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("$FreeBSD$"); 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_ptr.p_proc = NULL; 415 if (kn->kn_fflags & NOTE_EXIT) 416 kn->kn_data = p->p_xstat; 417 if (kn->kn_fflags == 0) 418 kn->kn_flags |= EV_DROP; 419 return (1); 420 } 421 422 return (kn->kn_fflags != 0); 423 } 424 425 /* 426 * Called when the process forked. It mostly does the same as the 427 * knote(), activating all knotes registered to be activated when the 428 * process forked. Additionally, for each knote attached to the 429 * parent, check whether user wants to track the new process. If so 430 * attach a new knote to it, and immediately report an event with the 431 * child's pid. 432 */ 433 void 434 knote_fork(struct knlist *list, int pid) 435 { 436 struct kqueue *kq; 437 struct knote *kn; 438 struct kevent kev; 439 int error; 440 441 if (list == NULL) 442 return; 443 list->kl_lock(list->kl_lockarg); 444 445 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 446 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 447 continue; 448 kq = kn->kn_kq; 449 KQ_LOCK(kq); 450 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 451 KQ_UNLOCK(kq); 452 continue; 453 } 454 455 /* 456 * The same as knote(), activate the event. 457 */ 458 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 459 kn->kn_status |= KN_HASKQLOCK; 460 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 461 KNOTE_ACTIVATE(kn, 1); 462 kn->kn_status &= ~KN_HASKQLOCK; 463 KQ_UNLOCK(kq); 464 continue; 465 } 466 467 /* 468 * The NOTE_TRACK case. In addition to the activation 469 * of the event, we need to register new event to 470 * track the child. Drop the locks in preparation for 471 * the call to kqueue_register(). 472 */ 473 kn->kn_status |= KN_INFLUX; 474 KQ_UNLOCK(kq); 475 list->kl_unlock(list->kl_lockarg); 476 477 /* 478 * Activate existing knote and register a knote with 479 * new process. 480 */ 481 kev.ident = pid; 482 kev.filter = kn->kn_filter; 483 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 484 kev.fflags = kn->kn_sfflags; 485 kev.data = kn->kn_id; /* parent */ 486 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 487 error = kqueue_register(kq, &kev, NULL, 0); 488 if (error) 489 kn->kn_fflags |= NOTE_TRACKERR; 490 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 491 KNOTE_ACTIVATE(kn, 0); 492 KQ_LOCK(kq); 493 kn->kn_status &= ~KN_INFLUX; 494 KQ_UNLOCK_FLUX(kq); 495 list->kl_lock(list->kl_lockarg); 496 } 497 list->kl_unlock(list->kl_lockarg); 498 } 499 500 /* 501 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 502 * interval timer support code. 503 */ 504 static int 505 timertoticks(intptr_t data) 506 { 507 struct timeval tv; 508 int tticks; 509 510 tv.tv_sec = data / 1000; 511 tv.tv_usec = (data % 1000) * 1000; 512 tticks = tvtohz(&tv); 513 514 return tticks; 515 } 516 517 static void 518 filt_timerexpire(void *knx) 519 { 520 struct knote *kn = knx; 521 struct callout *calloutp; 522 523 kn->kn_data++; 524 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 525 526 /* 527 * timertoticks() uses tvtohz() which always adds 1 to allow 528 * for the time until the next clock interrupt being strictly 529 * less than 1 clock tick. We don't want that here since we 530 * want to appear to be in sync with the clock interrupt even 531 * when we're delayed. 532 */ 533 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 534 calloutp = (struct callout *)kn->kn_hook; 535 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata) - 1, 536 filt_timerexpire, kn); 537 } 538 } 539 540 /* 541 * data contains amount of time to sleep, in milliseconds 542 */ 543 static int 544 filt_timerattach(struct knote *kn) 545 { 546 struct callout *calloutp; 547 548 atomic_add_int(&kq_ncallouts, 1); 549 550 if (kq_ncallouts >= kq_calloutmax) { 551 atomic_add_int(&kq_ncallouts, -1); 552 return (ENOMEM); 553 } 554 555 kn->kn_flags |= EV_CLEAR; /* automatically set */ 556 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */ 557 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 558 callout_init(calloutp, CALLOUT_MPSAFE); 559 kn->kn_hook = calloutp; 560 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata), 561 filt_timerexpire, kn); 562 563 return (0); 564 } 565 566 static void 567 filt_timerdetach(struct knote *kn) 568 { 569 struct callout *calloutp; 570 571 calloutp = (struct callout *)kn->kn_hook; 572 callout_drain(calloutp); 573 free(calloutp, M_KQUEUE); 574 atomic_add_int(&kq_ncallouts, -1); 575 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */ 576 } 577 578 static int 579 filt_timer(struct knote *kn, long hint) 580 { 581 582 return (kn->kn_data != 0); 583 } 584 585 static int 586 filt_userattach(struct knote *kn) 587 { 588 589 /* 590 * EVFILT_USER knotes are not attached to anything in the kernel. 591 */ 592 kn->kn_hook = NULL; 593 if (kn->kn_fflags & NOTE_TRIGGER) 594 kn->kn_hookid = 1; 595 else 596 kn->kn_hookid = 0; 597 return (0); 598 } 599 600 static void 601 filt_userdetach(__unused struct knote *kn) 602 { 603 604 /* 605 * EVFILT_USER knotes are not attached to anything in the kernel. 