657 kq->kq_state |= KQ_FLUXWAIT; 1658 msleep(kq, &kq->kq_lock, PSOCK, 1659 "kqclo2", 0); 1660 continue; 1661 } 1662 kn->kn_status |= KN_INFLUX; 1663 KQ_UNLOCK(kq); 1664 if (!(kn->kn_status & KN_DETACHED)) 1665 kn->kn_fop->f_detach(kn); 1666 knote_drop(kn, td); 1667 KQ_LOCK(kq); 1668 } 1669 } 1670 } 1671 1672 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1673 kq->kq_state |= KQ_TASKDRAIN; 1674 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1675 } 1676 1677 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1678 selwakeuppri(&kq->kq_sel, PSOCK); 1679 if (!SEL_WAITING(&kq->kq_sel)) 1680 kq->kq_state &= ~KQ_SEL; 1681 } 1682 1683 KQ_UNLOCK(kq); 1684 1685 FILEDESC_XLOCK(fdp); 1686 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); 1687 FILEDESC_XUNLOCK(fdp); 1688 1689 knlist_destroy(&kq->kq_sel.si_note); 1690 mtx_destroy(&kq->kq_lock); 1691 kq->kq_fdp = NULL; 1692 1693 if (kq->kq_knhash != NULL) 1694 free(kq->kq_knhash, M_KQUEUE); 1695 if (kq->kq_knlist != NULL) 1696 free(kq->kq_knlist, M_KQUEUE); 1697 1698 funsetown(&kq->kq_sigio); 1699 free(kq, M_KQUEUE); 1700 fp->f_data = NULL; 1701 1702 return (0); 1703 } 1704 1705 static void 1706 kqueue_wakeup(struct kqueue *kq) 1707 { 1708 KQ_OWNED(kq); 1709 1710 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1711 kq->kq_state &= ~KQ_SLEEP; 1712 wakeup(kq); 1713 } 1714 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1715 selwakeuppri(&kq->kq_sel, PSOCK); 1716 if (!SEL_WAITING(&kq->kq_sel)) 1717 kq->kq_state &= ~KQ_SEL; 1718 } 1719 if (!knlist_empty(&kq->kq_sel.si_note)) 1720 kqueue_schedtask(kq); 1721 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1722 pgsigio(&kq->kq_sigio, SIGIO, 0); 1723 } 1724 } 1725 1726 /* 1727 * Walk down a list of knotes, activating them if their event has triggered. 1728 * 1729 * There is a possibility to optimize in the case of one kq watching another. 1730 * Instead of scheduling a task to wake it up, you could pass enough state 1731 * down the chain to make up the parent kqueue. Make this code functional 1732 * first. 1733 */ 1734 void 1735 knote(struct knlist *list, long hint, int lockflags) 1736 { 1737 struct kqueue *kq; 1738 struct knote *kn; 1739 int error; 1740 1741 if (list == NULL) 1742 return; 1743 1744 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1745 1746 if ((lockflags & KNF_LISTLOCKED) == 0) 1747 list->kl_lock(list->kl_lockarg); 1748 1749 /* 1750 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1751 * the kqueue scheduling, but this will introduce four 1752 * lock/unlock's for each knote to test. If we do, continue to use 1753 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1754 * only safe if you want to remove the current item, which we are 1755 * not doing. 1756 */ 1757 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1758 kq = kn->kn_kq; 1759 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1760 KQ_LOCK(kq); 1761 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1762 KQ_UNLOCK(kq); 1763 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1764 kn->kn_status |= KN_INFLUX; 1765 KQ_UNLOCK(kq); 1766 error = kn->kn_fop->f_event(kn, hint); 1767 KQ_LOCK(kq); 1768 kn->kn_status &= ~KN_INFLUX; 1769 if (error) 1770 KNOTE_ACTIVATE(kn, 1); 1771 KQ_UNLOCK_FLUX(kq); 1772 } else { 1773 kn->kn_status |= KN_HASKQLOCK; 1774 if (kn->kn_fop->f_event(kn, hint)) 1775 KNOTE_ACTIVATE(kn, 1); 1776 kn->kn_status &= ~KN_HASKQLOCK; 1777 