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 #include <sys/user.h> 69 #ifdef KTRACE 70 #include <sys/ktrace.h> 71 #endif 72 73 #include <vm/uma.h> 74 75 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 76 77 /* 78 * This lock is used if multiple kq locks are required. This possibly 79 * should be made into a per proc lock. 80 */ 81 static struct mtx kq_global; 82 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 83 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 84 if (!haslck) \ 85 mtx_lock(lck); \ 86 haslck = 1; \ 87 } while (0) 88 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 89 if (haslck) \ 90 mtx_unlock(lck); \ 91 haslck = 0; \ 92 } while (0) 93 94 TASKQUEUE_DEFINE_THREAD(kqueue); 95 96 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 97 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 98 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 99 struct thread *td, int waitok); 100 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 101 static void kqueue_release(struct kqueue *kq, int locked); 102 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 103 uintptr_t ident, int waitok); 104 static void kqueue_task(void *arg, int pending); 105 static int kqueue_scan(struct kqueue *kq, int maxevents, 106 struct kevent_copyops *k_ops, 107 const struct timespec *timeout, 108 struct kevent *keva, struct thread *td); 109 static void kqueue_wakeup(struct kqueue *kq); 110 static struct filterops *kqueue_fo_find(int filt); 111 static void kqueue_fo_release(int filt); 112 113 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 static fo_fill_kinfo_t kqueue_fill_kinfo; 119 120 static struct fileops kqueueops = { 121 .fo_read = invfo_rdwr, 122 .fo_write = invfo_rdwr, 123 .fo_truncate = invfo_truncate, 124 .fo_ioctl = kqueue_ioctl, 125 .fo_poll = kqueue_poll, 126 .fo_kqfilter = kqueue_kqfilter, 127 .fo_stat = kqueue_stat, 128 .fo_close = kqueue_close, 129 .fo_chmod = invfo_chmod, 130 .fo_chown = invfo_chown, 131 .fo_sendfile = invfo_sendfile, 132 .fo_fill_kinfo = kqueue_fill_kinfo, 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_nolock; 285 int for_refcnt; 286 } sysfilt_ops[EVFILT_SYSCOUNT] = { 287 { &file_filtops, 1 }, /* EVFILT_READ */ 288 { &file_filtops, 1 }, /* EVFILT_WRITE */ 289 { &null_filtops }, /* EVFILT_AIO */ 290 { &file_filtops, 1 }, /* EVFILT_VNODE */ 291 { &proc_filtops, 1 }, /* EVFILT_PROC */ 292 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 293 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 294 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 295 { &fs_filtops, 1 }, /* EVFILT_FS */ 296 { &null_filtops }, /* EVFILT_LIO */ 297 { &user_filtops, 1 }, /* EVFILT_USER */ 298 { &null_filtops }, /* EVFILT_SENDFILE */ 299 }; 300 301 /* 302 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 303 * method. 304 */ 305 static int 306 filt_fileattach(struct knote *kn) 307 { 308 309 return (fo_kqfilter(kn->kn_fp, kn)); 310 } 311 312 /*ARGSUSED*/ 313 static int 314 kqueue_kqfilter(struct file *fp, struct knote *kn) 315 { 316 struct kqueue *kq = kn->kn_fp->f_data; 317 318 if (kn->kn_filter != EVFILT_READ) 319 return (EINVAL); 320 321 kn->kn_status |= KN_KQUEUE; 322 kn->kn_fop = &kqread_filtops; 323 knlist_add(&kq->kq_sel.si_note, kn, 0); 324 325 return (0); 326 } 327 328 static void 329 filt_kqdetach(struct knote *kn) 330 { 331 struct kqueue *kq = kn->kn_fp->f_data; 332 333 knlist_remove(&kq->kq_sel.si_note, kn, 0); 334 } 335 336 /*ARGSUSED*/ 337 static int 338 filt_kqueue(struct knote *kn, long hint) 339 { 340 struct kqueue *kq = kn->kn_fp->f_data; 341 342 kn->kn_data = kq->kq_count; 343 return (kn->kn_data > 0); 344 } 345 346 /* XXX - move to kern_proc.c? */ 347 static int 348 filt_procattach(struct knote *kn) 349 { 350 struct proc *p; 351 int immediate; 352 int error; 353 354 immediate = 0; 355 p = pfind(kn->kn_id); 356 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 357 p = zpfind(kn->kn_id); 358 immediate = 1; 359 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 360 immediate = 1; 361 } 362 363 if (p == NULL) 364 return (ESRCH); 365 if ((error = p_cansee(curthread, p))) { 366 PROC_UNLOCK(p); 367 return (error); 368 } 369 370 kn->kn_ptr.p_proc = p; 371 kn->kn_flags |= EV_CLEAR; /* automatically set */ 372 373 /* 374 * internal flag indicating registration done by kernel 375 */ 376 if (kn->kn_flags & EV_FLAG1) { 377 kn->kn_data = kn->kn_sdata; /* ppid */ 378 kn->kn_fflags = NOTE_CHILD; 379 kn->kn_flags &= ~EV_FLAG1; 380 } 381 382 if (immediate == 0) 383 knlist_add(&p->p_klist, kn, 1); 384 385 /* 386 * Immediately activate any exit notes if the target process is a 387 * zombie. This is necessary to handle the case where the target 388 * process, e.g. a child, dies before the kevent is registered. 389 */ 390 if (immediate && filt_proc(kn, NOTE_EXIT)) 391 KNOTE_ACTIVATE(kn, 0); 392 393 PROC_UNLOCK(p); 394 395 return (0); 396 } 397 398 /* 399 * The knote may be attached to a different process, which may exit, 400 * leaving nothing for the knote to be attached to. So when the process 401 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 402 * it will be deleted when read out. However, as part of the knote deletion, 403 * this routine is called, so a check is needed to avoid actually performing 404 * a detach, because the original process does not exist any more. 405 */ 406 /* XXX - move to kern_proc.c? */ 407 static void 408 filt_procdetach(struct knote *kn) 409 { 410 struct proc *p; 411 412 p = kn->kn_ptr.p_proc; 413 knlist_remove(&p->p_klist, kn, 0); 414 kn->kn_ptr.p_proc = NULL; 415 } 416 417 /* XXX - move to kern_proc.c? */ 418 static int 419 filt_proc(struct knote *kn, long hint) 420 { 421 struct proc *p; 422 u_int event; 423 424 p = kn->kn_ptr.p_proc; 425 /* Mask off extra data. */ 426 event = (u_int)hint & NOTE_PCTRLMASK; 427 428 /* If the user is interested in this event, record it. */ 429 if (kn->kn_sfflags & event) 430 kn->kn_fflags |= event; 431 432 /* Process is gone, so flag the event as finished. */ 433 if (event == NOTE_EXIT) { 434 if (!