606 */ 607 } 608 609 static int 610 filt_user(struct knote *kn, __unused long hint) 611 { 612 613 return (kn->kn_hookid); 614 } 615 616 static void 617 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 618 { 619 u_int ffctrl; 620 621 switch (type) { 622 case EVENT_REGISTER: 623 if (kev->fflags & NOTE_TRIGGER) 624 kn->kn_hookid = 1; 625 626 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 627 kev->fflags &= NOTE_FFLAGSMASK; 628 switch (ffctrl) { 629 case NOTE_FFNOP: 630 break; 631 632 case NOTE_FFAND: 633 kn->kn_sfflags &= kev->fflags; 634 break; 635 636 case NOTE_FFOR: 637 kn->kn_sfflags |= kev->fflags; 638 break; 639 640 case NOTE_FFCOPY: 641 kn->kn_sfflags = kev->fflags; 642 break; 643 644 default: 645 /* XXX Return error? */ 646 break; 647 } 648 kn->kn_sdata = kev->data; 649 if (kev->flags & EV_CLEAR) { 650 kn->kn_hookid = 0; 651 kn->kn_data = 0; 652 kn->kn_fflags = 0; 653 } 654 break; 655 656 case EVENT_PROCESS: 657 *kev = kn->kn_kevent; 658 kev->fflags = kn->kn_sfflags; 659 kev->data = kn->kn_sdata; 660 if (kn->kn_flags & EV_CLEAR) { 661 kn->kn_hookid = 0; 662 kn->kn_data = 0; 663 kn->kn_fflags = 0; 664 } 665 break; 666 667 default: 668 panic("filt_usertouch() - invalid type (%ld)", type); 669 break; 670 } 671 } 672 673 int 674 kqueue(struct thread *td, struct kqueue_args *uap) 675 { 676 struct filedesc *fdp; 677 struct kqueue *kq; 678 struct file *fp; 679 int fd, error; 680 681 fdp = td->td_proc->p_fd; 682 error = falloc(td, &fp, &fd); 683 if (error) 684 goto done2; 685 686 /* An extra reference on `nfp' has been held for us by falloc(). */ 687 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 688 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 689 TAILQ_INIT(&kq->kq_head); 690 kq->kq_fdp = fdp; 691 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 692 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 693 694 FILEDESC_XLOCK(fdp); 695 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 696 FILEDESC_XUNLOCK(fdp); 697 698 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 699 fdrop(fp, td); 700 701 td->td_retval[0] = fd; 702 done2: 703 return (error); 704 } 705 706 #ifndef _SYS_SYSPROTO_H_ 707 struct kevent_args { 708 int fd; 709 const struct kevent *changelist; 710 int nchanges; 711 struct kevent *eventlist; 712 int nevents; 713 const struct timespec *timeout; 714 }; 715 #endif 716 int 717 kevent(struct thread *td, struct kevent_args *uap) 718 { 719 struct timespec ts, *tsp; 720 struct kevent_copyops k_ops = { uap, 721 kevent_copyout, 722 kevent_copyin}; 723 int error; 724 #ifdef KTRACE 725 struct uio ktruio; 726 struct iovec ktriov; 727 struct uio *ktruioin = NULL; 728 struct uio *ktruioout = NULL; 729 #endif 730 731 if (uap->timeout != NULL) { 732 error = copyin(uap->timeout, &ts, sizeof(ts)); 733 if (error) 734 return (error); 735 tsp = &ts; 736 } else 737 tsp = NULL; 738 739 #ifdef KTRACE 740 if (KTRPOINT(td, KTR_GENIO)) { 741 ktriov.iov_base = uap->changelist; 742 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 743 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 744 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 745 .uio_td = td }; 746 ktruioin = cloneuio(&ktruio); 747 ktriov.iov_base = uap->eventlist; 748 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 749 ktruioout = cloneuio(&ktruio); 750 } 751 #endif 752 753 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 754 &k_ops, tsp); 755 756 #ifdef KTRACE 757 if (ktruioin != NULL) { 758 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 759 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 760 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 761 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 762 } 763 #endif 764 765 return (error); 766 } 767 768 /* 769 * Copy 'count' items into the destination list pointed to by uap->eventlist. 770 */ 771 static int 772 kevent_copyout(void *arg, struct kevent *kevp, int count) 773 { 774 struct kevent_args *uap; 775 int error; 776 777 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 778 uap = (struct kevent_args *)arg; 779 780 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 781 if (error == 0) 782 uap->eventlist += count; 783 return (error); 784 } 785 786 /* 787 * Copy 'count' items from the list pointed to by uap->changelist. 788 */ 789 static int 790 kevent_copyin(void *arg, struct kevent *kevp, int count) 791 { 792 struct kevent_args *uap; 793 int error; 794 795 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 796 uap = (struct kevent_args *)arg; 797 798 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 799 if (error == 0) 800 uap->changelist += count; 801 return (error); 802 } 803 804 int 805 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 806 struct kevent_copyops *k_ops, const struct timespec *timeout) 807 { 808 struct kevent keva[KQ_NEVENTS]; 809 struct kevent *kevp, *changes; 810 struct kqueue *kq; 811 struct file *fp; 812 int i, n, nerrors, error; 813 814 if ((error = fget(td, fd, &fp)) != 0) 815 return (error); 816 if ((error = kqueue_acquire(fp, &kq)) != 0) 817 goto done_norel; 818 819 nerrors = 0; 820 821 while (nchanges > 0) { 822 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 823 error = k_ops->k_copyin(k_ops->arg, keva, n); 824 if (error) 825 goto done; 826 changes = keva; 827 for (i = 0; i < n; i++) { 828 kevp = &changes[i]; 829 if (!kevp->filter) 830 continue; 831 kevp->flags &= ~EV_SYSFLAGS; 832 error = kqueue_register(kq, kevp, td, 1); 833 if (error || (kevp->flags & EV_RECEIPT)) { 834 if (nevents != 0) { 835 kevp->flags = EV_ERROR; 836 kevp->data = error; 837 (void) k_ops->k_copyout(k_ops->arg, 838 kevp, 1); 839 nevents--; 840 nerrors++; 841 } else { 842 goto done; 843 } 844 } 845 } 846 nchanges -= n; 847 } 848 if (nerrors) { 849 td->td_retval[0] = nerrors; 850 error = 0; 851 goto done; 852 } 853 854 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 855 done: 856 kqueue_release(kq, 0); 857 done_norel: 858 fdrop(fp, td); 859 return (error); 860 } 861 862 int 863 kqueue_add_filteropts(int filt, struct filterops *filtops) 864 { 865 int error; 866 867 error = 0; 868 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 869 printf( 870 "trying to add a filterop that is out of range: %d is beyond %d\n", 871 ~filt, EVFILT_SYSCOUNT); 872 return EINVAL; 873 } 874 mtx_lock(&filterops_lock); 