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 #include "opt_kqueue.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/capsicum.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/rwlock.h> 42 #include <sys/proc.h> 43 #include <sys/malloc.h> 44 #include <sys/unistd.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/filio.h> 48 #include <sys/fcntl.h> 49 #include <sys/kthread.h> 50 #include <sys/selinfo.h> 51 #include <sys/stdatomic.h> 52 #include <sys/queue.h> 53 #include <sys/event.h> 54 #include <sys/eventvar.h> 55 #include <sys/poll.h> 56 #include <sys/protosw.h> 57 #include <sys/resourcevar.h> 58 #include <sys/sigio.h> 59 #include <sys/signalvar.h> 60 #include <sys/socket.h> 61 #include <sys/socketvar.h> 62 #include <sys/stat.h> 63 #include <sys/sysctl.h> 64 #include <sys/sysproto.h> 65 #include <sys/syscallsubr.h> 66 #include <sys/taskqueue.h> 67 #include <sys/uio.h> 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 72 #include <vm/uma.h> 73 74 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 75 76 /* 77 * This lock is used if multiple kq locks are required. This possibly 78 * should be made into a per proc lock. 79 */ 80 static struct mtx kq_global; 81 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 82 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 83 if (!haslck) \ 84 mtx_lock(lck); \ 85 haslck = 1; \ 86 } while (0) 87 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 88 if (haslck) \ 89 mtx_unlock(lck); \ 90 haslck = 0; \ 91 } while (0) 92 93 TASKQUEUE_DEFINE_THREAD(kqueue); 94 95 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 96 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 97 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 98 struct thread *td, int waitok); 99 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 100 static void kqueue_release(struct kqueue *kq, int locked); 101 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 102 uintptr_t ident, int waitok); 103 static void kqueue_task(void *arg, int pending); 104 static int kqueue_scan(struct kqueue *kq, int maxevents, 105 struct kevent_copyops *k_ops, 106 const struct timespec *timeout, 107 struct kevent *keva, struct thread *td); 108 static void kqueue_wakeup(struct kqueue *kq); 109 static struct filterops *kqueue_fo_find(int filt); 110 static void kqueue_fo_release(int filt); 111 112 static fo_rdwr_t kqueue_read; 113 static fo_rdwr_t kqueue_write; 114 static fo_truncate_t kqueue_truncate; 115 static fo_ioctl_t kqueue_ioctl; 116 static fo_poll_t kqueue_poll; 117 static fo_kqfilter_t kqueue_kqfilter; 118 static fo_stat_t kqueue_stat; 119 static fo_close_t kqueue_close; 120 121 static struct fileops kqueueops = { 122 .fo_read = kqueue_read, 123 .fo_write = kqueue_write, 124 .fo_truncate = kqueue_truncate, 125 .fo_ioctl = kqueue_ioctl, 126 .fo_poll = kqueue_poll, 127 .fo_kqfilter = kqueue_kqfilter, 128 .fo_stat = kqueue_stat, 129 .fo_close = kqueue_close, 130 .fo_chmod = invfo_chmod, 131 .fo_chown = invfo_chown, 132 .fo_sendfile = invfo_sendfile, 133 }; 134 135 static int knote_attach(struct knote *kn, struct kqueue *kq); 136 static void knote_drop(struct knote *kn, struct thread *td); 137 static void knote_enqueue(struct knote *kn); 138 static void knote_dequeue(struct knote *kn); 139 static void knote_init(void); 140 static struct knote *knote_alloc(int waitok); 141 static void knote_free(struct knote *kn); 142 143 static void filt_kqdetach(struct knote *kn); 144 static int filt_kqueue(struct knote *kn, long hint); 145 static int filt_procattach(struct knote *kn); 146 static void filt_procdetach(struct knote *kn); 147 static int filt_proc(struct knote *kn, long hint); 148 static int filt_fileattach(struct knote *kn); 149 static void filt_timerexpire(void *knx); 150 static int filt_timerattach(struct knote *kn); 151 static void filt_timerdetach(struct knote *kn); 152 static int filt_timer(struct knote *kn, long hint); 153 static int filt_userattach(struct knote *kn); 154 static void filt_userdetach(struct knote *kn); 155 static int filt_user(struct knote *kn, long hint); 156 static void filt_usertouch(struct knote *kn, struct kevent *kev, 157 u_long type); 158 159 static struct filterops file_filtops = { 160 .f_isfd = 1, 161 .f_attach = filt_fileattach, 162 }; 163 static struct filterops kqread_filtops = { 164 .f_isfd = 1, 165 .f_detach = filt_kqdetach, 166 .f_event = filt_kqueue, 167 }; 168 /* XXX - move to kern_proc.c? */ 169 static struct filterops proc_filtops = { 170 .f_isfd = 0, 171 .f_attach = filt_procattach, 172 .f_detach = filt_procdetach, 173 .f_event = filt_proc, 174 }; 175 static struct filterops timer_filtops = { 176 .f_isfd = 0, 177 .f_attach = filt_timerattach, 178 .f_detach = filt_timerdetach, 179 .f_event = filt_timer, 180 }; 181 static struct filterops user_filtops = { 182 .f_attach = filt_userattach, 183 .f_detach = filt_userdetach, 184 .f_event = filt_user, 185 .f_touch = filt_usertouch, 186 }; 187 188 static uma_zone_t knote_zone; 189 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 190 static unsigned int kq_calloutmax = 4 * 1024; 191 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 192 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 193 194 /* XXX - ensure not KN_INFLUX?? */ 195 #define KNOTE_ACTIVATE(kn, islock) do { \ 196 if ((islock)) \ 197 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 198 else \ 199 KQ_LOCK((kn)->kn_kq); \ 200 (kn)->kn_status |= KN_ACTIVE; \ 201 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 202 knote_enqueue((kn)); \ 203 if (!(islock)) \ 204 KQ_UNLOCK((kn)->kn_kq); \ 205 } while(0) 206 #define KQ_LOCK(kq) do { \ 207 mtx_lock(&(kq)->kq_lock); \ 208 } while (0) 209 #define KQ_FLUX_WAKEUP(kq) do { \ 210 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 211 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 212 wakeup((kq)); \ 213 } \ 214 } while (0) 215 #define KQ_UNLOCK_FLUX(kq) do { \ 216 KQ_FLUX_WAKEUP(kq); \ 217 mtx_unlock(&(kq)->kq_lock); \ 218 } while (0) 219 #define KQ_UNLOCK(kq) do { \ 220 mtx_unlock(&(kq)->kq_lock); \ 221 } while (0) 222 #define KQ_OWNED(kq) do { \ 223 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 224 } while (0) 225 #define KQ_NOTOWNED(kq) do { \ 226 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 227 } while (0) 228 #define KN_LIST_LOCK(kn) do { \ 229 if (kn->kn_knlist != NULL) \ 230 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 231 } while (0) 232 #define KN_LIST_UNLOCK(kn) do { \ 233 if (kn->kn_knlist != NULL) \ 234 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 235 } while (0) 236 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 237 if (islocked) \ 238 KNL_ASSERT_LOCKED(knl); \ 239 else \ 240 KNL_ASSERT_UNLOCKED(knl); \ 241 } while (0) 242 #ifdef INVARIANTS 243 #define KNL_ASSERT_LOCKED(knl) do { \ 244 knl->kl_assert_locked((knl)->kl_lockarg); \ 245 } while (0) 246 #define KNL_ASSERT_UNLOCKED(knl) do { \ 247 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 248 } while (0) 249 #else /* !INVARIANTS */ 250 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 251 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 252 #endif /* INVARIANTS */ 253 254 #ifndef KN_HASHSIZE 255 #define KN_HASHSIZE 64 /* XXX should be tunable */ 256 #endif 257 258 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 259 260 static int 261 filt_nullattach(struct knote *kn) 262 { 263 264 return (ENXIO); 265 }; 266 267 struct filterops null_filtops = { 268 .f_isfd = 0, 269 .f_attach = filt_nullattach, 270 }; 271 272 /* XXX - make SYSINIT to add these, and move into respective modules. */ 273 extern struct filterops sig_filtops; 274 extern struct filterops fs_filtops; 275 276 /* 277 * Table for for all system-defined filters. 