(kn->kn_status & KN_DETACHED)) 435 knlist_remove_inevent(&p->p_klist, kn); 436 kn->kn_flags |= EV_EOF | EV_ONESHOT; 437 kn->kn_ptr.p_proc = NULL; 438 if (kn->kn_fflags & NOTE_EXIT) 439 kn->kn_data = p->p_xstat; 440 if (kn->kn_fflags == 0) 441 kn->kn_flags |= EV_DROP; 442 return (1); 443 } 444 445 return (kn->kn_fflags != 0); 446 } 447 448 /* 449 * Called when the process forked. It mostly does the same as the 450 * knote(), activating all knotes registered to be activated when the 451 * process forked. Additionally, for each knote attached to the 452 * parent, check whether user wants to track the new process. If so 453 * attach a new knote to it, and immediately report an event with the 454 * child's pid. 455 */ 456 void 457 knote_fork(struct knlist *list, int pid) 458 { 459 struct kqueue *kq; 460 struct knote *kn; 461 struct kevent kev; 462 int error; 463 464 if (list == NULL) 465 return; 466 list->kl_lock(list->kl_lockarg); 467 468 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 469 /* 470 * XXX - Why do we skip the kn if it is _INFLUX? Does this 471 * mean we will not properly wake up some notes? 472 */ 473 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 474 continue; 475 kq = kn->kn_kq; 476 KQ_LOCK(kq); 477 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 478 KQ_UNLOCK(kq); 479 continue; 480 } 481 482 /* 483 * The same as knote(), activate the event. 484 */ 485 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 486 kn->kn_status |= KN_HASKQLOCK; 487 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 488 KNOTE_ACTIVATE(kn, 1); 489 kn->kn_status &= ~KN_HASKQLOCK; 490 KQ_UNLOCK(kq); 491 continue; 492 } 493 494 /* 495 * The NOTE_TRACK case. In addition to the activation 496 * of the event, we need to register new event to 497 * track the child. Drop the locks in preparation for 498 * the call to kqueue_register(). 499 */ 500 kn->kn_status |= KN_INFLUX; 501 KQ_UNLOCK(kq); 502 list->kl_unlock(list->kl_lockarg); 503 504 /* 505 * Activate existing knote and register a knote with 506 * new process. 507 */ 508 kev.ident = pid; 509 kev.filter = kn->kn_filter; 510 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 511 kev.fflags = kn->kn_sfflags; 512 kev.data = kn->kn_id; /* parent */ 513 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 514 error = kqueue_register(kq, &kev, NULL, 0); 515 if (error) 516 kn->kn_fflags |= NOTE_TRACKERR; 517 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 518 KNOTE_ACTIVATE(kn, 0); 519 KQ_LOCK(kq); 520 kn->kn_status &= ~KN_INFLUX; 521 KQ_UNLOCK_FLUX(kq); 522 list->kl_lock(list->kl_lockarg); 523 } 524 list->kl_unlock(list->kl_lockarg); 525 } 526 527 /* 528 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 529 * interval timer support code. 530 */ 531 532 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \ 533 NOTE_NSECONDS) 534 535 static __inline sbintime_t 536 timer2sbintime(intptr_t data, int flags) 537 { 538 sbintime_t modifier; 539 540 switch (flags & NOTE_TIMER_PRECMASK) { 541 case NOTE_SECONDS: 542 modifier = SBT_1S; 543 break; 544 case NOTE_MSECONDS: /* FALLTHROUGH */ 545 case 0: 546 modifier = SBT_1MS; 547 break; 548 case NOTE_USECONDS: 549 modifier = SBT_1US; 550 break; 551 case NOTE_NSECONDS: 552 modifier = SBT_1NS; 553 break; 554 default: 555 return (-1); 556 } 557 558 #ifdef __LP64__ 559 if (data > SBT_MAX / modifier) 560 return (SBT_MAX); 561 #endif 562 return (modifier * data); 563 } 564 565 static void 566 filt_timerexpire(void *knx) 567 { 568 struct callout *calloutp; 569 struct knote *kn; 570 571 kn = knx; 572 kn->kn_data++; 573 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 574 575 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 576 calloutp = (struct callout *)kn->kn_hook; 577 *kn->kn_ptr.p_nexttime += timer2sbintime(kn->kn_sdata, 578 kn->kn_sfflags); 579 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 580 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 581 } 582 } 583 584 /* 585 * data contains amount of time to sleep 586 */ 587 static int 588 filt_timerattach(struct knote *kn) 589 { 590 struct callout *calloutp; 591 sbintime_t to; 592 unsigned int ncallouts; 593 594 if ((intptr_t)kn->kn_sdata < 0) 595 return (EINVAL); 596 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 597 kn->kn_sdata = 1; 598 /* Only precision unit are supported in flags so far */ 599 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) 600 return (EINVAL); 601 602 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 603 if (to < 0) 604 return (EINVAL); 605 606 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 607 do { 608 if (ncallouts >= kq_calloutmax) 609 return (ENOMEM); 610 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 611 &ncallouts, ncallouts + 1, memory_order_relaxed, 612 memory_order_relaxed)); 613 614 kn->kn_flags |= EV_CLEAR; /* automatically set */ 615 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 616 kn->kn_ptr.p_nexttime = malloc(sizeof(sbintime_t), M_KQUEUE, M_WAITOK); 617 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 618 callout_init(calloutp, CALLOUT_MPSAFE); 619 kn->kn_hook = calloutp; 620 *kn->kn_ptr.p_nexttime = to + sbinuptime(); 621 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 622 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 623 624 return (0); 625 } 626 627 static void 628 filt_timerdetach(struct knote *kn) 629 { 630 struct callout *calloutp; 631 unsigned int old; 632 633 calloutp = (struct callout *)kn->kn_hook; 634 callout_drain(calloutp); 635 free(calloutp, M_KQUEUE); 636 free(kn->kn_ptr.p_nexttime, M_KQUEUE); 637 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 638 KASSERT(old > 0, ("Number of callouts cannot become negative")); 639 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 640 } 641 642 static int 643 filt_timer(struct knote *kn, long hint) 644 { 645 646 return (kn->kn_data != 0); 647 } 648 649 static int 650 filt_userattach(struct knote *kn) 651 { 652 653 /* 654 * EVFILT_USER knotes are not attached to anything in the kernel. 655 */ 656 kn->kn_hook = NULL; 657 if (kn->kn_fflags & NOTE_TRIGGER) 658 kn->kn_hookid = 1; 659 else 660 kn->kn_hookid = 0; 661 return (0); 662 } 663 664 static void 665 filt_userdetach(__unused struct knote *kn) 666 { 667 668 /* 669 * EVFILT_USER knotes are not attached to anything in the kernel. 