KQ_UNLOCK(kq); 1778 } 1779 } 1780 kq = NULL; 1781 } 1782 if ((lockflags & KNF_LISTLOCKED) == 0) 1783 list->kl_unlock(list->kl_lockarg); 1784 } 1785 1786 /* 1787 * add a knote to a knlist 1788 */ 1789 void 1790 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1791 { 1792 KNL_ASSERT_LOCK(knl, islocked); 1793 KQ_NOTOWNED(kn->kn_kq); 1794 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1795 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1796 if (!islocked) 1797 knl->kl_lock(knl->kl_lockarg); 1798 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1799 if (!islocked) 1800 knl->kl_unlock(knl->kl_lockarg); 1801 KQ_LOCK(kn->kn_kq); 1802 kn->kn_knlist = knl; 1803 kn->kn_status &= ~KN_DETACHED; 1804 KQ_UNLOCK(kn->kn_kq); 1805 } 1806 1807 static void 1808 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1809 { 1810 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1811 KNL_ASSERT_LOCK(knl, knlislocked); 1812 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1813 if (!kqislocked) 1814 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1815 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1816 if (!knlislocked) 1817 knl->kl_lock(knl->kl_lockarg); 1818 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1819 kn->kn_knlist = NULL; 1820 if (!knlislocked) 1821 knl->kl_unlock(knl->kl_lockarg); 1822 if (!kqislocked) 1823 KQ_LOCK(kn->kn_kq); 1824 kn->kn_status |= KN_DETACHED; 1825 if (!kqislocked) 1826 KQ_UNLOCK(kn->kn_kq); 1827 } 1828 1829 /* 1830 * remove all knotes from a specified klist 1831 */ 1832 void 1833 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1834 { 1835 1836 knlist_remove_kq(knl, kn, islocked, 0); 1837 } 1838 1839 /* 1840 * remove knote from a specified klist while in f_event handler. 1841 */ 1842 void 1843 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1844 { 1845 1846 knlist_remove_kq(knl, kn, 1, 1847 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1848 } 1849 1850 int 1851 knlist_empty(struct knlist *knl) 1852 { 1853 KNL_ASSERT_LOCKED(knl); 1854 return SLIST_EMPTY(&knl->kl_list); 1855 } 1856 1857 static struct mtx knlist_lock; 1858 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1859 MTX_DEF); 1860 static void knlist_mtx_lock(void *arg); 1861 static void knlist_mtx_unlock(void *arg); 1862 1863 static void 1864 knlist_mtx_lock(void *arg) 1865 { 1866 mtx_lock((struct mtx *)arg); 1867 } 1868 1869 static void 1870 knlist_mtx_unlock(void *arg) 1871 { 1872 mtx_unlock((struct mtx *)arg); 1873 } 1874 1875 static void 1876 knlist_mtx_assert_locked(void *arg) 1877 { 1878 mtx_assert((struct mtx *)arg, MA_OWNED); 1879 } 1880 1881 static void 1882 knlist_mtx_assert_unlocked(void *arg) 1883 { 1884 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1885 } 1886 1887 void 1888 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 1889 void (*kl_unlock)(void *), 1890 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 1891 { 1892 1893 if (lock == NULL) 1894 knl->kl_lockarg = &knlist_lock; 1895 else 1896 knl->kl_lockarg = lock; 1897 1898 if (kl_lock == NULL) 1899 knl->kl_lock = knlist_mtx_lock; 1900 else 1901 knl->kl_lock = kl_lock; 1902 if (kl_unlock == NULL) 1903 knl->kl_unlock = knlist_mtx_unlock; 1904 else 1905 knl->kl_unlock = kl_unlock; 1906 if (kl_assert_locked == NULL) 1907 knl->kl_assert_locked = knlist_mtx_assert_locked; 1908 else 1909 knl->kl_assert_locked = kl_assert_locked; 1910 if (kl_assert_unlocked == NULL) 