278 */ 279 static struct mtx filterops_lock; 280 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 281 MTX_DEF); 282 static struct { 283 struct filterops *for_fop; 284 int for_refcnt; 285 } sysfilt_ops[EVFILT_SYSCOUNT] = { 286 { &file_filtops }, /* EVFILT_READ */ 287 { &file_filtops }, /* EVFILT_WRITE */ 288 { &null_filtops }, /* EVFILT_AIO */ 289 { &file_filtops }, /* EVFILT_VNODE */ 290 { &proc_filtops }, /* EVFILT_PROC */ 291 { &sig_filtops }, /* EVFILT_SIGNAL */ 292 { &timer_filtops }, /* EVFILT_TIMER */ 293 { &file_filtops }, /* EVFILT_PROCDESC */ 294 { &fs_filtops }, /* EVFILT_FS */ 295 { &null_filtops }, /* EVFILT_LIO */ 296 { &user_filtops }, /* EVFILT_USER */ 297 { &null_filtops }, /* EVFILT_SENDFILE */ 298 }; 299 300 /* 301 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 302 * method. 303 */ 304 static int 305 filt_fileattach(struct knote *kn) 306 { 307 308 return (fo_kqfilter(kn->kn_fp, kn)); 309 } 310 311 /*ARGSUSED*/ 312 static int 313 kqueue_kqfilter(struct file *fp, struct knote *kn) 314 { 315 struct kqueue *kq = kn->kn_fp->f_data; 316 317 if (kn->kn_filter != EVFILT_READ) 318 return (EINVAL); 319 320 kn->kn_status |= KN_KQUEUE; 321 kn->kn_fop = &kqread_filtops; 322 knlist_add(&kq->kq_sel.si_note, kn, 0); 323 324 return (0); 325 } 326 327 static void 328 filt_kqdetach(struct knote *kn) 329 { 330 struct kqueue *kq = kn->kn_fp->f_data; 331 332 knlist_remove(&kq->kq_sel.si_note, kn, 0); 333 } 334 335 /*ARGSUSED*/ 336 static int 337 filt_kqueue(struct knote *kn, long hint) 338 { 339 struct kqueue *kq = kn->kn_fp->f_data; 340 341 kn->kn_data = kq->kq_count; 342 return (kn->kn_data > 0); 343 } 344 345 /* XXX - move to kern_proc.c? */ 346 static int 347 filt_procattach(struct knote *kn) 348 { 349 struct proc *p; 350 int immediate; 351 int error; 352 353 immediate = 0; 354 p = pfind(kn->kn_id); 355 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 356 p = zpfind(kn->kn_id); 357 immediate = 1; 358 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 359 immediate = 1; 360 } 361 362 if (p == NULL) 363 return (ESRCH); 364 if ((error = p_cansee(curthread, p))) { 365 PROC_UNLOCK(p); 366 return (error); 367 } 368 369 kn->kn_ptr.p_proc = p; 370 kn->kn_flags |= EV_CLEAR; /* automatically set */ 371 372 /* 373 * internal flag indicating registration done by kernel 374 */ 375 if (kn->kn_flags & EV_FLAG1) { 376 kn->kn_data = kn->kn_sdata; /* ppid */ 377 kn->kn_fflags = NOTE_CHILD; 378 kn->kn_flags &= ~EV_FLAG1; 379 } 380 381 if (immediate == 0) 382 knlist_add(&p->p_klist, kn, 1); 383 384 /* 385 * Immediately activate any exit notes if the target process is a 386 * zombie. This is necessary to handle the case where the target 387 * process, e.g. a child, dies before the kevent is registered. 388 */ 389 if (immediate && filt_proc(kn, NOTE_EXIT)) 390 KNOTE_ACTIVATE(kn, 0); 391 392 PROC_UNLOCK(p); 393 394 return (0); 395 } 396 397 /* 398 * The knote may be attached to a different process, which may exit, 399 * leaving nothing for the knote to be attached to. So when the process 400 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 401 * it will be deleted when read out. However, as part of the knote deletion, 402 * this routine is called, so a check is needed to avoid actually performing 403 * a detach, because the original process does not exist any more. 404 */ 405 /* XXX - move to kern_proc.c? */ 406 static void 407 filt_procdetach(struct knote *kn) 408 { 409 struct proc *p; 410 411 p = kn->kn_ptr.p_proc; 412 knlist_remove(&p->p_klist, kn, 0); 413 kn->kn_ptr.p_proc = NULL; 414 } 415 416 /* XXX - move to kern_proc.c? */ 417 static int 418 filt_proc(struct knote *kn, long hint) 419 { 420 struct proc *p; 421 u_int event; 422 423 p = kn->kn_ptr.p_proc; 424 /* Mask off extra data. */ 425 event = (u_int)hint & NOTE_PCTRLMASK; 426 427 /* If the user is interested in this event, record it. */ 428 if (kn->kn_sfflags & event) 429 kn->kn_fflags |= event; 430 431 /* Process is gone, so flag the event as finished. */ 432 if (event == NOTE_EXIT) { 433 if (!(kn->kn_status & KN_DETACHED)) 434 knlist_remove_inevent(&p->p_klist, kn); 435 kn->kn_flags |= EV_EOF | EV_ONESHOT; 436 kn->kn_ptr.p_proc = NULL; 437 if (kn->kn_fflags & NOTE_EXIT) 438 kn->kn_data = p->p_xstat; 439 if (kn->kn_fflags == 0) 440 kn->kn_flags |= EV_DROP; 441 return (1); 442 } 443 444 return (kn->kn_fflags != 0); 445 } 446 447 /* 448 * Called when the process forked. It mostly does the same as the 449 * knote(), activating all knotes registered to be activated when the 450 * process forked. Additionally, for each knote attached to the 451 * parent, check whether user wants to track the new process. If so 452 * attach a new knote to it, and immediately report an event with the 453 * child's pid. 454 */ 455 void 456 knote_fork(struct knlist *list, int pid) 457 { 458 struct kqueue *kq; 459 struct knote *kn; 460 struct kevent kev; 461 int error; 462 463 if (list == NULL) 464 return; 465 list->kl_lock(list->kl_lockarg); 466 467 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 468 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 469 continue; 470 kq = kn->kn_kq; 471 KQ_LOCK(kq); 472 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 473 KQ_UNLOCK(kq); 474 continue; 475 } 476 477 /* 478 * The same as knote(), activate the event. 479 */ 480 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 481 kn->kn_status |= KN_HASKQLOCK; 482 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 483 KNOTE_ACTIVATE(kn, 1); 484 kn->kn_status &= ~KN_HASKQLOCK; 485 KQ_UNLOCK(kq); 486 continue; 487 } 488 489 /* 490 * The NOTE_TRACK case. In addition to the activation 491 * of the event, we need to register new event to 492 * track the child. Drop the locks in preparation for 493 * the call to kqueue_register(). 494 */ 495 kn->kn_status |= KN_INFLUX; 496 KQ_UNLOCK(kq); 497 list->kl_unlock(list->kl_lockarg); 498 499 /* 500 * Activate existing knote and register a knote with 501 * new process. 502 */ 503 kev.ident = pid; 504 kev.filter = kn->kn_filter; 505 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 506 kev.fflags = kn->kn_sfflags; 507 kev.data = kn->kn_id; /* parent */ 508 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 509 error = kqueue_register(kq, &kev, NULL, 0); 510 if (error) 511 kn->kn_fflags |= NOTE_TRACKERR; 512 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 513 KNOTE_ACTIVATE(kn, 0); 514 KQ_LOCK(kq); 515 kn->kn_status &= ~KN_INFLUX; 516 KQ_UNLOCK_FLUX(kq); 517 list->kl_lock(list->kl_lockarg); 518 } 519 list->kl_unlock(list->kl_lockarg); 520 } 521 522 /* 523 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 524 * interval timer support code. 525 */ 526 527 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \ 528 NOTE_NSECONDS) 529 530 static __inline sbintime_t 531 timer2sbintime(intptr_t data, int flags) 532 { 533 sbintime_t modifier; 534 535 switch (flags & NOTE_TIMER_PRECMASK) { 536 case NOTE_SECONDS: 537 modifier = SBT_1S; 538 break; 539 case NOTE_MSECONDS: /* FALLTHROUGH */ 540 case 0: 541 modifier = SBT_1MS; 542 break; 543 case NOTE_USECONDS: 544 modifier = SBT_1US; 545 break; 546 case NOTE_NSECONDS: 547 modifier = SBT_1NS; 548 break; 549 default: 550 return (-1); 551 } 552 553 #ifdef __LP64__ 554 if (data > SBT_MAX / modifier) 555 return (SBT_MAX); 556 #endif 557 return (modifier * data); 558 } 559 560 static void 561 filt_timerexpire(void *knx) 562 { 563 struct callout *calloutp; 564 struct knote *kn; 565 566 kn = knx; 567 kn->kn_data++; 568 