670 */ 671 } 672 673 static int 674 filt_user(struct knote *kn, __unused long hint) 675 { 676 677 return (kn->kn_hookid); 678 } 679 680 static void 681 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 682 { 683 u_int ffctrl; 684 685 switch (type) { 686 case EVENT_REGISTER: 687 if (kev->fflags & NOTE_TRIGGER) 688 kn->kn_hookid = 1; 689 690 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 691 kev->fflags &= NOTE_FFLAGSMASK; 692 switch (ffctrl) { 693 case NOTE_FFNOP: 694 break; 695 696 case NOTE_FFAND: 697 kn->kn_sfflags &= kev->fflags; 698 break; 699 700 case NOTE_FFOR: 701 kn->kn_sfflags |= kev->fflags; 702 break; 703 704 case NOTE_FFCOPY: 705 kn->kn_sfflags = kev->fflags; 706 break; 707 708 default: 709 /* XXX Return error? */ 710 break; 711 } 712 kn->kn_sdata = kev->data; 713 if (kev->flags & EV_CLEAR) { 714 kn->kn_hookid = 0; 715 kn->kn_data = 0; 716 kn->kn_fflags = 0; 717 } 718 break; 719 720 case EVENT_PROCESS: 721 *kev = kn->kn_kevent; 722 kev->fflags = kn->kn_sfflags; 723 kev->data = kn->kn_sdata; 724 if (kn->kn_flags & EV_CLEAR) { 725 kn->kn_hookid = 0; 726 kn->kn_data = 0; 727 kn->kn_fflags = 0; 728 } 729 break; 730 731 default: 732 panic("filt_usertouch() - invalid type (%ld)", type); 733 break; 734 } 735 } 736 737 int 738 sys_kqueue(struct thread *td, struct kqueue_args *uap) 739 { 740 struct filedesc *fdp; 741 struct kqueue *kq; 742 struct file *fp; 743 struct proc *p; 744 struct ucred *cred; 745 int fd, error; 746 747 p = td->td_proc; 748 cred = td->td_ucred; 749 crhold(cred); 750 PROC_LOCK(p); 751 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 752 RLIMIT_KQUEUES))) { 753 PROC_UNLOCK(p); 754 crfree(cred); 755 return (ENOMEM); 756 } 757 PROC_UNLOCK(p); 758 759 fdp = p->p_fd; 760 error = falloc(td, &fp, &fd, 0); 761 if (error) 762 goto done2; 763 764 /* An extra reference on `fp' has been held for us by falloc(). */ 765 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 766 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 767 TAILQ_INIT(&kq->kq_head); 768 kq->kq_fdp = fdp; 769 kq->kq_cred = cred; 770 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 771 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 772 773 FILEDESC_XLOCK(fdp); 774 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 775 FILEDESC_XUNLOCK(fdp); 776 777 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 778 fdrop(fp, td); 779 780 td->td_retval[0] = fd; 781 done2: 782 if (error != 0) { 783 chgkqcnt(cred->cr_ruidinfo, -1, 0); 784 crfree(cred); 785 } 786 return (error); 787 } 788 789 #ifndef _SYS_SYSPROTO_H_ 790 struct kevent_args { 791 int fd; 792 const struct kevent *changelist; 793 int nchanges; 794 struct kevent *eventlist; 795 int nevents; 796 const struct timespec *timeout; 797 }; 798 #endif 799 int 800 sys_kevent(struct thread *td, struct kevent_args *uap) 801 { 802 struct timespec ts, *tsp; 803 struct kevent_copyops k_ops = { uap, 804 kevent_copyout, 805 kevent_copyin}; 806 int error; 807 #ifdef KTRACE 808 struct uio ktruio; 809 struct iovec ktriov; 810 struct uio *ktruioin = NULL; 811 struct uio *ktruioout = NULL; 812 #endif 813 814 if (uap->timeout != NULL) { 815 error = copyin(uap->timeout, &ts, sizeof(ts)); 816 if (error) 817 return (error); 818 tsp = &ts; 819 } else 820 tsp = NULL; 821 822 #ifdef KTRACE 823 if (KTRPOINT(td, KTR_GENIO)) { 824 ktriov.iov_base = uap->changelist; 825 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 826 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 827 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 828 .uio_td = td }; 829 ktruioin = cloneuio(&ktruio); 830 ktriov.iov_base = uap->eventlist; 831 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 832 ktruioout = cloneuio(&ktruio); 833 } 834 #endif 835 836 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 837 &k_ops, tsp); 838 839 #ifdef KTRACE 840 if (ktruioin != NULL) { 841 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 842 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 843 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 844 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 845 } 846 #endif 847 848 return (error); 849 } 850 851 /* 852 * Copy 'count' items into the destination list pointed to by uap->eventlist. 853 */ 854 static int 855 kevent_copyout(void *arg, struct kevent *kevp, int count) 856 { 857 struct kevent_args *uap; 858 int error; 859 860 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 861 uap = (struct kevent_args *)arg; 862 863 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 864 if (error == 0) 865 uap->eventlist += count; 866 return (error); 867 } 868 869 /* 870 * Copy 'count' items from the list pointed to by uap->changelist. 871 */ 872 static int 873 kevent_copyin(void *arg, struct kevent *kevp, int count) 874 { 875 struct kevent_args *uap; 876 int error; 877 878 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 879 uap = (struct kevent_args *)arg; 880 881 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 882 if (error == 0) 883 uap->changelist += count; 884 return (error); 885 } 886 887 int 888 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 889 struct kevent_copyops *k_ops, const struct timespec *timeout) 890 { 891 struct kevent keva[KQ_NEVENTS]; 892 struct kevent *kevp, *changes; 893 struct kqueue *kq; 894 struct file *fp; 895 cap_rights_t rights; 896 int i, n, nerrors, error; 897 898 cap_rights_init(&rights); 899 if (nchanges > 0) 900 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 901 if (nevents > 0) 902 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 903 error = fget(td, fd, &rights, &fp); 904 if (error != 0) 905 return (error); 906 907 error = kqueue_acquire(fp, &kq); 908 if (error != 0) 909 goto done_norel; 910 911 nerrors = 0; 912 913 while (nchanges > 0) { 914 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 915 error = k_ops->k_copyin(k_ops->arg, keva, n); 916 if (error) 917 goto done; 918 changes = keva; 919 for (i = 0; i < n; i++) { 920 kevp = &changes[i]; 921 if (!kevp->filter) 922 continue; 923 kevp->flags &= ~EV_SYSFLAGS; 924 error = kqueue_register(kq, kevp, td, 1); 925 if (error || (kevp->flags & EV_RECEIPT)) { 926 if (nevents != 0) { 927 kevp->flags = EV_ERROR; 928 kevp->data = error; 929 (void) k_ops->k_copyout(k_ops->arg, 930 kevp, 1); 931 nevents--; 932 nerrors++; 933 } else { 934 goto done; 935 } 936 } 937 } 938 nchanges -= n; 939 } 940 if (nerrors) { 941 td->td_retval[0] = nerrors; 942 error = 0; 943 goto done; 944 } 945 946 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 947 done: 948 kqueue_release(kq, 0); 949 done_norel: 950 fdrop(fp, td); 951 return (error); 952 } 953 954 int 955 kqueue_add_filteropts(int filt, struct filterops *filtops) 956 { 957 int error; 958 959 error = 0; 960 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 961 printf( 962 "trying to add a filterop that is out of range: %d is beyond %d\n", 963 ~filt, EVFILT_SYSCOUNT); 964 return EINVAL; 965 } 966 mtx_lock(&filterops_lock); 967 if (sysfilt_ops[~filt].for_fop != &null_filtops && 968 sysfilt_ops[~filt].for_fop != NULL) 969 error = EEXIST; 970 else { 971 sysfilt_ops[~filt].for_fop = filtops; 972 sysfilt_ops[~filt].for_refcnt = 0; 973 } 974 mtx_unlock(&filterops_lock); 975 976 return (error); 977 } 978 979 int 980 kqueue_del_filteropts(int filt) 981 { 982 int error; 983 984 error = 0; 985 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 986 return EINVAL; 987 988 mtx_lock(&filterops_lock); 989 if (sysfilt_ops[~filt].for_fop == &null_filtops || 990 sysfilt_ops[~filt].for_fop == NULL) 991 error = EINVAL; 992 else if (sysfilt_ops[~filt].for_refcnt != 0) 993 error = EBUSY; 994 else { 995 sysfilt_ops[~filt].for_fop = &null_filtops; 996 sysfilt_ops[~filt].for_refcnt = 0; 997 } 998 mtx_unlock(&filterops_lock); 999 1000 return error; 1001 } 1002 1003 static struct filterops * 1004 kqueue_fo_find(int filt) 1005 { 1006 1007 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1008 return NULL; 1009 1010 if (sysfilt_ops[~filt].for_nolock) 1011 return sysfilt_ops[~filt].for_fop; 1012 1013 mtx_lock(&filterops_lock); 1014 sysfilt_ops[~filt].for_refcnt++; 1015 if (sysfilt_ops[~filt].for_fop == NULL) 1016 sysfilt_ops[~filt].for_fop = &null_filtops; 1017 mtx_unlock(&filterops_lock); 1018 1019 return sysfilt_ops[~filt].for_fop; 1020 } 1021 1022 static void 1023 kqueue_fo_release(int filt) 1024 { 1025 1026 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1027 return; 1028 1029 if (sysfilt_ops[~filt].for_nolock) 1030 return; 1031 1032 mtx_lock(&filterops_lock); 1033 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1034 ("filter object refcount not valid on release")); 1035 sysfilt_ops[~filt].for_refcnt--; 1036 mtx_unlock(&filterops_lock); 1037 } 1038 1039 /* 1040 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1041 * influence if memory allocation should wait. Make sure it is 0 if you 1042 * hold any mutexes. 1043 */ 1044 static int 1045 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1046 { 1047 struct filterops *fops; 1048 struct file *fp; 1049 struct knote *kn, *tkn; 1050 cap_rights_t rights; 1051 int error, filt, event; 1052 int haskqglobal, filedesc_unlock; 1053 1054 fp = NULL; 1055 kn = NULL; 1056 error = 0; 1057 haskqglobal = 0; 1058 filedesc_unlock = 0; 1059 1060 filt = kev->filter; 1061 fops = kqueue_fo_find(filt); 1062 if (fops == NULL) 1063 return EINVAL; 1064 1065 if (kev->flags & EV_ADD) 1066 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1067 else 1068 tkn = NULL; 1069 1070 findkn: 1071 if (fops->f_isfd) { 1072 KASSERT(td != NULL, ("td is NULL")); 1073 error = fget(td, kev->ident, 1074 cap_rights_init(&rights, CAP_EVENT), &fp); 1075 if (error) 1076 goto done; 1077 1078 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1079 kev->ident, 0) != 0) { 1080 /* try again */ 1081 fdrop(fp, td); 1082 fp = NULL; 1083 error = kqueue_expand(kq, fops, kev->ident, waitok); 1084 if (error) 1085 goto done; 1086 goto findkn; 1087 } 1088 1089 if (fp->f_type == DTYPE_KQUEUE) { 1090 /* 1091 * if we add some inteligence about what we are doing, 1092 * we should be able to support events on ourselves. 1093 * We need to know when we are doing this to prevent 1094 * getting both the knlist lock and the kq lock since 1095 * they are the same thing. 1096 */ 1097 if (fp->f_data == kq) { 1098 error = EINVAL; 1099 goto done; 1100 } 1101 1102 /* 1103 * Pre-lock the filedesc before the global 1104 * lock mutex, see the comment in 1105 * kqueue_close(). 1106 */ 1107 FILEDESC_XLOCK(td->td_proc->p_fd); 1108 filedesc_unlock = 1; 1109 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1110 } 1111 1112 KQ_LOCK(kq); 1113 if (kev->ident < kq->kq_knlistsize) { 1114 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1115 if (kev->filter == kn->kn_filter) 1116 break; 1117 } 1118 } else { 1119 if ((kev->flags & EV_ADD) == EV_ADD) 1120 kqueue_expand(kq, fops, kev->ident, waitok); 1121 1122 KQ_LOCK(kq); 1123 if (kq->kq_knhashmask != 0) { 1124 struct klist *list; 1125 1126 list = &kq->kq_knhash[ 1127 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1128 SLIST_FOREACH(kn, list, kn_link) 1129 if (kev->ident == kn->kn_id && 1130 kev->filter == kn->kn_filter) 1131 break; 1132 } 1133 } 1134 1135 /* knote is in the process of changing, wait for it to stablize. */ 1136 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1137 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1138 if (filedesc_unlock) { 1139 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1140 filedesc_unlock = 0; 1141 } 1142 kq->kq_state |= KQ_FLUXWAIT; 1143 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1144 if (fp != NULL) { 1145 fdrop(fp, td); 1146 fp = NULL; 1147 } 1148 goto findkn; 1149 } 1150 1151 /* 1152 * kn now contains the matching knote, or NULL if no match 1153 */ 1154 if (kn == NULL) { 1155 if (kev->flags & EV_ADD) { 1156 kn = tkn; 1157 tkn = NULL; 1158 if (kn == NULL) { 1159 KQ_UNLOCK(kq); 1160 error = ENOMEM; 1161 goto done; 1162 } 1163 kn->kn_fp = fp; 1164 kn->kn_kq = kq; 1165 kn->kn_fop = fops; 1166 /* 1167 * apply reference counts to knote structure, and 1168 * do not release it at the end of this routine. 