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