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 569 570 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 571 calloutp = (struct callout *)kn->kn_hook; 572 callout_reset_sbt_on(calloutp, 573 timer2sbintime(kn->kn_sdata, kn->kn_sfflags), 0, 574 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 575 } 576 } 577 578 /* 579 * data contains amount of time to sleep 580 */ 581 static int 582 filt_timerattach(struct knote *kn) 583 { 584 struct callout *calloutp; 585 sbintime_t to; 586 unsigned int ncallouts; 587 588 if ((intptr_t)kn->kn_sdata < 0) 589 return (EINVAL); 590 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 591 kn->kn_sdata = 1; 592 /* Only precision unit are supported in flags so far */ 593 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) 594 return (EINVAL); 595 596 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 597 if (to < 0) 598 return (EINVAL); 599 600 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 601 do { 602 if (ncallouts >= kq_calloutmax) 603 return (ENOMEM); 604 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 605 &ncallouts, ncallouts + 1, memory_order_relaxed, 606 memory_order_relaxed)); 607 608 kn->kn_flags |= EV_CLEAR; /* automatically set */ 609 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 610 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 611 callout_init(calloutp, CALLOUT_MPSAFE); 612 kn->kn_hook = calloutp; 613 callout_reset_sbt_on(calloutp, to, 0, 614 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 615 616 return (0); 617 } 618 619 static void 620 filt_timerdetach(struct knote *kn) 621 { 622 struct callout *calloutp; 623 unsigned int old; 624 625 calloutp = (struct callout *)kn->kn_hook; 626 callout_drain(calloutp); 627 free(calloutp, M_KQUEUE); 628 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 629 KASSERT(old > 0, ("Number of callouts cannot become negative")); 630 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 631 } 632 633 static int 634 filt_timer(struct knote *kn, long hint) 635 { 636 637 return (kn->kn_data != 0); 638 } 639 640 static int 641 filt_userattach(struct knote *kn) 642 { 643 644 /* 645 * EVFILT_USER knotes are not attached to anything in the kernel. 646 */ 647 kn->kn_hook = NULL; 648 if (kn->kn_fflags & NOTE_TRIGGER) 649 kn->kn_hookid = 1; 650 else 651 kn->kn_hookid = 0; 652 return (0); 653 } 654 655 static void 656 filt_userdetach(__unused struct knote *kn) 657 { 658 659 /* 660 * EVFILT_USER knotes are not attached to anything in the kernel. 661 */ 662 } 663 664 static int 665 filt_user(struct knote *kn, __unused long hint) 666 { 667 668 return (kn->kn_hookid); 669 } 670 671 static void 672 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 673 { 674 u_int ffctrl; 675 676 switch (type) { 677 case EVENT_REGISTER: 678 if (kev->fflags & NOTE_TRIGGER) 679 kn->kn_hookid = 1; 680 681 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 682 kev->fflags &= NOTE_FFLAGSMASK; 683 switch (ffctrl) { 684 case NOTE_FFNOP: 685 break; 686 687 case NOTE_FFAND: 688 kn->kn_sfflags &= kev->fflags; 689 break; 690 691 case NOTE_FFOR: 692 kn->kn_sfflags |= kev->fflags; 693 break; 694 695 case NOTE_FFCOPY: 696 kn->kn_sfflags = kev->fflags; 697 break; 698 699 default: 700 /* XXX Return error? */ 701 break; 702 } 703 kn->kn_sdata = kev->data; 704 if (kev->flags & EV_CLEAR) { 705 kn->kn_hookid = 0; 706 kn->kn_data = 0; 707 kn->kn_fflags = 0; 708 } 709 break; 710 711 case EVENT_PROCESS: 712 *kev = kn->kn_kevent; 713 kev->fflags = kn->kn_sfflags; 714 kev->data = kn->kn_sdata; 715 if (kn->kn_flags & EV_CLEAR) { 716 kn->kn_hookid = 0; 717 kn->kn_data = 0; 718 kn->kn_fflags = 0; 719 } 720 break; 721 722 default: 723 panic("filt_usertouch() - invalid type (%ld)", type); 724 break; 725 } 726 } 727 728 int 729 sys_kqueue(struct thread *td, struct kqueue_args *uap) 730 { 731 struct filedesc *fdp; 732 struct kqueue *kq; 733 struct file *fp; 734 struct proc *p; 735 struct ucred *cred; 736 int fd, error; 737 738 p = td->td_proc; 739 cred = td->td_ucred; 740 crhold(cred); 741 PROC_LOCK(p); 742 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 743 RLIMIT_KQUEUES))) { 744 PROC_UNLOCK(p); 745 crfree(cred); 746 return (ENOMEM); 747 } 748 PROC_UNLOCK(p); 749 750 fdp = p->p_fd; 751 error = falloc(td, &fp, &fd, 0); 752 if (error) 753 goto done2; 754 755 /* An extra reference on `fp' has been held for us by falloc(). */ 756 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 757 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 758 TAILQ_INIT(&kq->kq_head); 759 kq->kq_fdp = fdp; 760 kq->kq_cred = cred; 761 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 762 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 763 764 FILEDESC_XLOCK(fdp); 765 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 766 FILEDESC_XUNLOCK(fdp); 767 768 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 769 fdrop(fp, td); 770 771 td->td_retval[0] = fd; 772 done2: 773 if (error != 0) { 774 chgkqcnt(cred->cr_ruidinfo, -1, 0); 775 crfree(cred); 776 } 777 return (error); 778 } 779 780 #ifndef _SYS_SYSPROTO_H_ 781 struct kevent_args { 782 int fd; 783 const struct kevent *changelist; 784 int nchanges; 785 struct kevent *eventlist; 786 int nevents; 787 const struct timespec *timeout; 788 }; 789 #endif 790 int 791 sys_kevent(struct thread *td, struct kevent_args *uap) 792 { 793 struct timespec ts, *tsp; 794 struct kevent_copyops k_ops = { uap, 795 kevent_copyout, 796 kevent_copyin}; 797 int error; 798 #ifdef KTRACE 799 struct uio ktruio; 800 struct iovec ktriov; 801 struct uio *ktruioin = NULL; 802 struct uio *ktruioout = NULL; 803 #endif 804 805 if (uap->timeout != NULL) { 806 error = copyin(uap->timeout, &ts, sizeof(ts)); 807 if (error) 808 return (error); 809 tsp = &ts; 810 } else 811 tsp = NULL; 812 813 #ifdef KTRACE 814 if (KTRPOINT(td, KTR_GENIO)) { 815 ktriov.iov_base = uap->changelist; 816 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 817 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 818 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 819 .uio_td = td }; 820 ktruioin = cloneuio(&ktruio); 821 ktriov.iov_base = uap->eventlist; 822 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 823 ktruioout = cloneuio(&ktruio); 824 } 825 #endif 826 827 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 828 &k_ops, tsp); 829 830 #ifdef KTRACE 831 if (ktruioin != NULL) { 832 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 833 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 834 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 835 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 836 } 837 #endif 838 839 return (error); 840 } 841 842 /* 843 * Copy 'count' items into the destination list pointed to by uap->eventlist. 844 */ 845 static int 846 kevent_copyout(void *arg, struct kevent *kevp, int count) 847 { 848 struct kevent_args *uap; 849 int error; 850 851 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 852 uap = (struct kevent_args *)arg; 853 854 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 855 if (error == 0) 856 uap->eventlist += count; 857 return (error); 858 } 859 860 /* 861 * Copy 'count' items from the list pointed to by uap->changelist. 