875 if (sysfilt_ops[~filt].for_fop != &null_filtops && 876 sysfilt_ops[~filt].for_fop != NULL) 877 error = EEXIST; 878 else { 879 sysfilt_ops[~filt].for_fop = filtops; 880 sysfilt_ops[~filt].for_refcnt = 0; 881 } 882 mtx_unlock(&filterops_lock); 883 884 return (error); 885 } 886 887 int 888 kqueue_del_filteropts(int filt) 889 { 890 int error; 891 892 error = 0; 893 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 894 return EINVAL; 895 896 mtx_lock(&filterops_lock); 897 if (sysfilt_ops[~filt].for_fop == &null_filtops || 898 sysfilt_ops[~filt].for_fop == NULL) 899 error = EINVAL; 900 else if (sysfilt_ops[~filt].for_refcnt != 0) 901 error = EBUSY; 902 else { 903 sysfilt_ops[~filt].for_fop = &null_filtops; 904 sysfilt_ops[~filt].for_refcnt = 0; 905 } 906 mtx_unlock(&filterops_lock); 907 908 return error; 909 } 910 911 static struct filterops * 912 kqueue_fo_find(int filt) 913 { 914 915 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 916 return NULL; 917 918 mtx_lock(&filterops_lock); 919 sysfilt_ops[~filt].for_refcnt++; 920 if (sysfilt_ops[~filt].for_fop == NULL) 921 sysfilt_ops[~filt].for_fop = &null_filtops; 922 mtx_unlock(&filterops_lock); 923 924 return sysfilt_ops[~filt].for_fop; 925 } 926 927 static void 928 kqueue_fo_release(int filt) 929 { 930 931 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 932 return; 933 934 mtx_lock(&filterops_lock); 935 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 936 ("filter object refcount not valid on release")); 937 sysfilt_ops[~filt].for_refcnt--; 938 mtx_unlock(&filterops_lock); 939 } 940 941 /* 942 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 943 * influence if memory allocation should wait. Make sure it is 0 if you 944 * hold any mutexes. 945 */ 946 static int 947 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 948 { 949 struct filterops *fops; 950 struct file *fp; 951 struct knote *kn, *tkn; 952 int error, filt, event; 953 int haskqglobal; 954 955 fp = NULL; 956 kn = NULL; 957 error = 0; 958 haskqglobal = 0; 959 960 filt = kev->filter; 961 fops = kqueue_fo_find(filt); 962 if (fops == NULL) 963 return EINVAL; 964 965 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 966 967 findkn: 968 if (fops->f_isfd) { 969 KASSERT(td != NULL, ("td is NULL")); 970 error = fget(td, kev->ident, &fp); 971 if (error) 972 goto done; 973 974 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 975 kev->ident, 0) != 0) { 976 /* try again */ 977 fdrop(fp, td); 978 fp = NULL; 979 error = kqueue_expand(kq, fops, kev->ident, waitok); 980 if (error) 981 goto done; 982 goto findkn; 983 } 984 985 if (fp->f_type == DTYPE_KQUEUE) { 986 /* 987 * if we add some inteligence about what we are doing, 988 * we should be able to support events on ourselves. 989 * We need to know when we are doing this to prevent 990 * getting both the knlist lock and the kq lock since 991 * they are the same thing. 992 */ 993 if (fp->f_data == kq) { 994 error = EINVAL; 995 goto done; 996 } 997 998 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 999 } 1000 1001 KQ_LOCK(kq); 1002 if (kev->ident < kq->kq_knlistsize) { 1003 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1004 if (kev->filter == kn->kn_filter) 1005 break; 1006 } 1007 } else { 1008 if ((kev->flags & EV_ADD) == EV_ADD) 1009 kqueue_expand(kq, fops, kev->ident, waitok); 1010 1011 KQ_LOCK(kq); 1012 if (kq->kq_knhashmask != 0) { 1013 struct klist *list; 1014 1015 list = &kq->kq_knhash[ 1016 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1017 SLIST_FOREACH(kn, list, kn_link) 1018 if (kev->ident == kn->kn_id && 1019 kev->filter == kn->kn_filter) 1020 break; 1021 } 1022 } 1023 1024 /* knote is in the process of changing, wait for it to stablize. */ 1025 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1026 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1027 kq->kq_state |= KQ_FLUXWAIT; 1028 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1029 if (fp != NULL) { 1030 fdrop(fp, td); 1031 fp = NULL; 1032 } 1033 goto findkn; 1034 } 1035 1036 /* 1037 * kn now contains the matching knote, or NULL if no match 1038 */ 1039 if (kn == NULL) { 1040 if (kev->flags & EV_ADD) { 1041 kn = tkn; 1042 tkn = NULL; 1043 if (kn == NULL) { 1044 KQ_UNLOCK(kq); 1045 error = ENOMEM; 1046 goto done; 1047 } 1048 kn->kn_fp = fp; 1049 kn->kn_kq = kq; 1050 kn->kn_fop = fops; 1051 /* 1052 * apply reference counts to knote structure, and 1053 * do not release it at the end of this routine. 1054 */ 1055 fops = NULL; 1056 fp = NULL; 1057 1058 kn->kn_sfflags = kev->fflags; 1059 kn->kn_sdata = kev->data; 1060 kev->fflags = 0; 1061 kev->data = 0; 1062 kn->kn_kevent = *kev; 1063 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1064 EV_ENABLE | EV_DISABLE); 1065 kn->kn_status = KN_INFLUX|KN_DETACHED; 1066 1067 error = knote_attach(kn, kq); 1068 KQ_UNLOCK(kq); 1069 if (error != 0) { 1070 tkn = kn; 1071 goto done; 1072 } 1073 1074 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1075 knote_drop(kn, td); 1076 goto done; 1077 } 1078 KN_LIST_LOCK(kn); 1079 goto done_ev_add; 1080 } else { 1081 /* No matching knote and the EV_ADD flag is not set. */ 1082 KQ_UNLOCK(kq); 1083 error = ENOENT; 1084 goto done; 1085 } 1086 } 1087 1088 if (kev->flags & EV_DELETE) { 1089 kn->kn_status |= KN_INFLUX; 1090 KQ_UNLOCK(kq); 1091 if (!(kn->kn_status & KN_DETACHED)) 1092 kn->kn_fop->f_detach(kn); 1093 knote_drop(kn, td); 1094 goto done; 1095 } 1096 1097 /* 1098 * The user may change some filter values after the initial EV_ADD, 1099 * but doing so will not reset any filter which has already been 1100 * triggered. 