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