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