862 */ 863 static int 864 kevent_copyin(void *arg, struct kevent *kevp, int count) 865 { 866 struct kevent_args *uap; 867 int error; 868 869 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 870 uap = (struct kevent_args *)arg; 871 872 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 873 if (error == 0) 874 uap->changelist += count; 875 return (error); 876 } 877 878 int 879 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 880 struct kevent_copyops *k_ops, const struct timespec *timeout) 881 { 882 struct kevent keva[KQ_NEVENTS]; 883 struct kevent *kevp, *changes; 884 struct kqueue *kq; 885 struct file *fp; 886 cap_rights_t rights; 887 int i, n, nerrors, error; 888 889 cap_rights_init(&rights); 890 if (nchanges > 0) 891 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 892 if (nevents > 0) 893 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 894 error = fget(td, fd, &rights, &fp); 895 if (error != 0) 896 return (error); 897 898 error = kqueue_acquire(fp, &kq); 899 if (error != 0) 900 goto done_norel; 901 902 nerrors = 0; 903 904 while (nchanges > 0) { 905 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 906 error = k_ops->k_copyin(k_ops->arg, keva, n); 907 if (error) 908 goto done; 909 changes = keva; 910 for (i = 0; i < n; i++) { 911 kevp = &changes[i]; 912 if (!kevp->filter) 913 continue; 914 kevp->flags &= ~EV_SYSFLAGS; 915 error = kqueue_register(kq, kevp, td, 1); 916 if (error || (kevp->flags & EV_RECEIPT)) { 917 if (nevents != 0) { 918 kevp->flags = EV_ERROR; 919 kevp->data = error; 920 (void) k_ops->k_copyout(k_ops->arg, 921 kevp, 1); 922 nevents--; 923 nerrors++; 924 } else { 925 goto done; 926 } 927 } 928 } 929 nchanges -= n; 930 } 931 if (nerrors) { 932 td->td_retval[0] = nerrors; 933 error = 0; 934 goto done; 935 } 936 937 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 938 done: 939 kqueue_release(kq, 0); 940 done_norel: 941 fdrop(fp, td); 942 return (error); 943 } 944 945 int 946 kqueue_add_filteropts(int filt, struct filterops *filtops) 947 { 948 int error; 949 950 error = 0; 951 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 952 printf( 953 "trying to add a filterop that is out of range: %d is beyond %d\n", 954 ~filt, EVFILT_SYSCOUNT); 955 return EINVAL; 956 } 957 mtx_lock(&filterops_lock); 958 if (sysfilt_ops[~filt].for_fop != &null_filtops && 959 sysfilt_ops[~filt].for_fop != NULL) 960 error = EEXIST; 961 else { 962 sysfilt_ops[~filt].for_fop = filtops; 963 sysfilt_ops[~filt].for_refcnt = 0; 964 } 965 mtx_unlock(&filterops_lock); 966 967 return (error); 968 } 969 970 int 971 kqueue_del_filteropts(int filt) 972 { 973 int error; 974 975 error = 0; 976 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 977 return EINVAL; 978 979 mtx_lock(&filterops_lock); 980 if (sysfilt_ops[~filt].for_fop == &null_filtops || 981 sysfilt_ops[~filt].for_fop == NULL) 982 error = EINVAL; 983 else if (sysfilt_ops[~filt].for_refcnt != 0) 984 error = EBUSY; 985 else { 986 sysfilt_ops[~filt].for_fop = &null_filtops; 987 sysfilt_ops[~filt].for_refcnt = 0; 988 } 989 mtx_unlock(&filterops_lock); 990 991 return error; 992 } 993 994 static struct filterops * 995 kqueue_fo_find(int filt) 996 { 997 998 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 999 return NULL; 1000 1001 mtx_lock(&filterops_lock); 1002 sysfilt_ops[~filt].for_refcnt++; 1003 if (sysfilt_ops[~filt].for_fop == NULL) 1004 sysfilt_ops[~filt].for_fop = &null_filtops; 1005 mtx_unlock(&filterops_lock); 1006 1007 return sysfilt_ops[~filt].for_fop; 1008 } 1009 1010 static void 1011 kqueue_fo_release(int filt) 1012 { 1013 1014 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1015 return; 1016 1017 mtx_lock(&filterops_lock); 1018 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1019 ("filter object refcount not valid on release")); 1020 sysfilt_ops[~filt].for_refcnt--; 1021 mtx_unlock(&filterops_lock); 1022 } 1023 1024 /* 1025 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1026 * influence if memory allocation should wait. Make sure it is 0 if you 1027 * hold any mutexes. 1028 */ 1029 static int 1030 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1031 { 1032 struct filterops *fops; 1033 struct file *fp; 1034 struct knote *kn, *tkn; 1035 cap_rights_t rights; 1036 int error, filt, event; 1037 int haskqglobal, filedesc_unlock; 1038 1039 fp = NULL; 1040 kn = NULL; 1041 error = 0; 1042 haskqglobal = 0; 1043 filedesc_unlock = 0; 1044 1045 filt = kev->filter; 1046 fops = kqueue_fo_find(filt); 1047 if (fops == NULL) 1048 return EINVAL; 1049 1050 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1051 1052 findkn: 1053 if (fops->f_isfd) { 1054 KASSERT(td != NULL, ("td is NULL")); 1055 error = fget(td, kev->ident, 1056 cap_rights_init(&rights, CAP_EVENT), &fp); 1057 if (error) 1058 goto done; 1059 1060 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1061 kev->ident, 0) != 0) { 1062 /* try again */ 1063 fdrop(fp, td); 1064 fp = NULL; 1065 error = kqueue_expand(kq, fops, kev->ident, waitok); 1066 if (error) 1067 goto done; 1068 goto findkn; 1069 } 1070 1071 if (fp->f_type == DTYPE_KQUEUE) { 1072 /* 1073 * if we add some inteligence about what we are doing, 1074 * we should be able to support events on ourselves. 1075 * We need to know when we are doing this to prevent 1076 * getting both the knlist lock and the kq lock since 1077 * they are the same thing. 1078 */ 1079 if (fp->f_data == kq) { 1080 error = EINVAL; 1081 goto done; 1082 } 1083 1084 /* 1085 * Pre-lock the filedesc before the global 1086 * lock mutex, see the comment in 1087 * kqueue_close(). 1088 */ 1089 FILEDESC_XLOCK(td->td_proc->p_fd); 1090 filedesc_unlock = 1; 1091 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1092 } 1093 1094 KQ_LOCK(kq); 1095 if (kev->ident < kq->kq_knlistsize) { 1096 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1097 if (kev->filter == kn->kn_filter) 1098 break; 1099 } 1100 } else { 1101 if ((kev->flags & EV_ADD) == EV_ADD) 1102 kqueue_expand(kq, fops, kev->ident, waitok); 1103 1104 KQ_LOCK(kq); 1105 if (kq->kq_knhashmask != 0) { 1106 struct klist *list; 1107 1108 list = &kq->kq_knhash[ 1109 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1110 SLIST_FOREACH(kn, list, kn_link) 1111 if (kev->ident == kn->kn_id && 1112 kev->filter == kn->kn_filter) 1113 break; 1114 } 1115 } 1116 1117 /* knote is in the process of changing, wait for it to stablize. */ 1118 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1119 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1120 if (filedesc_unlock) { 1121 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1122 filedesc_unlock = 0; 1123 } 1124 kq->kq_state |= KQ_FLUXWAIT; 1125 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1126 if (fp != NULL) { 1127 fdrop(fp, td); 1128 fp = NULL; 1129 } 1130 goto findkn; 1131 } 1132 1133 /* 1134 * kn now contains the matching knote, or NULL if no match 1135 */ 1136 if (kn == NULL) { 1137 if (kev->flags & EV_ADD) { 1138 kn = tkn; 1139 tkn = NULL; 1140 if (kn == NULL) { 1141 KQ_UNLOCK(kq); 1142 error = ENOMEM; 1143 goto done; 1144 } 1145 kn->kn_fp = fp; 1146 kn->kn_kq = kq; 1147 kn->kn_fop = fops; 1148 /* 1149 * apply reference counts to knote structure, and 1150 * do not release it at the end of this routine. 1151 */ 1152 fops = NULL; 1153 fp = NULL; 1154 1155 kn->kn_sfflags = kev->fflags; 1156 kn->kn_sdata = kev->data; 1157 kev->fflags = 0; 1158 kev->data = 0; 1159 kn->kn_kevent = *kev; 1160 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1161 EV_ENABLE | EV_DISABLE); 1162 kn->kn_status = KN_INFLUX|KN_DETACHED; 1163 1164 error = knote_attach(kn, kq); 1165 KQ_UNLOCK(kq); 1166 if (error != 0) { 1167 tkn = kn; 1168 goto done; 1169 } 1170 1171 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1172 knote_drop(kn, td); 1173 goto done; 1174 } 1175 KN_LIST_LOCK(kn); 1176 goto done_ev_add; 1177 } else { 1178 /* No matching knote and the EV_ADD flag is not set. */ 1179 KQ_UNLOCK(kq); 1180 error = ENOENT; 1181 goto done; 1182 } 1183 } 1184 1185 if (kev->flags & EV_DELETE) { 1186 kn->kn_status |= KN_INFLUX; 1187 KQ_UNLOCK(kq); 1188 if (!