1911 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 1912 else 1913 knl->kl_assert_unlocked = kl_assert_unlocked; 1914 1915 SLIST_INIT(&knl->kl_list); 1916 } 1917 1918 void 1919 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 1920 { 1921 1922 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 1923 } 1924 1925 void 1926 knlist_destroy(struct knlist *knl) 1927 { 1928 1929 #ifdef INVARIANTS 1930 /* 1931 * if we run across this error, we need to find the offending 1932 * driver and have it call knlist_clear. 1933 */ 1934 if (!SLIST_EMPTY(&knl->kl_list)) 1935 printf("WARNING: destroying knlist w/ knotes on it!\n"); 1936 #endif 1937 1938 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 1939 SLIST_INIT(&knl->kl_list); 1940 } 1941 1942 /* 1943 * Even if we are locked, we may need to drop the lock to allow any influx 1944 * knotes time to "settle". 1945 */ 1946 void 1947 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 1948 { 1949 struct knote *kn, *kn2; 1950 struct kqueue *kq; 1951 1952 if (islocked) 1953 KNL_ASSERT_LOCKED(knl); 1954 else { 1955 KNL_ASSERT_UNLOCKED(knl); 1956 again: /* need to reacquire lock since we have dropped it */ 1957 knl->kl_lock(knl->kl_lockarg); 1958 } 1959 1960 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 1961 kq = kn->kn_kq; 1962 KQ_LOCK(kq); 1963 if ((kn->kn_status & KN_INFLUX)) { 1964 KQ_UNLOCK(kq); 1965 continue; 1966 } 1967 knlist_remove_kq(knl, kn, 1, 1); 1968 if (killkn) { 1969 kn->kn_status |= KN_INFLUX | KN_DETACHED; 1970 KQ_UNLOCK(kq); 1971 knote_drop(kn, td); 1972 } else { 1973 /* Make sure cleared knotes disappear soon */ 1974 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 1975 KQ_UNLOCK(kq); 1976 } 1977 kq = NULL; 1978 } 1979 1980 if (!SLIST_EMPTY(&knl->kl_list)) { 1981 /* there are still KN_INFLUX remaining */ 1982 kn = SLIST_FIRST(&knl->kl_list); 1983 kq = kn->kn_kq; 1984 KQ_LOCK(kq); 1985 KASSERT(kn->kn_status & KN_INFLUX, 1986 ("knote removed w/o list lock")); 1987 knl->kl_unlock(knl->kl_lockarg); 1988 kq->kq_state |= KQ_FLUXWAIT; 1989 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 1990 kq = NULL; 1991 goto again; 1992 } 1993 1994 if (islocked) 1995 KNL_ASSERT_LOCKED(knl); 1996 else { 1997 knl->kl_unlock(knl->kl_lockarg); 1998 KNL_ASSERT_UNLOCKED(knl); 1999 } 2000 } 2001 2002 /* 2003 * Remove all knotes referencing a specified fd must be called with FILEDESC 2004 * lock. This prevents a race where a new fd comes along and occupies the 2005 * entry and we attach a knote to the fd. 2006 */ 2007 void 2008 knote_fdclose(struct thread *td, int fd) 2009 { 2010 struct filedesc *fdp = td->td_proc->p_fd; 2011 struct kqueue *kq; 2012 struct knote *kn; 2013 int influx; 2014 2015 FILEDESC_XLOCK_ASSERT(fdp); 2016 2017 /* 2018 * We shouldn't have to worry about new kevents appearing on fd 2019 * since filedesc is locked. 2020 */ 2021 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2022 KQ_LOCK(kq); 2023 2024 again: 2025 influx = 0; 2026 while (kq->kq_knlistsize > fd && 2027 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2028 if (kn->kn_status & KN_INFLUX) { 2029 /* someone else might be waiting on our knote */ 2030 if (influx) 2031 wakeup(kq); 2032 kq->kq_state |= KQ_FLUXWAIT; 2033 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2034 goto again; 2035 } 2036 kn->kn_status |= KN_INFLUX; 2037 KQ_UNLOCK(kq); 2038 if (!