1169 */ 1170 fops = NULL; 1171 fp = NULL; 1172 1173 kn->kn_sfflags = kev->fflags; 1174 kn->kn_sdata = kev->data; 1175 kev->fflags = 0; 1176 kev->data = 0; 1177 kn->kn_kevent = *kev; 1178 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1179 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1180 kn->kn_status = KN_INFLUX|KN_DETACHED; 1181 1182 error = knote_attach(kn, kq); 1183 KQ_UNLOCK(kq); 1184 if (error != 0) { 1185 tkn = kn; 1186 goto done; 1187 } 1188 1189 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1190 knote_drop(kn, td); 1191 goto done; 1192 } 1193 KN_LIST_LOCK(kn); 1194 goto done_ev_add; 1195 } else { 1196 /* No matching knote and the EV_ADD flag is not set. */ 1197 KQ_UNLOCK(kq); 1198 error = ENOENT; 1199 goto done; 1200 } 1201 } 1202 1203 if (kev->flags & EV_DELETE) { 1204 kn->kn_status |= KN_INFLUX; 1205 KQ_UNLOCK(kq); 1206 if (!(kn->kn_status & KN_DETACHED)) 1207 kn->kn_fop->f_detach(kn); 1208 knote_drop(kn, td); 1209 goto done; 1210 } 1211 1212 if (kev->flags & EV_FORCEONESHOT) { 1213 kn->kn_flags |= EV_ONESHOT; 1214 KNOTE_ACTIVATE(kn, 1); 1215 } 1216 1217 /* 1218 * The user may change some filter values after the initial EV_ADD, 1219 * but doing so will not reset any filter which has already been 1220 * triggered. 1221 */ 1222 kn->kn_status |= KN_INFLUX | KN_SCAN; 1223 KQ_UNLOCK(kq); 1224 KN_LIST_LOCK(kn); 1225 kn->kn_kevent.udata = kev->udata; 1226 if (!fops->f_isfd && fops->f_touch != NULL) { 1227 fops->f_touch(kn, kev, EVENT_REGISTER); 1228 } else { 1229 kn->kn_sfflags = kev->fflags; 1230 kn->kn_sdata = kev->data; 1231 } 1232 1233 /* 1234 * We can get here with kn->kn_knlist == NULL. This can happen when 1235 * the initial attach event decides that the event is "completed" 1236 * already. i.e. filt_procattach is called on a zombie process. It 1237 * will call filt_proc which will remove it from the list, and NULL 1238 * kn_knlist. 1239 */ 1240 done_ev_add: 1241 if ((kev->flags & EV_DISABLE) && 1242 ((kn->kn_status & KN_DISABLED) == 0)) { 1243 kn->kn_status |= KN_DISABLED; 1244 } 1245 1246 if ((kn->kn_status & KN_DISABLED) == 0) 1247 event = kn->kn_fop->f_event(kn, 0); 1248 else 1249 event = 0; 1250 KQ_LOCK(kq); 1251 if (event) 1252 KNOTE_ACTIVATE(kn, 1); 1253 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1254 KN_LIST_UNLOCK(kn); 1255 1256 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1257 kn->kn_status &= ~KN_DISABLED; 1258 if ((kn->kn_status & KN_ACTIVE) && 1259 ((kn->kn_status & KN_QUEUED) == 0)) 1260 knote_enqueue(kn); 1261 } 1262 KQ_UNLOCK_FLUX(kq); 1263 1264 done: 1265 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1266 if (filedesc_unlock) 1267 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1268 if (fp != NULL) 1269 fdrop(fp, td); 1270 if (tkn != NULL) 1271 knote_free(tkn); 1272 if (fops != NULL) 1273 kqueue_fo_release(filt); 1274 return (error); 1275 } 1276 1277 static int 1278 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1279 { 1280 int error; 1281 struct kqueue *kq; 1282 1283 error = 0; 1284 1285 kq = fp->f_data; 1286 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1287 return (EBADF); 1288 *kqp = kq; 1289 KQ_LOCK(kq); 1290 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1291 KQ_UNLOCK(kq); 1292 return (EBADF); 1293 } 1294 kq->kq_refcnt++; 1295 KQ_UNLOCK(kq); 1296 1297 return error; 1298 } 1299 1300 static void 1301 kqueue_release(struct kqueue *kq, int locked) 1302 { 1303 if (locked) 1304 KQ_OWNED(kq); 1305 else 1306 KQ_LOCK(kq); 1307 kq->kq_refcnt--; 1308 if (kq->kq_refcnt == 1) 1309 wakeup(&kq->kq_refcnt); 1310 if (!locked) 1311 KQ_UNLOCK(kq); 1312 } 1313 1314 static void 1315 kqueue_schedtask(struct kqueue *kq) 1316 { 1317 1318 KQ_OWNED(kq); 1319 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1320 ("scheduling kqueue task while draining")); 1321 1322 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1323 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1324 kq->kq_state |= KQ_TASKSCHED; 1325 } 1326 } 1327 1328 /* 1329 * Expand the kq to make sure we have storage for fops/ident pair. 1330 * 1331 * Return 0 on success (or no work necessary), return errno on failure. 1332 * 1333 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1334 * If kqueue_register is called from a non-fd context, there usually/should 1335 * be no locks held. 1336 */ 1337 static int 1338 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1339 int waitok) 1340 { 1341 struct klist *list, *tmp_knhash, *to_free; 1342 u_long tmp_knhashmask; 1343 int size; 1344 int fd; 1345 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1346 1347 KQ_NOTOWNED(kq); 1348 1349 to_free = NULL; 1350 if (fops->f_isfd) { 1351 fd = ident; 1352 if (kq->kq_knlistsize <= fd) { 1353 size = kq->kq_knlistsize; 1354 while (size <= fd) 1355 size += KQEXTENT; 1356 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1357 if (list == NULL) 1358 return ENOMEM; 1359 KQ_LOCK(kq); 1360 if (kq->kq_knlistsize > fd) { 1361 to_free = list; 1362 list = NULL; 1363 } else { 1364 if (kq->kq_knlist != NULL) { 1365 bcopy(kq->kq_knlist, list, 1366 kq->kq_knlistsize * sizeof(*list)); 1367 to_free = kq->kq_knlist; 1368 kq->kq_knlist = NULL; 1369 } 1370 bzero((caddr_t)list + 1371 kq->kq_knlistsize * sizeof(*list), 1372 (size - kq->kq_knlistsize) * sizeof(*list)); 1373 kq->kq_knlistsize = size; 1374 kq->kq_knlist = list; 1375 } 1376 KQ_UNLOCK(kq); 1377 } 1378 } else { 1379 if (kq->kq_knhashmask == 0) { 1380 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1381 &tmp_knhashmask); 1382 if (tmp_knhash == NULL) 1383 return ENOMEM; 1384 KQ_LOCK(kq); 1385 if (kq->kq_knhashmask == 0) { 1386 kq->kq_knhash = tmp_knhash; 1387 kq->kq_knhashmask = tmp_knhashmask; 1388 } else { 1389 to_free = tmp_knhash; 1390 } 1391 KQ_UNLOCK(kq); 1392 } 1393 } 1394 free(to_free, M_KQUEUE); 1395 1396 KQ_NOTOWNED(kq); 1397 return 0; 1398 } 1399 1400 static void 1401 kqueue_task(void *arg, int pending) 1402 { 1403 struct kqueue *kq; 1404 int haskqglobal; 1405 1406 haskqglobal = 0; 1407 kq = arg; 1408 1409 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1410 KQ_LOCK(kq); 1411 1412 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1413 1414 kq->kq_state &= ~KQ_TASKSCHED; 1415 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1416 wakeup(&kq->kq_state); 1417 } 1418 KQ_UNLOCK(kq); 1419 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1420 } 1421 1422 /* 1423 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1424 * We treat KN_MARKER knotes as if they are INFLUX. 