(kn->kn_status & KN_DETACHED)) 1189 kn->kn_fop->f_detach(kn); 1190 knote_drop(kn, td); 1191 goto done; 1192 } 1193 1194 /* 1195 * The user may change some filter values after the initial EV_ADD, 1196 * but doing so will not reset any filter which has already been 1197 * triggered. 1198 */ 1199 kn->kn_status |= KN_INFLUX | KN_SCAN; 1200 KQ_UNLOCK(kq); 1201 KN_LIST_LOCK(kn); 1202 kn->kn_kevent.udata = kev->udata; 1203 if (!fops->f_isfd && fops->f_touch != NULL) { 1204 fops->f_touch(kn, kev, EVENT_REGISTER); 1205 } else { 1206 kn->kn_sfflags = kev->fflags; 1207 kn->kn_sdata = kev->data; 1208 } 1209 1210 /* 1211 * We can get here with kn->kn_knlist == NULL. This can happen when 1212 * the initial attach event decides that the event is "completed" 1213 * already. i.e. filt_procattach is called on a zombie process. It 1214 * will call filt_proc which will remove it from the list, and NULL 1215 * kn_knlist. 1216 */ 1217 done_ev_add: 1218 event = kn->kn_fop->f_event(kn, 0); 1219 KQ_LOCK(kq); 1220 if (event) 1221 KNOTE_ACTIVATE(kn, 1); 1222 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1223 KN_LIST_UNLOCK(kn); 1224 1225 if ((kev->flags & EV_DISABLE) && 1226 ((kn->kn_status & KN_DISABLED) == 0)) { 1227 kn->kn_status |= KN_DISABLED; 1228 } 1229 1230 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1231 kn->kn_status &= ~KN_DISABLED; 1232 if ((kn->kn_status & KN_ACTIVE) && 1233 ((kn->kn_status & KN_QUEUED) == 0)) 1234 knote_enqueue(kn); 1235 } 1236 KQ_UNLOCK_FLUX(kq); 1237 1238 done: 1239 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1240 if (filedesc_unlock) 1241 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1242 if (fp != NULL) 1243 fdrop(fp, td); 1244 if (tkn != NULL) 1245 knote_free(tkn); 1246 if (fops != NULL) 1247 kqueue_fo_release(filt); 1248 return (error); 1249 } 1250 1251 static int 1252 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1253 { 1254 int error; 1255 struct kqueue *kq; 1256 1257 error = 0; 1258 1259 kq = fp->f_data; 1260 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1261 return (EBADF); 1262 *kqp = kq; 1263 KQ_LOCK(kq); 1264 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1265 KQ_UNLOCK(kq); 1266 return (EBADF); 1267 } 1268 kq->kq_refcnt++; 1269 KQ_UNLOCK(kq); 1270 1271 return error; 1272 } 1273 1274 static void 1275 kqueue_release(struct kqueue *kq, int locked) 1276 { 1277 if (locked) 1278 KQ_OWNED(kq); 1279 else 1280 KQ_LOCK(kq); 1281 kq->kq_refcnt--; 1282 if (kq->kq_refcnt == 1) 1283 wakeup(&kq->kq_refcnt); 1284 if (!locked) 1285 KQ_UNLOCK(kq); 1286 } 1287 1288 static void 1289 kqueue_schedtask(struct kqueue *kq) 1290 { 1291 1292 KQ_OWNED(kq); 1293 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1294 ("scheduling kqueue task while draining")); 1295 1296 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1297 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1298 kq->kq_state |= KQ_TASKSCHED; 1299 } 1300 } 1301 1302 /* 1303 * Expand the kq to make sure we have storage for fops/ident pair. 1304 * 1305 * Return 0 on success (or no work necessary), return errno on failure. 1306 * 1307 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1308 * If kqueue_register is called from a non-fd context, there usually/should 1309 * be no locks held. 1310 */ 1311 static int 1312 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1313 int waitok) 1314 { 1315 struct klist *list, *tmp_knhash, *to_free; 1316 u_long tmp_knhashmask; 1317 int size; 1318 int fd; 1319 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1320 1321 KQ_NOTOWNED(kq); 1322 1323 to_free = NULL; 1324 if (fops->f_isfd) { 1325 fd = ident; 1326 if (kq->kq_knlistsize <= fd) { 1327 size = kq->kq_knlistsize; 1328 while (size <= fd) 1329 size += KQEXTENT; 1330 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1331 if (list == NULL) 1332 return ENOMEM; 1333 KQ_LOCK(kq); 1334 if (kq->kq_knlistsize > fd) { 1335 to_free = list; 1336 list = NULL; 1337 } else { 1338 if (kq->kq_knlist != NULL) { 1339 bcopy(kq->kq_knlist, list, 1340 kq->kq_knlistsize * sizeof(*list)); 1341 to_free = kq->kq_knlist; 1342 kq->kq_knlist = NULL; 1343 } 1344 bzero((caddr_t)list + 1345 kq->kq_knlistsize * sizeof(*list), 1346 (size - kq->kq_knlistsize) * sizeof(*list)); 1347 kq->kq_knlistsize = size; 1348 kq->kq_knlist = list; 1349 } 1350 KQ_UNLOCK(kq); 1351 } 1352 } else { 1353 if (kq->kq_knhashmask == 0) { 1354 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1355 &tmp_knhashmask); 1356 if (tmp_knhash == NULL) 1357 return ENOMEM; 1358 KQ_LOCK(kq); 1359 if (kq->kq_knhashmask == 0) { 1360 kq->kq_knhash = tmp_knhash; 1361 kq->kq_knhashmask = tmp_knhashmask; 1362 } else { 1363 to_free = tmp_knhash; 1364 } 1365 KQ_UNLOCK(kq); 1366 } 1367 } 1368 free(to_free, M_KQUEUE); 1369 1370 KQ_NOTOWNED(kq); 1371 return 0; 1372 } 1373 1374 static void 1375 kqueue_task(void *arg, int pending) 1376 { 1377 struct kqueue *kq; 1378 int haskqglobal; 1379 1380 haskqglobal = 0; 1381 kq = arg; 1382 1383 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1384 KQ_LOCK(kq); 1385 1386 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1387 1388 kq->kq_state &= ~KQ_TASKSCHED; 1389 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1390 wakeup(&kq->kq_state); 1391 } 1392 KQ_UNLOCK(kq); 1393 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1394 } 1395 1396 /* 1397 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1398 * We treat KN_MARKER knotes as if they are INFLUX. 1399 */ 1400 static int 1401 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1402 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1403 { 1404 struct kevent *kevp; 1405 struct knote *kn, *marker; 1406 sbintime_t asbt, rsbt; 1407 int count, error, haskqglobal, influx, nkev, touch; 1408 1409 count = maxevents; 1410 nkev = 0; 1411 error = 0; 1412 haskqglobal = 0; 1413 1414 if (maxevents == 0) 1415 goto done_nl; 1416 1417 rsbt = 0; 1418 if (tsp != NULL) { 1419 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1420 tsp->tv_nsec >= 1000000000) { 1421 error = EINVAL; 1422 goto done_nl; 1423 } 1424 if (timespecisset(tsp)) { 1425 if (tsp->tv_sec <= INT32_MAX) { 1426 rsbt = tstosbt(*tsp); 1427 if (TIMESEL(&asbt, rsbt)) 1428 asbt += tc_tick_sbt; 1429 if (asbt <= SBT_MAX - rsbt) 1430 asbt += rsbt; 1431 else 1432 asbt = 0; 1433 rsbt >>= tc_precexp; 1434 } else 1435 asbt = 0; 1436 } else 1437 asbt = -1; 1438 } else 1439 asbt = 0; 1440 marker = knote_alloc(1); 1441 if (marker == NULL) { 1442 error = ENOMEM; 1443 goto done_nl; 1444 } 1445 marker->kn_status = KN_MARKER; 1446 KQ_LOCK(kq); 1447 1448 retry: 1449 kevp = keva; 1450 if (kq->kq_count == 0) { 1451 if (asbt == -1) { 1452 error = EWOULDBLOCK; 1453 } else { 1454 kq->kq_state |= KQ_SLEEP; 1455 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1456 "kqread", asbt, rsbt, C_ABSOLUTE); 1457 } 1458 if (error == 0) 1459 goto retry; 1460 /* don't restart after signals... */ 1461 if (error == ERESTART) 1462 error = EINTR; 1463 else if (error == EWOULDBLOCK) 1464 error = 0; 1465 goto done; 1466 } 1467 1468 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1469 influx = 0; 1470 while (count) { 1471 KQ_OWNED(kq); 1472 kn = TAILQ_FIRST(&kq->kq_head); 1473 1474 if ((kn->kn_status == KN_MARKER && kn != marker) || 1475 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1476 if (influx) { 1477 influx = 0; 1478 KQ_FLUX_WAKEUP(kq); 1479 } 1480 kq->kq_state |= KQ_FLUXWAIT; 1481 error = msleep(kq, &kq->kq_lock, PSOCK, 1482 "kqflxwt", 0); 1483 continue; 1484 } 1485 1486 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1487 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1488 kn->kn_status &= ~KN_QUEUED; 1489 kq->kq_count--; 1490 continue; 1491 } 1492 if (kn == marker) { 1493 KQ_FLUX_WAKEUP(kq); 1494 if (count == maxevents) 1495 goto retry; 1496 goto done; 1497 } 1498 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1499 ("KN_INFLUX set when not suppose to be")); 1500 1501 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1502 kn->kn_status &= ~KN_QUEUED; 1503 kn->kn_status |= KN_INFLUX; 1504 kq->kq_count--; 1505 KQ_UNLOCK(kq); 1506 /* 1507 * We don't need to lock the list since we've marked 1508 * it _INFLUX. 