1101 */ 1102 kn->kn_status |= KN_INFLUX; 1103 KQ_UNLOCK(kq); 1104 KN_LIST_LOCK(kn); 1105 kn->kn_kevent.udata = kev->udata; 1106 if (!fops->f_isfd && fops->f_touch != NULL) { 1107 fops->f_touch(kn, kev, EVENT_REGISTER); 1108 } else { 1109 kn->kn_sfflags = kev->fflags; 1110 kn->kn_sdata = kev->data; 1111 } 1112 1113 /* 1114 * We can get here with kn->kn_knlist == NULL. This can happen when 1115 * the initial attach event decides that the event is "completed" 1116 * already. i.e. filt_procattach is called on a zombie process. It 1117 * will call filt_proc which will remove it from the list, and NULL 1118 * kn_knlist. 1119 */ 1120 done_ev_add: 1121 event = kn->kn_fop->f_event(kn, 0); 1122 KQ_LOCK(kq); 1123 if (event) 1124 KNOTE_ACTIVATE(kn, 1); 1125 kn->kn_status &= ~KN_INFLUX; 1126 KN_LIST_UNLOCK(kn); 1127 1128 if ((kev->flags & EV_DISABLE) && 1129 ((kn->kn_status & KN_DISABLED) == 0)) { 1130 kn->kn_status |= KN_DISABLED; 1131 } 1132 1133 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1134 kn->kn_status &= ~KN_DISABLED; 1135 if ((kn->kn_status & KN_ACTIVE) && 1136 ((kn->kn_status & KN_QUEUED) == 0)) 1137 knote_enqueue(kn); 1138 } 1139 KQ_UNLOCK_FLUX(kq); 1140 1141 done: 1142 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1143 if (fp != NULL) 1144 fdrop(fp, td); 1145 if (tkn != NULL) 1146 knote_free(tkn); 1147 if (fops != NULL) 1148 kqueue_fo_release(filt); 1149 return (error); 1150 } 1151 1152 static int 1153 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1154 { 1155 int error; 1156 struct kqueue *kq; 1157 1158 error = 0; 1159 1160 kq = fp->f_data; 1161 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1162 return (EBADF); 1163 *kqp = kq; 1164 KQ_LOCK(kq); 1165 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1166 KQ_UNLOCK(kq); 1167 return (EBADF); 1168 } 1169 kq->kq_refcnt++; 1170 KQ_UNLOCK(kq); 1171 1172 return error; 1173 } 1174 1175 static void 1176 kqueue_release(struct kqueue *kq, int locked) 1177 { 1178 if (locked) 1179 KQ_OWNED(kq); 1180 else 1181 KQ_LOCK(kq); 1182 kq->kq_refcnt--; 1183 if (kq->kq_refcnt == 1) 1184 wakeup(&kq->kq_refcnt); 1185 if (!locked) 1186 KQ_UNLOCK(kq); 1187 } 1188 1189 static void 1190 kqueue_schedtask(struct kqueue *kq) 1191 { 1192 1193 KQ_OWNED(kq); 1194 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1195 ("scheduling kqueue task while draining")); 1196 1197 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1198 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1199 kq->kq_state |= KQ_TASKSCHED; 1200 } 1201 } 1202 1203 /* 1204 * Expand the kq to make sure we have storage for fops/ident pair. 1205 * 1206 * Return 0 on success (or no work necessary), return errno on failure. 1207 * 1208 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1209 * If kqueue_register is called from a non-fd context, there usually/should 1210 * be no locks held. 1211 */ 1212 static int 1213 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1214 int waitok) 1215 { 1216 struct klist *list, *tmp_knhash, *to_free; 1217 u_long tmp_knhashmask; 1218 int size; 1219 int fd; 1220 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1221 1222 KQ_NOTOWNED(kq); 1223 1224 to_free = NULL; 1225 if (fops->f_isfd) { 1226 fd = ident; 1227 if (kq->kq_knlistsize <= fd) { 1228 size = kq->kq_knlistsize; 1229 while (size <= fd) 1230 size += KQEXTENT; 1231 list = malloc(size * sizeof list, M_KQUEUE, mflag); 1232 if (list == NULL) 1233 return ENOMEM; 1234 KQ_LOCK(kq); 1235 if (kq->kq_knlistsize > fd) { 1236 to_free = list; 1237 list = NULL; 1238 } else { 1239 if (kq->kq_knlist != NULL) { 1240 bcopy(kq->kq_knlist, list, 1241 kq->kq_knlistsize * sizeof list); 1242 to_free = kq->kq_knlist; 1243 kq->kq_knlist = NULL; 1244 } 1245 bzero((caddr_t)list + 1246 kq->kq_knlistsize * sizeof list, 1247 (size - kq->kq_knlistsize) * sizeof list); 1248 kq->kq_knlistsize = size; 1249 kq->kq_knlist = list; 1250 } 1251 KQ_UNLOCK(kq); 1252 } 1253 } else { 1254 if (kq->kq_knhashmask == 0) { 1255 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1256 &tmp_knhashmask); 1257 if (tmp_knhash == NULL) 1258 return ENOMEM; 1259 KQ_LOCK(kq); 1260 if (kq->kq_knhashmask == 0) { 1261 kq->kq_knhash = tmp_knhash; 1262 kq->kq_knhashmask = tmp_knhashmask; 1263 } else { 1264 to_free = tmp_knhash; 1265 } 1266 KQ_UNLOCK(kq); 1267 } 1268 } 1269 free(to_free, M_KQUEUE); 1270 1271 KQ_NOTOWNED(kq); 1272 return 0; 1273 } 1274 1275 static void 1276 kqueue_task(void *arg, int pending) 1277 { 1278 struct kqueue *kq; 1279 int haskqglobal; 1280 1281 haskqglobal = 0; 1282 kq = arg; 1283 1284 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1285 KQ_LOCK(kq); 1286 1287 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1288 1289 kq->kq_state &= ~KQ_TASKSCHED; 1290 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1291 wakeup(&kq->kq_state); 1292 } 1293 KQ_UNLOCK(kq); 1294 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1295 } 1296 1297 /* 1298 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1299 * We treat KN_MARKER knotes as if they are INFLUX. 1300 */ 1301 static int 1302 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1303 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1304 { 1305 struct kevent *kevp; 1306 struct timeval atv, rtv, ttv; 1307 struct knote *kn, *marker; 1308 int count, timeout, nkev, error, influx; 1309 int haskqglobal, touch; 1310 1311 count = maxevents; 1312 nkev = 0; 1313 error = 0; 1314 haskqglobal = 0; 1315 1316 if (maxevents == 0) 1317 goto done_nl; 1318 1319 if (tsp != NULL) { 1320 TIMESPEC_TO_TIMEVAL(&atv, tsp); 1321 if (itimerfix(&atv)) { 1322 error = EINVAL; 1323 goto done_nl; 1324 } 1325 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 1326 timeout = -1; 1327 else 1328 timeout = atv.tv_sec > 24 * 60 * 60 ? 