1425 */ 1426 static int 1427 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1428 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1429 { 1430 struct kevent *kevp; 1431 struct knote *kn, *marker; 1432 sbintime_t asbt, rsbt; 1433 int count, error, haskqglobal, influx, nkev, touch; 1434 1435 count = maxevents; 1436 nkev = 0; 1437 error = 0; 1438 haskqglobal = 0; 1439 1440 if (maxevents == 0) 1441 goto done_nl; 1442 1443 rsbt = 0; 1444 if (tsp != NULL) { 1445 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1446 tsp->tv_nsec >= 1000000000) { 1447 error = EINVAL; 1448 goto done_nl; 1449 } 1450 if (timespecisset(tsp)) { 1451 if (tsp->tv_sec <= INT32_MAX) { 1452 rsbt = tstosbt(*tsp); 1453 if (TIMESEL(&asbt, rsbt)) 1454 asbt += tc_tick_sbt; 1455 if (asbt <= SBT_MAX - rsbt) 1456 asbt += rsbt; 1457 else 1458 asbt = 0; 1459 rsbt >>= tc_precexp; 1460 } else 1461 asbt = 0; 1462 } else 1463 asbt = -1; 1464 } else 1465 asbt = 0; 1466 marker = knote_alloc(1); 1467 if (marker == NULL) { 1468 error = ENOMEM; 1469 goto done_nl; 1470 } 1471 marker->kn_status = KN_MARKER; 1472 KQ_LOCK(kq); 1473 1474 retry: 1475 kevp = keva; 1476 if (kq->kq_count == 0) { 1477 if (asbt == -1) { 1478 error = EWOULDBLOCK; 1479 } else { 1480 kq->kq_state |= KQ_SLEEP; 1481 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1482 "kqread", asbt, rsbt, C_ABSOLUTE); 1483 } 1484 if (error == 0) 1485 goto retry; 1486 /* don't restart after signals... */ 1487 if (error == ERESTART) 1488 error = EINTR; 1489 else if (error == EWOULDBLOCK) 1490 error = 0; 1491 goto done; 1492 } 1493 1494 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1495 influx = 0; 1496 while (count) { 1497 KQ_OWNED(kq); 1498 kn = TAILQ_FIRST(&kq->kq_head); 1499 1500 if ((kn->kn_status == KN_MARKER && kn != marker) || 1501 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1502 if (influx) { 1503 influx = 0; 1504 KQ_FLUX_WAKEUP(kq); 1505 } 1506 kq->kq_state |= KQ_FLUXWAIT; 1507 error = msleep(kq, &kq->kq_lock, PSOCK, 1508 "kqflxwt", 0); 1509 continue; 1510 } 1511 1512 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1513 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1514 kn->kn_status &= ~KN_QUEUED; 1515 kq->kq_count--; 1516 continue; 1517 } 1518 if (kn == marker) { 1519 KQ_FLUX_WAKEUP(kq); 1520 if (count == maxevents) 1521 goto retry; 1522 goto done; 1523 } 1524 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1525 ("KN_INFLUX set when not suppose to be")); 1526 1527 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1528 kn->kn_status &= ~KN_QUEUED; 1529 kn->kn_status |= KN_INFLUX; 1530 kq->kq_count--; 1531 KQ_UNLOCK(kq); 1532 /* 1533 * We don't need to lock the list since we've marked 1534 * it _INFLUX. 1535 */ 1536 if (!(kn->kn_status & KN_DETACHED)) 1537 kn->kn_fop->f_detach(kn); 1538 knote_drop(kn, td); 1539 KQ_LOCK(kq); 1540 continue; 1541 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1542 kn->kn_status &= ~KN_QUEUED; 1543 kn->kn_status |= KN_INFLUX; 1544 kq->kq_count--; 1545 KQ_UNLOCK(kq); 1546 /* 1547 * We don't need to lock the list since we've marked 1548 * it _INFLUX. 1549 */ 1550 *kevp = kn->kn_kevent; 1551 if (!(kn->kn_status & KN_DETACHED)) 1552 kn->kn_fop->f_detach(kn); 1553 knote_drop(kn, td); 1554 KQ_LOCK(kq); 1555 kn = NULL; 1556 } else { 1557 kn->kn_status |= KN_INFLUX | KN_SCAN; 1558 KQ_UNLOCK(kq); 1559 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1560 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1561 KN_LIST_LOCK(kn); 1562 if (kn->kn_fop->f_event(kn, 0) == 0) { 1563 KQ_LOCK(kq); 1564 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1565 kn->kn_status &= 1566 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1567 KN_SCAN); 1568 kq->kq_count--; 1569 KN_LIST_UNLOCK(kn); 1570 influx = 1; 1571 continue; 1572 } 1573 touch = (!kn->kn_fop->f_isfd && 1574 kn->kn_fop->f_touch != NULL); 1575 if (touch) 1576 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1577 else 1578 *kevp = kn->kn_kevent; 1579 KQ_LOCK(kq); 1580 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1581 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1582 /* 1583 * Manually clear knotes who weren't 1584 * 'touch'ed. 1585 */ 1586 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1587 kn->kn_data = 0; 1588 kn->kn_fflags = 0; 1589 } 1590 if (kn->kn_flags & EV_DISPATCH) 1591 kn->kn_status |= KN_DISABLED; 1592 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1593 kq->kq_count--; 1594 } else 1595 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1596 1597 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1598 KN_LIST_UNLOCK(kn); 1599 influx = 1; 1600 } 1601 1602 /* we are returning a copy to the user */ 1603 kevp++; 1604 nkev++; 1605 count--; 1606 1607 if (nkev == KQ_NEVENTS) { 1608 influx = 0; 1609 KQ_UNLOCK_FLUX(kq); 1610 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1611 nkev = 0; 1612 kevp = keva; 1613 KQ_LOCK(kq); 1614 if (error) 1615 break; 1616 } 1617 } 1618 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1619 done: 1620 KQ_OWNED(kq); 1621 KQ_UNLOCK_FLUX(kq); 1622 knote_free(marker); 1623 done_nl: 1624 KQ_NOTOWNED(kq); 1625 if (nkev != 0) 1626 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1627 td->td_retval[0] = maxevents - count; 1628 return (error); 1629 } 1630 1631 /*ARGSUSED*/ 1632 static int 1633 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1634 struct ucred *active_cred, struct thread *td) 1635 { 1636 /* 1637 * Enabling sigio causes two major problems: 1638 * 1) infinite recursion: 1639 * Synopsys: kevent is being used to track signals and have FIOASYNC 1640 * set. On receipt of a signal this will cause a kqueue to recurse 1641 * into itself over and over. Sending the sigio causes the kqueue 1642 * to become ready, which in turn posts sigio again, forever. 1643 * Solution: this can be solved by setting a flag in the kqueue that 1644 * we have a SIGIO in progress. 