1509 */ 1510 if (!(kn->kn_status & KN_DETACHED)) 1511 kn->kn_fop->f_detach(kn); 1512 knote_drop(kn, td); 1513 KQ_LOCK(kq); 1514 continue; 1515 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1516 kn->kn_status &= ~KN_QUEUED; 1517 kn->kn_status |= KN_INFLUX; 1518 kq->kq_count--; 1519 KQ_UNLOCK(kq); 1520 /* 1521 * We don't need to lock the list since we've marked 1522 * it _INFLUX. 1523 */ 1524 *kevp = kn->kn_kevent; 1525 if (!(kn->kn_status & KN_DETACHED)) 1526 kn->kn_fop->f_detach(kn); 1527 knote_drop(kn, td); 1528 KQ_LOCK(kq); 1529 kn = NULL; 1530 } else { 1531 kn->kn_status |= KN_INFLUX | KN_SCAN; 1532 KQ_UNLOCK(kq); 1533 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1534 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1535 KN_LIST_LOCK(kn); 1536 if (kn->kn_fop->f_event(kn, 0) == 0) { 1537 KQ_LOCK(kq); 1538 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1539 kn->kn_status &= 1540 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1541 KN_SCAN); 1542 kq->kq_count--; 1543 KN_LIST_UNLOCK(kn); 1544 influx = 1; 1545 continue; 1546 } 1547 touch = (!kn->kn_fop->f_isfd && 1548 kn->kn_fop->f_touch != NULL); 1549 if (touch) 1550 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1551 else 1552 *kevp = kn->kn_kevent; 1553 KQ_LOCK(kq); 1554 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1555 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1556 /* 1557 * Manually clear knotes who weren't 1558 * 'touch'ed. 1559 */ 1560 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1561 kn->kn_data = 0; 1562 kn->kn_fflags = 0; 1563 } 1564 if (kn->kn_flags & EV_DISPATCH) 1565 kn->kn_status |= KN_DISABLED; 1566 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1567 kq->kq_count--; 1568 } else 1569 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1570 1571 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1572 KN_LIST_UNLOCK(kn); 1573 influx = 1; 1574 } 1575 1576 /* we are returning a copy to the user */ 1577 kevp++; 1578 nkev++; 1579 count--; 1580 1581 if (nkev == KQ_NEVENTS) { 1582 influx = 0; 1583 KQ_UNLOCK_FLUX(kq); 1584 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1585 nkev = 0; 1586 kevp = keva; 1587 KQ_LOCK(kq); 1588 if (error) 1589 break; 1590 } 1591 } 1592 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1593 done: 1594 KQ_OWNED(kq); 1595 KQ_UNLOCK_FLUX(kq); 1596 knote_free(marker); 1597 done_nl: 1598 KQ_NOTOWNED(kq); 1599 if (nkev != 0) 1600 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1601 td->td_retval[0] = maxevents - count; 1602 return (error); 1603 } 1604 1605 /* 1606 * XXX 1607 * This could be expanded to call kqueue_scan, if desired. 1608 */ 1609 /*ARGSUSED*/ 1610 static int 1611 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1612 int flags, struct thread *td) 1613 { 1614 return (ENXIO); 1615 } 1616 1617 /*ARGSUSED*/ 1618 static int 1619 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1620 int flags, struct thread *td) 1621 { 1622 return (ENXIO); 1623 } 1624 1625 /*ARGSUSED*/ 1626 static int 1627 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1628 struct thread *td) 1629 { 1630 1631 return (EINVAL); 1632 } 1633 1634 /*ARGSUSED*/ 1635 static int 1636 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1637 struct ucred *active_cred, struct thread *td) 1638 { 1639 /* 1640 * Enabling sigio causes two major problems: 1641 * 1) infinite recursion: 1642 * Synopsys: kevent is being used to track signals and have FIOASYNC 1643 * set. On receipt of a signal this will cause a kqueue to recurse 1644 * into itself over and over. Sending the sigio causes the kqueue 1645 * to become ready, which in turn posts sigio again, forever. 1646 * Solution: this can be solved by setting a flag in the kqueue that 1647 * we have a SIGIO in progress. 1648 * 2) locking problems: 1649 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1650 * us above the proc and pgrp locks. 1651 * Solution: Post a signal using an async mechanism, being sure to 1652 * record a generation count in the delivery so that we do not deliver 1653 * a signal to the wrong process. 1654 * 1655 * Note, these two mechanisms are somewhat mutually exclusive! 1656 */ 1657 #if 0 1658 struct kqueue *kq; 1659 1660 kq = fp->f_data; 1661 switch (cmd) { 1662 case FIOASYNC: 1663 if (*(int *)data) { 1664 kq->kq_state |= KQ_ASYNC; 1665 } else { 1666 kq->kq_state &= ~KQ_ASYNC; 1667 } 1668 return (0); 1669 1670 case FIOSETOWN: 1671 return (fsetown(*(int *)data, &kq->kq_sigio)); 1672 1673 case FIOGETOWN: 1674 *(int *)data = fgetown(&kq->kq_sigio); 1675 return (0); 1676 } 1677 #endif 1678 1679 return (ENOTTY); 1680 } 1681 1682 /*ARGSUSED*/ 1683 static int 1684 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1685 struct thread *td) 1686 { 1687 struct kqueue *kq; 1688 int revents = 0; 1689 int error; 1690 1691 if ((error = kqueue_acquire(fp, &kq))) 1692 return POLLERR; 1693 1694 KQ_LOCK(kq); 1695 if (events & (POLLIN | POLLRDNORM)) { 1696 if (kq->kq_count) { 1697 revents |= events & (POLLIN | POLLRDNORM); 1698 } else { 1699 selrecord(td, &kq->kq_sel); 1700 if (SEL_WAITING(&kq->kq_sel)) 1701 kq->kq_state |= KQ_SEL; 1702 } 1703 } 1704 kqueue_release(kq, 1); 1705 KQ_UNLOCK(kq); 1706 return (revents); 1707 } 1708 1709 /*ARGSUSED*/ 1710 static int 1711 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1712 struct thread *td) 1713 { 1714 1715 bzero((void *)st, sizeof *st); 1716 /* 1717 * We no longer return kq_count because the unlocked value is useless. 1718 * If you spent all this time getting the count, why not spend your 1719 * syscall better by calling kevent? 1720 * 1721 * XXX - This is needed for libc_r. 1722 */ 1723 st->st_mode = S_IFIFO; 1724 return (0); 1725 } 1726 1727 /*ARGSUSED*/ 1728 static int 1729 kqueue_close(struct file *fp, struct thread *td) 1730 { 1731 struct kqueue *kq = fp->f_data; 1732 struct filedesc *fdp; 1733 struct knote *kn; 1734 int i; 1735 int error; 1736 int filedesc_unlock; 1737 1738 if ((error = kqueue_acquire(fp, &kq))) 1739 return error; 1740 1741 filedesc_unlock = 0; 1742 KQ_LOCK(kq); 1743 1744 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1745 ("kqueue already closing")); 1746 kq->kq_state |= KQ_CLOSING; 1747 if (kq->kq_refcnt > 1) 1748 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1749 1750 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1751 fdp = kq->kq_fdp; 1752 1753 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1754 ("kqueue's knlist not empty")); 1755 1756 for (i = 0; i < kq->kq_knlistsize; i++) { 1757 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1758 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1759 kq->kq_state |= KQ_FLUXWAIT; 1760 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1761 continue; 1762 } 1763 kn->kn_status |= KN_INFLUX; 1764 KQ_UNLOCK(kq); 1765 if (!