1329 24 * 60 * 60 * hz : tvtohz(&atv); 1330 getmicrouptime(&rtv); 1331 timevaladd(&atv, &rtv); 1332 } else { 1333 atv.tv_sec = 0; 1334 atv.tv_usec = 0; 1335 timeout = 0; 1336 } 1337 marker = knote_alloc(1); 1338 if (marker == NULL) { 1339 error = ENOMEM; 1340 goto done_nl; 1341 } 1342 marker->kn_status = KN_MARKER; 1343 KQ_LOCK(kq); 1344 goto start; 1345 1346 retry: 1347 if (atv.tv_sec || atv.tv_usec) { 1348 getmicrouptime(&rtv); 1349 if (timevalcmp(&rtv, &atv, >=)) 1350 goto done; 1351 ttv = atv; 1352 timevalsub(&ttv, &rtv); 1353 timeout = ttv.tv_sec > 24 * 60 * 60 ? 1354 24 * 60 * 60 * hz : tvtohz(&ttv); 1355 } 1356 1357 start: 1358 kevp = keva; 1359 if (kq->kq_count == 0) { 1360 if (timeout < 0) { 1361 error = EWOULDBLOCK; 1362 } else { 1363 kq->kq_state |= KQ_SLEEP; 1364 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, 1365 "kqread", timeout); 1366 } 1367 if (error == 0) 1368 goto retry; 1369 /* don't restart after signals... */ 1370 if (error == ERESTART) 1371 error = EINTR; 1372 else if (error == EWOULDBLOCK) 1373 error = 0; 1374 goto done; 1375 } 1376 1377 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1378 influx = 0; 1379 while (count) { 1380 KQ_OWNED(kq); 1381 kn = TAILQ_FIRST(&kq->kq_head); 1382 1383 if ((kn->kn_status == KN_MARKER && kn != marker) || 1384 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1385 if (influx) { 1386 influx = 0; 1387 KQ_FLUX_WAKEUP(kq); 1388 } 1389 kq->kq_state |= KQ_FLUXWAIT; 1390 error = msleep(kq, &kq->kq_lock, PSOCK, 1391 "kqflxwt", 0); 1392 continue; 1393 } 1394 1395 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1396 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1397 kn->kn_status &= ~KN_QUEUED; 1398 kq->kq_count--; 1399 continue; 1400 } 1401 if (kn == marker) { 1402 KQ_FLUX_WAKEUP(kq); 1403 if (count == maxevents) 1404 goto retry; 1405 goto done; 1406 } 1407 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1408 ("KN_INFLUX set when not suppose to be")); 1409 1410 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1411 kn->kn_status &= ~KN_QUEUED; 1412 kn->kn_status |= KN_INFLUX; 1413 kq->kq_count--; 1414 KQ_UNLOCK(kq); 1415 /* 1416 * We don't need to lock the list since we've marked 1417 * it _INFLUX. 1418 */ 1419 if (!(kn->kn_status & KN_DETACHED)) 1420 kn->kn_fop->f_detach(kn); 1421 knote_drop(kn, td); 1422 KQ_LOCK(kq); 1423 continue; 1424 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1425 kn->kn_status &= ~KN_QUEUED; 1426 kn->kn_status |= KN_INFLUX; 1427 kq->kq_count--; 1428 KQ_UNLOCK(kq); 1429 /* 1430 * We don't need to lock the list since we've marked 1431 * it _INFLUX. 1432 */ 1433 *kevp = kn->kn_kevent; 1434 if (!(kn->kn_status & KN_DETACHED)) 1435 kn->kn_fop->f_detach(kn); 1436 knote_drop(kn, td); 1437 KQ_LOCK(kq); 1438 kn = NULL; 1439 } else { 1440 kn->kn_status |= KN_INFLUX; 1441 KQ_UNLOCK(kq); 1442 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1443 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1444 KN_LIST_LOCK(kn); 1445 if (kn->kn_fop->f_event(kn, 0) == 0) { 1446 KQ_LOCK(kq); 1447 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1448 kn->kn_status &= 1449 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1450 kq->kq_count--; 1451 KN_LIST_UNLOCK(kn); 1452 influx = 1; 1453 continue; 1454 } 1455 touch = (!kn->kn_fop->f_isfd && 1456 kn->kn_fop->f_touch != NULL); 1457 if (touch) 1458 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1459 else 1460 *kevp = kn->kn_kevent; 1461 KQ_LOCK(kq); 1462 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1463 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1464 /* 1465 * Manually clear knotes who weren't 1466 * 'touch'ed. 1467 */ 1468 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1469 kn->kn_data = 0; 1470 kn->kn_fflags = 0; 1471 } 1472 if (kn->kn_flags & EV_DISPATCH) 1473 kn->kn_status |= KN_DISABLED; 1474 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1475 kq->kq_count--; 1476 } else 1477 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1478 1479 kn->kn_status &= ~(KN_INFLUX); 1480 KN_LIST_UNLOCK(kn); 1481 influx = 1; 1482 } 1483 1484 /* we are returning a copy to the user */ 1485 kevp++; 1486 nkev++; 1487 count--; 1488 1489 if (nkev == KQ_NEVENTS) { 1490 influx = 0; 1491 KQ_UNLOCK_FLUX(kq); 1492 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1493 nkev = 0; 1494 kevp = keva; 1495 KQ_LOCK(kq); 1496 if (error) 1497 break; 1498 } 1499 } 1500 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1501 done: 1502 KQ_OWNED(kq); 1503 KQ_UNLOCK_FLUX(kq); 1504 knote_free(marker); 1505 done_nl: 1506 KQ_NOTOWNED(kq); 1507 if (nkev != 0) 1508 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1509 td->td_retval[0] = maxevents - count; 1510 return (error); 1511 } 1512 1513 /* 1514 * XXX 1515 * This could be expanded to call kqueue_scan, if desired. 1516 */ 1517 /*ARGSUSED*/ 1518 static int 1519 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1520 int flags, struct thread *td) 1521 { 1522 return (ENXIO); 1523 } 1524 1525 /*ARGSUSED*/ 1526 static int 1527 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1528 int flags, struct thread *td) 1529 { 1530 return (ENXIO); 1531 } 1532 1533 /*ARGSUSED*/ 1534 static int 1535 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1536 struct thread *td) 1537 { 1538 1539 return (EINVAL); 1540 } 1541 1542 /*ARGSUSED*/ 1543 static int 1544 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1545 struct ucred *active_cred, struct thread *td) 1546 { 1547 /* 1548 * Enabling sigio causes two major problems: 1549 * 1) infinite recursion: 1550 * Synopsys: kevent is being used to track signals and have FIOASYNC 1551 * set. On receipt of a signal this will cause a kqueue to recurse 1552 * into itself over and over. Sending the sigio causes the kqueue 1553 * to become ready, which in turn posts sigio again, forever. 