1645 * 2) locking problems: 1646 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1647 * us above the proc and pgrp locks. 1648 * Solution: Post a signal using an async mechanism, being sure to 1649 * record a generation count in the delivery so that we do not deliver 1650 * a signal to the wrong process. 1651 * 1652 * Note, these two mechanisms are somewhat mutually exclusive! 1653 */ 1654 #if 0 1655 struct kqueue *kq; 1656 1657 kq = fp->f_data; 1658 switch (cmd) { 1659 case FIOASYNC: 1660 if (*(int *)data) { 1661 kq->kq_state |= KQ_ASYNC; 1662 } else { 1663 kq->kq_state &= ~KQ_ASYNC; 1664 } 1665 return (0); 1666 1667 case FIOSETOWN: 1668 return (fsetown(*(int *)data, &kq->kq_sigio)); 1669 1670 case FIOGETOWN: 1671 *(int *)data = fgetown(&kq->kq_sigio); 1672 return (0); 1673 } 1674 #endif 1675 1676 return (ENOTTY); 1677 } 1678 1679 /*ARGSUSED*/ 1680 static int 1681 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1682 struct thread *td) 1683 { 1684 struct kqueue *kq; 1685 int revents = 0; 1686 int error; 1687 1688 if ((error = kqueue_acquire(fp, &kq))) 1689 return POLLERR; 1690 1691 KQ_LOCK(kq); 1692 if (events & (POLLIN | POLLRDNORM)) { 1693 if (kq->kq_count) { 1694 revents |= events & (POLLIN | POLLRDNORM); 1695 } else { 1696 selrecord(td, &kq->kq_sel); 1697 if (SEL_WAITING(&kq->kq_sel)) 1698 kq->kq_state |= KQ_SEL; 1699 } 1700 } 1701 kqueue_release(kq, 1); 1702 KQ_UNLOCK(kq); 1703 return (revents); 1704 } 1705 1706 /*ARGSUSED*/ 1707 static int 1708 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1709 struct thread *td) 1710 { 1711 1712 bzero((void *)st, sizeof *st); 1713 /* 1714 * We no longer return kq_count because the unlocked value is useless. 1715 * If you spent all this time getting the count, why not spend your 1716 * syscall better by calling kevent? 1717 * 1718 * XXX - This is needed for libc_r. 1719 */ 1720 st->st_mode = S_IFIFO; 1721 return (0); 1722 } 1723 1724 /*ARGSUSED*/ 1725 static int 1726 kqueue_close(struct file *fp, struct thread *td) 1727 { 1728 struct kqueue *kq = fp->f_data; 1729 struct filedesc *fdp; 1730 struct knote *kn; 1731 int i; 1732 int error; 1733 int filedesc_unlock; 1734 1735 if ((error = kqueue_acquire(fp, &kq))) 1736 return error; 1737 1738 filedesc_unlock = 0; 1739 KQ_LOCK(kq); 1740 1741 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1742 ("kqueue already closing")); 1743 kq->kq_state |= KQ_CLOSING; 1744 if (kq->kq_refcnt > 1) 1745 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1746 1747 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1748 fdp = kq->kq_fdp; 1749 1750 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1751 ("kqueue's knlist not empty")); 1752 1753 for (i = 0; i < kq->kq_knlistsize; i++) { 1754 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1755 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1756 kq->kq_state |= KQ_FLUXWAIT; 1757 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1758 continue; 1759 } 1760 kn->kn_status |= KN_INFLUX; 1761 KQ_UNLOCK(kq); 1762 if (!(kn->kn_status & KN_DETACHED)) 1763 kn->kn_fop->f_detach(kn); 1764 knote_drop(kn, td); 1765 KQ_LOCK(kq); 1766 } 1767 } 1768 if (kq->kq_knhashmask != 0) { 1769 for (i = 0; i <= kq->kq_knhashmask; i++) { 1770 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1771 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1772 kq->kq_state |= KQ_FLUXWAIT; 1773 msleep(kq, &kq->kq_lock, PSOCK, 1774 "kqclo2", 0); 1775 continue; 1776 } 1777 kn->kn_status |= KN_INFLUX; 1778 KQ_UNLOCK(kq); 1779 if (!(kn->kn_status & KN_DETACHED)) 1780 kn->kn_fop->f_detach(kn); 1781 knote_drop(kn, td); 1782 KQ_LOCK(kq); 1783 } 1784 } 1785 } 1786 1787 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1788 kq->kq_state |= KQ_TASKDRAIN; 1789 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1790 } 1791 1792 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1793 selwakeuppri(&kq->kq_sel, PSOCK); 1794 if (!SEL_WAITING(&kq->kq_sel)) 1795 kq->kq_state &= ~KQ_SEL; 1796 } 1797 1798 KQ_UNLOCK(kq); 1799 1800 /* 1801 * We could be called due to the knote_drop() doing fdrop(), 1802 * called from kqueue_register(). In this case the global 1803 * lock is owned, and filedesc sx is locked before, to not 1804 * take the sleepable lock after non-sleepable. 1805 */ 1806 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1807 FILEDESC_XLOCK(fdp); 1808 filedesc_unlock = 1; 1809 } else 1810 filedesc_unlock = 0; 1811 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1812 if (filedesc_unlock) 1813 FILEDESC_XUNLOCK(fdp); 1814 1815 seldrain(&kq->kq_sel); 1816 knlist_destroy(&kq->kq_sel.si_note); 1817 mtx_destroy(&kq->kq_lock); 1818 kq->kq_fdp = NULL; 1819 1820 if (kq->kq_knhash != NULL) 1821 free(kq->kq_knhash, M_KQUEUE); 1822 if (kq->kq_knlist != NULL) 1823 free(kq->kq_knlist, M_KQUEUE); 1824 1825 funsetown(&kq->kq_sigio); 1826 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1827 crfree(kq->kq_cred); 1828 free(kq, M_KQUEUE); 1829 fp->f_data = NULL; 1830 1831 return (0); 1832 } 1833 1834 static int 1835 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 1836 { 1837 1838 kif->kf_type = KF_TYPE_KQUEUE; 1839 return (0); 1840 } 1841 1842 static void 1843 kqueue_wakeup(struct kqueue *kq) 1844 { 1845 KQ_OWNED(kq); 1846 1847 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1848 kq->kq_state &= ~KQ_SLEEP; 1849 wakeup(kq); 1850 } 1851 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1852 selwakeuppri(&kq->kq_sel, PSOCK); 1853 if (!SEL_WAITING(&kq->kq_sel)) 1854 kq->kq_state &= ~KQ_SEL; 1855 } 1856 if (!knlist_empty(&kq->kq_sel.si_note)) 1857 kqueue_schedtask(kq); 1858 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1859 pgsigio(&kq->kq_sigio, SIGIO, 0); 1860 } 1861 } 1862 1863 /* 1864 * Walk down a list of knotes, activating them if their event has triggered. 1865 * 1866 * There is a possibility to optimize in the case of one kq watching another. 1867 * Instead of scheduling a task to wake it up, you could pass enough state 1868 * down the chain to make up the parent kqueue. Make this code functional 1869 * first. 