(kn->kn_status & KN_DETACHED)) 1766 kn->kn_fop->f_detach(kn); 1767 knote_drop(kn, td); 1768 KQ_LOCK(kq); 1769 } 1770 } 1771 if (kq->kq_knhashmask != 0) { 1772 for (i = 0; i <= kq->kq_knhashmask; i++) { 1773 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1774 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1775 kq->kq_state |= KQ_FLUXWAIT; 1776 msleep(kq, &kq->kq_lock, PSOCK, 1777 "kqclo2", 0); 1778 continue; 1779 } 1780 kn->kn_status |= KN_INFLUX; 1781 KQ_UNLOCK(kq); 1782 if (!(kn->kn_status & KN_DETACHED)) 1783 kn->kn_fop->f_detach(kn); 1784 knote_drop(kn, td); 1785 KQ_LOCK(kq); 1786 } 1787 } 1788 } 1789 1790 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1791 kq->kq_state |= KQ_TASKDRAIN; 1792 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1793 } 1794 1795 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1796 selwakeuppri(&kq->kq_sel, PSOCK); 1797 if (!SEL_WAITING(&kq->kq_sel)) 1798 kq->kq_state &= ~KQ_SEL; 1799 } 1800 1801 KQ_UNLOCK(kq); 1802 1803 /* 1804 * We could be called due to the knote_drop() doing fdrop(), 1805 * called from kqueue_register(). In this case the global 1806 * lock is owned, and filedesc sx is locked before, to not 1807 * take the sleepable lock after non-sleepable. 1808 */ 1809 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1810 FILEDESC_XLOCK(fdp); 1811 filedesc_unlock = 1; 1812 } else 1813 filedesc_unlock = 0; 1814 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1815 if (filedesc_unlock) 1816 FILEDESC_XUNLOCK(fdp); 1817 1818 seldrain(&kq->kq_sel); 1819 knlist_destroy(&kq->kq_sel.si_note); 1820 mtx_destroy(&kq->kq_lock); 1821 kq->kq_fdp = NULL; 1822 1823 if (kq->kq_knhash != NULL) 1824 free(kq->kq_knhash, M_KQUEUE); 1825 if (kq->kq_knlist != NULL) 1826 free(kq->kq_knlist, M_KQUEUE); 1827 1828 funsetown(&kq->kq_sigio); 1829 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1830 crfree(kq->kq_cred); 1831 free(kq, M_KQUEUE); 1832 fp->f_data = NULL; 1833 1834 return (0); 1835 } 1836 1837 static void 1838 kqueue_wakeup(struct kqueue *kq) 1839 { 1840 KQ_OWNED(kq); 1841 1842 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1843 kq->kq_state &= ~KQ_SLEEP; 1844 wakeup(kq); 1845 } 1846 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1847 selwakeuppri(&kq->kq_sel, PSOCK); 1848 if (!SEL_WAITING(&kq->kq_sel)) 1849 kq->kq_state &= ~KQ_SEL; 1850 } 1851 if (!knlist_empty(&kq->kq_sel.si_note)) 1852 kqueue_schedtask(kq); 1853 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1854 pgsigio(&kq->kq_sigio, SIGIO, 0); 1855 } 1856 } 1857 1858 /* 1859 * Walk down a list of knotes, activating them if their event has triggered. 1860 * 1861 * There is a possibility to optimize in the case of one kq watching another. 1862 * Instead of scheduling a task to wake it up, you could pass enough state 1863 * down the chain to make up the parent kqueue. Make this code functional 1864 * first. 1865 */ 1866 void 1867 knote(struct knlist *list, long hint, int lockflags) 1868 { 1869 struct kqueue *kq; 1870 struct knote *kn; 1871 int error; 1872 1873 if (list == NULL) 1874 return; 1875 1876 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1877 1878 if ((lockflags & KNF_LISTLOCKED) == 0) 1879 list->kl_lock(list->kl_lockarg); 1880 1881 /* 1882 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1883 * the kqueue scheduling, but this will introduce four 1884 * lock/unlock's for each knote to test. If we do, continue to use 1885 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1886 * only safe if you want to remove the current item, which we are 1887 * not doing. 1888 */ 1889 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1890 kq = kn->kn_kq; 1891 KQ_LOCK(kq); 1892 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1893 /* 1894 * Do not process the influx notes, except for 1895 * the influx coming from the kq unlock in the 1896 * kqueue_scan(). In the later case, we do 1897 * not interfere with the scan, since the code 1898 * fragment in kqueue_scan() locks the knlist, 1899 * and cannot proceed until we finished. 1900 */ 1901 KQ_UNLOCK(kq); 1902 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1903 kn->kn_status |= KN_INFLUX; 1904 KQ_UNLOCK(kq); 1905 error = kn->kn_fop->f_event(kn, hint); 1906 KQ_LOCK(kq); 1907 kn->kn_status &= ~KN_INFLUX; 1908 if (error) 1909 KNOTE_ACTIVATE(kn, 1); 1910 KQ_UNLOCK_FLUX(kq); 1911 } else { 1912 kn->kn_status |= KN_HASKQLOCK; 1913 if (kn->kn_fop->f_event(kn, hint)) 1914 KNOTE_ACTIVATE(kn, 1); 1915 kn->kn_status &= ~KN_HASKQLOCK; 1916 KQ_UNLOCK(kq); 1917 } 1918 } 1919 if ((lockflags & KNF_LISTLOCKED) == 0) 1920 list->kl_unlock(list->kl_lockarg); 1921 } 1922 1923 /* 1924 * add a knote to a knlist 1925 */ 1926 void 1927 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1928 { 1929 KNL_ASSERT_LOCK(knl, islocked); 1930 KQ_NOTOWNED(kn->kn_kq); 1931 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1932 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1933 if (!islocked) 1934 knl->kl_lock(knl->kl_lockarg); 1935 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1936 if (!islocked) 1937 knl->kl_unlock(knl->kl_lockarg); 1938 KQ_LOCK(kn->kn_kq); 1939 kn->kn_knlist = knl; 1940 kn->kn_status &= ~KN_DETACHED; 1941 KQ_UNLOCK(kn->kn_kq); 1942 } 1943 1944 static void 1945 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1946 { 1947 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1948 KNL_ASSERT_LOCK(knl, knlislocked); 1949 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1950 if (!kqislocked) 1951 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1952 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1953 if (!knlislocked) 1954 knl->kl_lock(knl->kl_lockarg); 1955 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1956 kn->kn_knlist = NULL; 1957 if (!knlislocked) 1958 knl->kl_unlock(knl->kl_lockarg); 1959 if (!kqislocked) 1960 KQ_LOCK(kn->kn_kq); 1961 kn->kn_status |= KN_DETACHED; 1962 if (!kqislocked) 1963 KQ_UNLOCK(kn->kn_kq); 1964 } 1965 1966 /* 1967 * remove knote from the specified knlist 1968 */ 1969 void 1970 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1971 { 1972 1973 knlist_remove_kq(knl, kn, islocked, 0); 1974 } 1975 1976 /* 1977 * remove knote from the specified knlist while in f_event handler. 1978 */ 1979 void 1980 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1981 { 1982 1983 knlist_remove_kq(knl, kn, 1, 1984 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1985 } 1986 1987 int 1988 knlist_empty(struct knlist *knl) 1989 { 1990 1991 KNL_ASSERT_LOCKED(knl); 1992 return SLIST_EMPTY(&knl->kl_list); 1993 } 1994 1995 static struct mtx knlist_lock; 1996 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1997 MTX_DEF); 1998 static void knlist_mtx_lock(void *arg); 1999 static void knlist_mtx_unlock(void *arg); 2000 2001 static void 2002 knlist_mtx_lock(void *arg) 2003 { 2004 2005 mtx_lock((struct mtx *)arg); 2006 } 2007 2008 static void 2009 knlist_mtx_unlock(void *arg) 2010 { 2011 2012 mtx_unlock((struct mtx *)arg); 2013 } 2014 2015 static void 2016 knlist_mtx_assert_locked(void *arg) 2017 { 2018 2019 mtx_assert((struct mtx *)arg, MA_OWNED); 2020 } 2021 2022 static void 2023 knlist_mtx_assert_unlocked(void *arg) 2024 { 2025 2026 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2027 } 2028 2029 static void 2030 knlist_rw_rlock(void *arg) 2031 { 2032 2033 rw_rlock((struct rwlock *)arg); 2034 } 2035 2036 static void 2037 knlist_rw_runlock(void *arg) 2038 { 2039 2040 rw_runlock((struct rwlock *)arg); 2041 } 2042 2043 static void 2044 knlist_rw_assert_locked(void *arg) 2045 { 2046 2047 rw_assert((struct rwlock *)arg, RA_LOCKED); 2048 } 2049 2050 static void 2051 knlist_rw_assert_unlocked(void *arg) 2052 { 2053 2054 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2055 } 2056 2057 void 2058 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2059 void (*kl_unlock)(void *), 