1554 * Solution: this can be solved by setting a flag in the kqueue that 1555 * we have a SIGIO in progress. 1556 * 2) locking problems: 1557 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1558 * us above the proc and pgrp locks. 1559 * Solution: Post a signal using an async mechanism, being sure to 1560 * record a generation count in the delivery so that we do not deliver 1561 * a signal to the wrong process. 1562 * 1563 * Note, these two mechanisms are somewhat mutually exclusive! 1564 */ 1565 #if 0 1566 struct kqueue *kq; 1567 1568 kq = fp->f_data; 1569 switch (cmd) { 1570 case FIOASYNC: 1571 if (*(int *)data) { 1572 kq->kq_state |= KQ_ASYNC; 1573 } else { 1574 kq->kq_state &= ~KQ_ASYNC; 1575 } 1576 return (0); 1577 1578 case FIOSETOWN: 1579 return (fsetown(*(int *)data, &kq->kq_sigio)); 1580 1581 case FIOGETOWN: 1582 *(int *)data = fgetown(&kq->kq_sigio); 1583 return (0); 1584 } 1585 #endif 1586 1587 return (ENOTTY); 1588 } 1589 1590 /*ARGSUSED*/ 1591 static int 1592 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1593 struct thread *td) 1594 { 1595 struct kqueue *kq; 1596 int revents = 0; 1597 int error; 1598 1599 if ((error = kqueue_acquire(fp, &kq))) 1600 return POLLERR; 1601 1602 KQ_LOCK(kq); 1603 if (events & (POLLIN | POLLRDNORM)) { 1604 if (kq->kq_count) { 1605 revents |= events & (POLLIN | POLLRDNORM); 1606 } else { 1607 selrecord(td, &kq->kq_sel); 1608 if (SEL_WAITING(&kq->kq_sel)) 1609 kq->kq_state |= KQ_SEL; 1610 } 1611 } 1612 kqueue_release(kq, 1); 1613 KQ_UNLOCK(kq); 1614 return (revents); 1615 } 1616 1617 /*ARGSUSED*/ 1618 static int 1619 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1620 struct thread *td) 1621 { 1622 1623 bzero((void *)st, sizeof *st); 1624 /* 1625 * We no longer return kq_count because the unlocked value is useless. 1626 * If you spent all this time getting the count, why not spend your 1627 * syscall better by calling kevent? 1628 * 1629 * XXX - This is needed for libc_r. 1630 */ 1631 st->st_mode = S_IFIFO; 1632 return (0); 1633 } 1634 1635 /*ARGSUSED*/ 1636 static int 1637 kqueue_close(struct file *fp, struct thread *td) 1638 { 1639 struct kqueue *kq = fp->f_data; 1640 struct filedesc *fdp; 1641 struct knote *kn; 1642 int i; 1643 int error; 1644 1645 if ((error = kqueue_acquire(fp, &kq))) 1646 return error; 1647 1648 KQ_LOCK(kq); 1649 1650 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1651 ("kqueue already closing")); 1652 kq->kq_state |= KQ_CLOSING; 1653 if (kq->kq_refcnt > 1) 1654 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1655 1656 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1657 fdp = kq->kq_fdp; 1658 1659 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1660 ("kqueue's knlist not empty")); 1661 1662 for (i = 0; i < kq->kq_knlistsize; i++) { 1663 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1664 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1665 kq->kq_state |= KQ_FLUXWAIT; 1666 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1667 continue; 1668 } 1669 kn->kn_status |= KN_INFLUX; 1670 KQ_UNLOCK(kq); 1671 if (!(kn->kn_status & KN_DETACHED)) 1672 kn->kn_fop->f_detach(kn); 1673 knote_drop(kn, td); 1674 KQ_LOCK(kq); 1675 } 1676 } 1677 if (kq->kq_knhashmask != 0) { 1678 for (i = 0; i <= kq->kq_knhashmask; i++) { 1679 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1680 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1681 kq->kq_state |= KQ_FLUXWAIT; 1682 msleep(kq, &kq->kq_lock, PSOCK, 1683 "kqclo2", 0); 1684 continue; 1685 } 1686 kn->kn_status |= KN_INFLUX; 1687 KQ_UNLOCK(kq); 1688 if (!(kn->kn_status & KN_DETACHED)) 1689 kn->kn_fop->f_detach(kn); 1690 knote_drop(kn, td); 1691 KQ_LOCK(kq); 1692 } 1693 } 1694 } 1695 1696 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1697 kq->kq_state |= KQ_TASKDRAIN; 1698 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1699 } 1700 1701 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1702 selwakeuppri(&kq->kq_sel, PSOCK); 1703 if (!SEL_WAITING(&kq->kq_sel)) 1704 kq->kq_state &= ~KQ_SEL; 1705 } 1706 1707 KQ_UNLOCK(kq); 1708 1709 FILEDESC_XLOCK(fdp); 1710 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); 1711 FILEDESC_XUNLOCK(fdp); 1712 1713 seldrain(&kq->kq_sel); 1714 knlist_destroy(&kq->kq_sel.si_note); 1715 mtx_destroy(&kq->kq_lock); 1716 kq->kq_fdp = NULL; 1717 1718 if (kq->kq_knhash != NULL) 1719 free(kq->kq_knhash, M_KQUEUE); 1720 if (kq->kq_knlist != NULL) 1721 free(kq->kq_knlist, M_KQUEUE); 1722 1723 funsetown(&kq->kq_sigio); 1724 free(kq, M_KQUEUE); 1725 fp->f_data = NULL; 1726 1727 return (0); 1728 } 1729 1730 static void 1731 kqueue_wakeup(struct kqueue *kq) 1732 { 1733 KQ_OWNED(kq); 1734 1735 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1736 kq->kq_state &= ~KQ_SLEEP; 1737 wakeup(kq); 1738 } 1739 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1740 selwakeuppri(&kq->kq_sel, PSOCK); 1741 if (!SEL_WAITING(&kq->kq_sel)) 1742 kq->kq_state &= ~KQ_SEL; 1743 } 1744 if (!knlist_empty(&kq->kq_sel.si_note)) 1745 kqueue_schedtask(kq); 1746 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1747 pgsigio(&kq->kq_sigio, SIGIO, 0); 1748 } 1749 } 1750 1751 /* 1752 * Walk down a list of knotes, activating them if their event has triggered. 1753 * 1754 * There is a possibility to optimize in the case of one kq watching another. 1755 * Instead of scheduling a task to wake it up, you could pass enough state 1756 * down the chain to make up the parent kqueue. Make this code functional 1757 * first. 