(kn->kn_status & KN_DETACHED)) 2039 kn->kn_fop->f_detach(kn); 2040 knote_drop(kn, td); 2041 influx = 1; 2042 KQ_LOCK(kq); 2043 } 2044 KQ_UNLOCK_FLUX(kq); 2045 } 2046 } 2047 2048 static int 2049 knote_attach(struct knote *kn, struct kqueue *kq) 2050 { 2051 struct klist *list; 2052 2053 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2054 KQ_OWNED(kq); 2055 2056 if (kn->kn_fop->f_isfd) { 2057 if (kn->kn_id >= kq->kq_knlistsize) 2058 return ENOMEM; 2059 list = &kq->kq_knlist[kn->kn_id]; 2060 } else { 2061 if (kq->kq_knhash == NULL) 2062 return ENOMEM; 2063 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2064 } 2065 2066 SLIST_INSERT_HEAD(list, kn, kn_link); 2067 2068 return 0; 2069 } 2070 2071 /* 2072 * knote must already have been detached using the f_detach method. 2073 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2074 * to prevent other removal. 2075 */ 2076 static void 2077 knote_drop(struct knote *kn, struct thread *td) 2078 { 2079 struct kqueue *kq; 2080 struct klist *list; 2081 2082 kq = kn->kn_kq; 2083 2084 KQ_NOTOWNED(kq); 2085 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2086 ("knote_drop called without KN_INFLUX set in kn_status")); 2087 2088 KQ_LOCK(kq); 2089 if (kn->kn_fop->f_isfd) 2090 list = &kq->kq_knlist[kn->kn_id]; 2091 else 2092 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2093 2094 if (!SLIST_EMPTY(list)) 2095 SLIST_REMOVE(list, kn, knote, kn_link); 2096 if (kn->kn_status & KN_QUEUED) 2097 knote_dequeue(kn); 2098 KQ_UNLOCK_FLUX(kq); 2099 2100 if (kn->kn_fop->f_isfd) { 2101 fdrop(kn->kn_fp, td); 2102 kn->kn_fp = NULL; 2103 } 2104 kqueue_fo_release(kn->kn_kevent.filter); 2105 kn->kn_fop = NULL; 2106 knote_free(kn); 2107 } 2108 2109 static void 2110 knote_enqueue(struct knote *kn) 2111 { 2112 struct kqueue *kq = kn->kn_kq; 2113 2114 KQ_OWNED(kn->kn_kq); 2115 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2116 2117 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2118 kn->kn_status |= KN_QUEUED; 2119 kq->kq_count++; 2120 kqueue_wakeup(kq); 2121 } 2122 2123 static void 2124 knote_dequeue(struct knote *kn) 2125 { 2126 struct kqueue *kq = kn->kn_kq; 2127 2128 KQ_OWNED(kn->kn_kq); 2129 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2130 2131 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2132 kn->kn_status &= ~KN_QUEUED; 2133 kq->kq_count--; 2134 } 2135 2136 static void 2137 knote_init(void) 2138 { 2139 2140 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2141 NULL, NULL, UMA_ALIGN_PTR, 0); 2142 } 2143 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2144 2145 static struct knote * 2146 knote_alloc(int waitok) 2147 { 2148 return ((struct knote *)uma_zalloc(knote_zone, 2149 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2150 } 2151 2152 static void 2153 knote_free(struct knote *kn) 2154 { 2155 if (kn != NULL) 2156 uma_zfree(knote_zone, kn); 2157 } 2158 2159 /* 2160 * Register the kev w/ the kq specified by fd. 2161 */ 2162 int 2163 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2164 { 2165 struct kqueue *kq; 2166 struct file *fp; 2167 int error; 2168 2169 if ((error = fget(td, fd, &fp)) != 0) 2170 return (error); 2171 if ((error = kqueue_acquire(fp, &kq)) != 0) 2172 goto noacquire; 2173 2174 error = kqueue_register(kq, kev, td, waitok); 2175 2176 kqueue_release(kq, 0); 2177 2178 noacquire: 2179 fdrop(fp, td); 2180 2181 return error; 2182 }
Cache object: 204233e39cf240d6732991a325ed096f
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