2060 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2061 { 2062 2063 if (lock == NULL) 2064 knl->kl_lockarg = &knlist_lock; 2065 else 2066 knl->kl_lockarg = lock; 2067 2068 if (kl_lock == NULL) 2069 knl->kl_lock = knlist_mtx_lock; 2070 else 2071 knl->kl_lock = kl_lock; 2072 if (kl_unlock == NULL) 2073 knl->kl_unlock = knlist_mtx_unlock; 2074 else 2075 knl->kl_unlock = kl_unlock; 2076 if (kl_assert_locked == NULL) 2077 knl->kl_assert_locked = knlist_mtx_assert_locked; 2078 else 2079 knl->kl_assert_locked = kl_assert_locked; 2080 if (kl_assert_unlocked == NULL) 2081 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2082 else 2083 knl->kl_assert_unlocked = kl_assert_unlocked; 2084 2085 SLIST_INIT(&knl->kl_list); 2086 } 2087 2088 void 2089 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2090 { 2091 2092 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2093 } 2094 2095 void 2096 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2097 { 2098 2099 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2100 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2101 } 2102 2103 void 2104 knlist_destroy(struct knlist *knl) 2105 { 2106 2107 #ifdef INVARIANTS 2108 /* 2109 * if we run across this error, we need to find the offending 2110 * driver and have it call knlist_clear or knlist_delete. 2111 */ 2112 if (!SLIST_EMPTY(&knl->kl_list)) 2113 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2114 #endif 2115 2116 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2117 SLIST_INIT(&knl->kl_list); 2118 } 2119 2120 /* 2121 * Even if we are locked, we may need to drop the lock to allow any influx 2122 * knotes time to "settle". 2123 */ 2124 void 2125 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2126 { 2127 struct knote *kn, *kn2; 2128 struct kqueue *kq; 2129 2130 if (islocked) 2131 KNL_ASSERT_LOCKED(knl); 2132 else { 2133 KNL_ASSERT_UNLOCKED(knl); 2134 again: /* need to reacquire lock since we have dropped it */ 2135 knl->kl_lock(knl->kl_lockarg); 2136 } 2137 2138 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2139 kq = kn->kn_kq; 2140 KQ_LOCK(kq); 2141 if ((kn->kn_status & KN_INFLUX)) { 2142 KQ_UNLOCK(kq); 2143 continue; 2144 } 2145 knlist_remove_kq(knl, kn, 1, 1); 2146 if (killkn) { 2147 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2148 KQ_UNLOCK(kq); 2149 knote_drop(kn, td); 2150 } else { 2151 /* Make sure cleared knotes disappear soon */ 2152 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2153 KQ_UNLOCK(kq); 2154 } 2155 kq = NULL; 2156 } 2157 2158 if (!SLIST_EMPTY(&knl->kl_list)) { 2159 /* there are still KN_INFLUX remaining */ 2160 kn = SLIST_FIRST(&knl->kl_list); 2161 kq = kn->kn_kq; 2162 KQ_LOCK(kq); 2163 KASSERT(kn->kn_status & KN_INFLUX, 2164 ("knote removed w/o list lock")); 2165 knl->kl_unlock(knl->kl_lockarg); 2166 kq->kq_state |= KQ_FLUXWAIT; 2167 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2168 kq = NULL; 2169 goto again; 2170 } 2171 2172 if (islocked) 2173 KNL_ASSERT_LOCKED(knl); 2174 else { 2175 knl->kl_unlock(knl->kl_lockarg); 2176 KNL_ASSERT_UNLOCKED(knl); 2177 } 2178 } 2179 2180 /* 2181 * Remove all knotes referencing a specified fd must be called with FILEDESC 2182 * lock. This prevents a race where a new fd comes along and occupies the 2183 * entry and we attach a knote to the fd. 2184 */ 2185 void 2186 knote_fdclose(struct thread *td, int fd) 2187 { 2188 struct filedesc *fdp = td->td_proc->p_fd; 2189 struct kqueue *kq; 2190 struct knote *kn; 2191 int influx; 2192 2193 FILEDESC_XLOCK_ASSERT(fdp); 2194 2195 /* 2196 * We shouldn't have to worry about new kevents appearing on fd 2197 * since filedesc is locked. 2198 */ 2199 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2200 KQ_LOCK(kq); 2201 2202 again: 2203 influx = 0; 2204 while (kq->kq_knlistsize > fd && 2205 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2206 if (kn->kn_status & KN_INFLUX) { 2207 /* someone else might be waiting on our knote */ 2208 if (influx) 2209 wakeup(kq); 2210 kq->kq_state |= KQ_FLUXWAIT; 2211 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2212 goto again; 2213 } 2214 kn->kn_status |= KN_INFLUX; 2215 KQ_UNLOCK(kq); 2216 if (!(kn->kn_status & KN_DETACHED)) 2217 kn->kn_fop->f_detach(kn); 2218 knote_drop(kn, td); 2219 influx = 1; 2220 KQ_LOCK(kq); 2221 } 2222 KQ_UNLOCK_FLUX(kq); 2223 } 2224 } 2225 2226 static int 2227 knote_attach(struct knote *kn, struct kqueue *kq) 2228 { 2229 struct klist *list; 2230 2231 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2232 KQ_OWNED(kq); 2233 2234 if (kn->kn_fop->f_isfd) { 2235 if (kn->kn_id >= kq->kq_knlistsize) 2236 return ENOMEM; 2237 list = &kq->kq_knlist[kn->kn_id]; 2238 } else { 2239 if (kq->kq_knhash == NULL) 2240 return ENOMEM; 2241 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2242 } 2243 2244 SLIST_INSERT_HEAD(list, kn, kn_link); 2245 2246 return 0; 2247 } 2248 2249 /* 2250 * knote must already have been detached using the f_detach method. 2251 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2252 * to prevent other removal. 2253 */ 2254 static void 2255 knote_drop(struct knote *kn, struct thread *td) 2256 { 2257 struct kqueue *kq; 2258 struct klist *list; 2259 2260 kq = kn->kn_kq; 2261 2262 KQ_NOTOWNED(kq); 2263 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2264 ("knote_drop called without KN_INFLUX set in kn_status")); 2265 2266 KQ_LOCK(kq); 2267 if (kn->kn_fop->f_isfd) 2268 list = &kq->kq_knlist[kn->kn_id]; 2269 else 2270 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2271 2272 if (!SLIST_EMPTY(list)) 2273 SLIST_REMOVE(list, kn, knote, kn_link); 2274 if (kn->kn_status & KN_QUEUED) 2275 knote_dequeue(kn); 2276 KQ_UNLOCK_FLUX(kq); 2277 2278 if (kn->kn_fop->f_isfd) { 2279 fdrop(kn->kn_fp, td); 2280 kn->kn_fp = NULL; 2281 } 2282 kqueue_fo_release(kn->kn_kevent.filter); 2283 kn->kn_fop = NULL; 2284 knote_free(kn); 2285 } 2286 2287 static void 2288 knote_enqueue(struct knote *kn) 2289 { 2290 struct kqueue *kq = kn->kn_kq; 2291 2292 KQ_OWNED(kn->kn_kq); 2293 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2294 2295 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2296 kn->kn_status |= KN_QUEUED; 2297 kq->kq_count++; 2298 kqueue_wakeup(kq); 2299 } 2300 2301 static void 2302 knote_dequeue(struct knote *kn) 2303 { 2304 struct kqueue *kq = kn->kn_kq; 2305 2306 KQ_OWNED(kn->kn_kq); 2307 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2308 2309 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2310 kn->kn_status &= ~KN_QUEUED; 2311 kq->kq_count--; 2312 } 2313 2314 static void 2315 knote_init(void) 2316 { 2317 2318 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2319 NULL, NULL, UMA_ALIGN_PTR, 0); 2320 } 2321 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2322 2323 static struct knote * 2324 knote_alloc(int waitok) 2325 { 2326 return ((struct knote *)uma_zalloc(knote_zone, 2327 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2328 } 2329 2330 static void 2331 knote_free(struct knote *kn) 2332 { 2333 if (kn != NULL) 2334 uma_zfree(knote_zone, kn); 2335 } 2336 2337 /* 2338 * Register the kev w/ the kq specified by fd. 2339 */ 2340 int 2341 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2342 { 2343 struct kqueue *kq; 2344 struct file *fp; 2345 cap_rights_t rights; 2346 int error; 2347 2348 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2349 if (error != 0) 2350 return (error); 2351 if ((error = kqueue_acquire(fp, &kq)) != 0) 2352 goto noacquire; 2353 2354 error = kqueue_register(kq, kev, td, waitok); 2355 2356 kqueue_release(kq, 0); 2357 2358 noacquire: 2359 fdrop(fp, td); 2360 2361 return error; 2362 } 2363