1758 */ 1759 void 1760 knote(struct knlist *list, long hint, int lockflags) 1761 { 1762 struct kqueue *kq; 1763 struct knote *kn; 1764 int error; 1765 1766 if (list == NULL) 1767 return; 1768 1769 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1770 1771 if ((lockflags & KNF_LISTLOCKED) == 0) 1772 list->kl_lock(list->kl_lockarg); 1773 1774 /* 1775 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1776 * the kqueue scheduling, but this will introduce four 1777 * lock/unlock's for each knote to test. If we do, continue to use 1778 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1779 * only safe if you want to remove the current item, which we are 1780 * not doing. 1781 */ 1782 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1783 kq = kn->kn_kq; 1784 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1785 KQ_LOCK(kq); 1786 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1787 KQ_UNLOCK(kq); 1788 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1789 kn->kn_status |= KN_INFLUX; 1790 KQ_UNLOCK(kq); 1791 error = kn->kn_fop->f_event(kn, hint); 1792 KQ_LOCK(kq); 1793 kn->kn_status &= ~KN_INFLUX; 1794 if (error) 1795 KNOTE_ACTIVATE(kn, 1); 1796 KQ_UNLOCK_FLUX(kq); 1797 } else { 1798 kn->kn_status |= KN_HASKQLOCK; 1799 if (kn->kn_fop->f_event(kn, hint)) 1800 KNOTE_ACTIVATE(kn, 1); 1801 kn->kn_status &= ~KN_HASKQLOCK; 1802 KQ_UNLOCK(kq); 1803 } 1804 } 1805 kq = NULL; 1806 } 1807 if ((lockflags & KNF_LISTLOCKED) == 0) 1808 list->kl_unlock(list->kl_lockarg); 1809 } 1810 1811 /* 1812 * add a knote to a knlist 1813 */ 1814 void 1815 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1816 { 1817 KNL_ASSERT_LOCK(knl, islocked); 1818 KQ_NOTOWNED(kn->kn_kq); 1819 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1820 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1821 if (!islocked) 1822 knl->kl_lock(knl->kl_lockarg); 1823 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1824 if (!islocked) 1825 knl->kl_unlock(knl->kl_lockarg); 1826 KQ_LOCK(kn->kn_kq); 1827 kn->kn_knlist = knl; 1828 kn->kn_status &= ~KN_DETACHED; 1829 KQ_UNLOCK(kn->kn_kq); 1830 } 1831 1832 static void 1833 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1834 { 1835 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1836 KNL_ASSERT_LOCK(knl, knlislocked); 1837 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1838 if (!kqislocked) 1839 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1840 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1841 if (!knlislocked) 1842 knl->kl_lock(knl->kl_lockarg); 1843 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1844 kn->kn_knlist = NULL; 1845 if (!knlislocked) 1846 knl->kl_unlock(knl->kl_lockarg); 1847 if (!kqislocked) 1848 KQ_LOCK(kn->kn_kq); 1849 kn->kn_status |= KN_DETACHED; 1850 if (!kqislocked) 1851 KQ_UNLOCK(kn->kn_kq); 1852 } 1853 1854 /* 1855 * remove all knotes from a specified klist 1856 */ 1857 void 1858 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1859 { 1860 1861 knlist_remove_kq(knl, kn, islocked, 0); 1862 } 1863 1864 /* 1865 * remove knote from a specified klist while in f_event handler. 1866 */ 1867 void 1868 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1869 { 1870 1871 knlist_remove_kq(knl, kn, 1, 1872 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1873 } 1874 1875 int 1876 knlist_empty(struct knlist *knl) 1877 { 1878 KNL_ASSERT_LOCKED(knl); 1879 return SLIST_EMPTY(&knl->kl_list); 1880 } 1881 1882 static struct mtx knlist_lock; 1883 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1884 MTX_DEF); 1885 static void knlist_mtx_lock(void *arg); 1886 static void knlist_mtx_unlock(void *arg); 1887 1888 static void 1889 knlist_mtx_lock(void *arg) 1890 { 1891 mtx_lock((struct mtx *)arg); 1892 } 1893 1894 static void 1895 knlist_mtx_unlock(void *arg) 1896 { 1897 mtx_unlock((struct mtx *)arg); 1898 } 1899 1900 static void 1901 knlist_mtx_assert_locked(void *arg) 1902 { 1903 mtx_assert((struct mtx *)arg, MA_OWNED); 1904 } 1905 1906 static void 1907 knlist_mtx_assert_unlocked(void *arg) 1908 { 1909 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1910 } 1911 1912 void 1913 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 1914 void (*kl_unlock)(void *), 1915 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 1916 { 1917 1918 if (lock == NULL) 1919 knl->kl_lockarg = &knlist_lock; 1920 else 1921 knl->kl_lockarg = lock; 1922 1923 if (kl_lock == NULL) 1924 knl->kl_lock = knlist_mtx_lock; 1925 else 1926 knl->kl_lock = kl_lock; 1927 if (kl_unlock == NULL) 1928 knl->kl_unlock = knlist_mtx_unlock; 1929 else 1930 knl->kl_unlock = kl_unlock; 1931 if (kl_assert_locked == NULL) 1932 knl->kl_assert_locked = knlist_mtx_assert_locked; 1933 else 1934 knl->kl_assert_locked = kl_assert_locked; 1935 if (kl_assert_unlocked == NULL) 1936 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 1937 else 1938 knl->kl_assert_unlocked = kl_assert_unlocked; 1939 1940 SLIST_INIT(&knl->kl_list); 1941 } 1942 1943 void 1944 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 1945 { 1946 1947 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 1948 } 1949 1950 void 1951 knlist_destroy(struct knlist *knl) 1952 { 1953 1954 #ifdef INVARIANTS 1955 /* 1956 * if we run across this error, we need to find the offending 1957 * driver and have it call knlist_clear. 1958 */ 1959 if (!SLIST_EMPTY(&knl->kl_list)) 1960 printf("WARNING: destroying knlist w/ knotes on it!\n"); 1961 #endif 1962 1963 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 1964 SLIST_INIT(&knl->kl_list); 1965 } 1966 1967 /* 1968 * Even if we are locked, we may need to drop the lock to allow any influx 1969 * knotes time to "settle". 1970 */ 1971 void 1972 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 1973 { 1974 struct knote *kn, *kn2; 1975 struct kqueue *kq; 1976 1977 if (islocked) 1978 KNL_ASSERT_LOCKED(knl); 1979 else { 1980 KNL_ASSERT_UNLOCKED(knl); 1981 again: /* need to reacquire lock since we have dropped it */ 1982 knl->kl_lock(knl->kl_lockarg); 1983 } 1984 1985 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 1986 kq = kn->kn_kq; 1987 KQ_LOCK(kq); 1988 if ((kn->kn_status & KN_INFLUX)) { 1989 KQ_UNLOCK(kq); 1990 continue; 1991 } 1992 knlist_remove_kq(knl, kn, 1, 1); 1993 if (killkn) { 1994 kn->kn_status |= KN_INFLUX | KN_DETACHED; 1995 KQ_UNLOCK(kq); 1996 knote_drop(kn, td); 1997 } else { 1998 /* Make sure cleared knotes disappear soon */ 1999 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2000 KQ_UNLOCK(kq); 2001 } 2002 kq = NULL; 2003 } 2004 2005 if (!SLIST_EMPTY(&knl->kl_list)) { 2006 /* there are still KN_INFLUX remaining */ 2007 kn = SLIST_FIRST(&knl->kl_list); 2008 kq = kn->kn_kq; 2009 KQ_LOCK(kq); 2010 KASSERT(kn->kn_status & KN_INFLUX, 2011 ("knote removed w/o list lock")); 2012 knl->kl_unlock(knl->kl_lockarg); 2013 kq->kq_state |= KQ_FLUXWAIT; 2014 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2015 kq = NULL; 2016 goto again; 2017 } 2018 2019 if (islocked) 2020 KNL_ASSERT_LOCKED(knl); 2021 else { 2022 knl->kl_unlock(knl->kl_lockarg); 2023 KNL_ASSERT_UNLOCKED(knl); 2024 } 2025 } 2026 2027 /* 2028 * Remove all knotes referencing a specified fd must be called with FILEDESC 2029 * lock. This prevents a race where a new fd comes along and occupies the 2030 * entry and we attach a knote to the fd. 2031 */ 2032 void 2033 knote_fdclose(struct thread *td, int fd) 2034 { 2035 struct filedesc *fdp = td->td_proc->p_fd; 2036 struct kqueue *kq; 2037 struct knote *kn; 2038 int influx; 2039 2040 FILEDESC_XLOCK_ASSERT(fdp); 2041 2042 /* 2043 * We shouldn't have to worry about new kevents appearing on fd 2044 * since filedesc is locked. 2045 */ 2046 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2047 KQ_LOCK(kq); 2048 2049 again: 2050 influx = 0; 2051 while (kq->kq_knlistsize > fd && 2052 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2053 if (kn->kn_status & KN_INFLUX) { 2054 /* someone else might be waiting on our knote */ 2055 if (influx) 2056 wakeup(kq); 2057 kq->kq_state |= KQ_FLUXWAIT; 2058 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2059 goto again; 2060 } 2061 kn->kn_status |= KN_INFLUX; 2062 KQ_UNLOCK(kq); 2063 if (!(kn->kn_status & KN_DETACHED)) 2064 kn->kn_fop->f_detach(kn); 2065 knote_drop(kn, td); 2066 influx = 1; 2067 KQ_LOCK(kq); 2068 } 2069 KQ_UNLOCK_FLUX(kq); 2070 } 2071 } 2072 2073 static int 2074 knote_attach(struct knote *kn, struct kqueue *kq) 2075 { 2076 struct klist *list; 2077 2078 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2079 KQ_OWNED(kq); 2080 2081 if (kn->kn_fop->f_isfd) { 2082 if (kn->kn_id >= kq->kq_knlistsize) 2083 return ENOMEM; 2084 list = &kq->kq_knlist[kn->kn_id]; 2085 } else { 2086 if (kq->kq_knhash == NULL) 2087 return ENOMEM; 2088 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2089 } 2090 2091 SLIST_INSERT_HEAD(list, kn, kn_link); 2092 2093 return 0; 2094 } 2095 2096 /* 2097 * knote must already have been detached using the f_detach method. 2098 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2099 * to prevent other removal. 2100 */ 2101 static void 2102 knote_drop(struct knote *kn, struct thread *td) 2103 { 2104 struct kqueue *kq; 2105 struct klist *list; 2106 2107 kq = kn->kn_kq; 2108 2109 KQ_NOTOWNED(kq); 2110 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2111 ("knote_drop called without KN_INFLUX set in kn_status")); 2112 2113 KQ_LOCK(kq); 2114 if (kn->kn_fop->f_isfd) 2115 list = &kq->kq_knlist[kn->kn_id]; 2116 else 2117 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2118 2119 if (!SLIST_EMPTY(list)) 2120 SLIST_REMOVE(list, kn, knote, kn_link); 2121 if (kn->kn_status & KN_QUEUED) 2122 knote_dequeue(kn); 2123 KQ_UNLOCK_FLUX(kq); 2124 2125 if (kn->kn_fop->f_isfd) { 2126 fdrop(kn->kn_fp, td); 2127 kn->kn_fp = NULL; 2128 } 2129 kqueue_fo_release(kn->kn_kevent.filter); 2130 kn->kn_fop = NULL; 2131 knote_free(kn); 2132 } 2133 2134 static void 2135 knote_enqueue(struct knote *kn) 2136 { 2137 struct kqueue *kq = kn->kn_kq; 2138 2139 KQ_OWNED(kn->kn_kq); 2140 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2141 2142 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2143 kn->kn_status |= KN_QUEUED; 2144 kq->kq_count++; 2145 kqueue_wakeup(kq); 2146 } 2147 2148 static void 2149 knote_dequeue(struct knote *kn) 2150 { 2151 struct kqueue *kq = kn->kn_kq; 2152 2153 KQ_OWNED(kn->kn_kq); 2154 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2155 2156 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2157 kn->kn_status &= ~KN_QUEUED; 2158 kq->kq_count--; 2159 } 2160 2161 static void 2162 knote_init(void) 2163 { 2164 2165 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2166 NULL, NULL, UMA_ALIGN_PTR, 0); 2167 } 2168 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2169 2170 static struct knote * 2171 knote_alloc(int waitok) 2172 { 2173 return ((struct knote *)uma_zalloc(knote_zone, 2174 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2175 } 2176 2177 static void 2178 knote_free(struct knote *kn) 2179 { 2180 if (kn != NULL) 2181 uma_zfree(knote_zone, kn); 2182 } 2183 2184 /* 2185 * Register the kev w/ the kq specified by fd. 2186 */ 2187 int 2188 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2189 { 2190 struct kqueue *kq; 2191 struct file *fp; 2192 int error; 2193 2194 if ((error = fget(td, fd, &fp)) != 0) 2195 return (error); 2196 if ((error = kqueue_acquire(fp, &kq)) != 0) 2197 goto noacquire; 2198 2199 error = kqueue_register(kq, kev, td, waitok); 2200 2201 kqueue_release(kq, 0); 2202 2203 noacquire: 2204 fdrop(fp, td); 2205 2206 return error; 2207 }
Cache object: 50a981471efa143cb6577e45618a7dd4
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