1870 */ 1871 void 1872 knote(struct knlist *list, long hint, int lockflags) 1873 { 1874 struct kqueue *kq; 1875 struct knote *kn; 1876 int error; 1877 1878 if (list == NULL) 1879 return; 1880 1881 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1882 1883 if ((lockflags & KNF_LISTLOCKED) == 0) 1884 list->kl_lock(list->kl_lockarg); 1885 1886 /* 1887 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1888 * the kqueue scheduling, but this will introduce four 1889 * lock/unlock's for each knote to test. If we do, continue to use 1890 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1891 * only safe if you want to remove the current item, which we are 1892 * not doing. 1893 */ 1894 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1895 kq = kn->kn_kq; 1896 KQ_LOCK(kq); 1897 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1898 /* 1899 * Do not process the influx notes, except for 1900 * the influx coming from the kq unlock in the 1901 * kqueue_scan(). In the later case, we do 1902 * not interfere with the scan, since the code 1903 * fragment in kqueue_scan() locks the knlist, 1904 * and cannot proceed until we finished. 1905 */ 1906 KQ_UNLOCK(kq); 1907 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1908 kn->kn_status |= KN_INFLUX; 1909 KQ_UNLOCK(kq); 1910 error = kn->kn_fop->f_event(kn, hint); 1911 KQ_LOCK(kq); 1912 kn->kn_status &= ~KN_INFLUX; 1913 if (error) 1914 KNOTE_ACTIVATE(kn, 1); 1915 KQ_UNLOCK_FLUX(kq); 1916 } else { 1917 kn->kn_status |= KN_HASKQLOCK; 1918 if (kn->kn_fop->f_event(kn, hint)) 1919 KNOTE_ACTIVATE(kn, 1); 1920 kn->kn_status &= ~KN_HASKQLOCK; 1921 KQ_UNLOCK(kq); 1922 } 1923 } 1924 if ((lockflags & KNF_LISTLOCKED) == 0) 1925 list->kl_unlock(list->kl_lockarg); 1926 } 1927 1928 /* 1929 * add a knote to a knlist 1930 */ 1931 void 1932 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1933 { 1934 KNL_ASSERT_LOCK(knl, islocked); 1935 KQ_NOTOWNED(kn->kn_kq); 1936 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1937 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1938 if (!islocked) 1939 knl->kl_lock(knl->kl_lockarg); 1940 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1941 if (!islocked) 1942 knl->kl_unlock(knl->kl_lockarg); 1943 KQ_LOCK(kn->kn_kq); 1944 kn->kn_knlist = knl; 1945 kn->kn_status &= ~KN_DETACHED; 1946 KQ_UNLOCK(kn->kn_kq); 1947 } 1948 1949 static void 1950 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1951 { 1952 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1953 KNL_ASSERT_LOCK(knl, knlislocked); 1954 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1955 if (!kqislocked) 1956 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1957 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1958 if (!knlislocked) 1959 knl->kl_lock(knl->kl_lockarg); 1960 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1961 kn->kn_knlist = NULL; 1962 if (!knlislocked) 1963 knl->kl_unlock(knl->kl_lockarg); 1964 if (!kqislocked) 1965 KQ_LOCK(kn->kn_kq); 1966 kn->kn_status |= KN_DETACHED; 1967 if (!kqislocked) 1968 KQ_UNLOCK(kn->kn_kq); 1969 } 1970 1971 /* 1972 * remove knote from the specified knlist 1973 */ 1974 void 1975 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1976 { 1977 1978 knlist_remove_kq(knl, kn, islocked, 0); 1979 } 1980 1981 /* 1982 * remove knote from the specified knlist while in f_event handler. 1983 */ 1984 void 1985 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1986 { 1987 1988 knlist_remove_kq(knl, kn, 1, 1989 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1990 } 1991 1992 int 1993 knlist_empty(struct knlist *knl) 1994 { 1995 1996 KNL_ASSERT_LOCKED(knl); 1997 return SLIST_EMPTY(&knl->kl_list); 1998 } 1999 2000 static struct mtx knlist_lock; 2001 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2002 MTX_DEF); 2003 static void knlist_mtx_lock(void *arg); 2004 static void knlist_mtx_unlock(void *arg); 2005 2006 static void 2007 knlist_mtx_lock(void *arg) 2008 { 2009 2010 mtx_lock((struct mtx *)arg); 2011 } 2012 2013 static void 2014 knlist_mtx_unlock(void *arg) 2015 { 2016 2017 mtx_unlock((struct mtx *)arg); 2018 } 2019 2020 static void 2021 knlist_mtx_assert_locked(void *arg) 2022 { 2023 2024 mtx_assert((struct mtx *)arg, MA_OWNED); 2025 } 2026 2027 static void 2028 knlist_mtx_assert_unlocked(void *arg) 2029 { 2030 2031 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2032 } 2033 2034 static void 2035 knlist_rw_rlock(void *arg) 2036 { 2037 2038 rw_rlock((struct rwlock *)arg); 2039 } 2040 2041 static void 2042 knlist_rw_runlock(void *arg) 2043 { 2044 2045 rw_runlock((struct rwlock *)arg); 2046 } 2047 2048 static void 2049 knlist_rw_assert_locked(void *arg) 2050 { 2051 2052 rw_assert((struct rwlock *)arg, RA_LOCKED); 2053 } 2054 2055 static void 2056 knlist_rw_assert_unlocked(void *arg) 2057 { 2058 2059 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2060 } 2061 2062 void 2063 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2064 void (*kl_unlock)(void *), 2065 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2066 { 2067 2068 if (lock == NULL) 2069 knl->kl_lockarg = &knlist_lock; 2070 else 2071 knl->kl_lockarg = lock; 2072 2073 if (kl_lock == NULL) 2074 knl->kl_lock = knlist_mtx_lock; 2075 else 2076 knl->kl_lock = kl_lock; 2077 if (kl_unlock == NULL) 2078 knl->kl_unlock = knlist_mtx_unlock; 2079 else 2080 knl->kl_unlock = kl_unlock; 2081 if (kl_assert_locked == NULL) 2082 knl->kl_assert_locked = knlist_mtx_assert_locked; 2083 else 2084 knl->kl_assert_locked = kl_assert_locked; 2085 if (kl_assert_unlocked == NULL) 2086 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2087 else 2088 knl->kl_assert_unlocked = kl_assert_unlocked; 2089 2090 SLIST_INIT(&knl->kl_list); 2091 } 2092 2093 void 2094 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2095 { 2096 2097 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2098 } 2099 2100 void 2101 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2102 { 2103 2104 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2105 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2106 } 2107 2108 void 2109 knlist_destroy(struct knlist *knl) 2110 { 2111 2112 #ifdef INVARIANTS 2113 /* 2114 * if we run across this error, we need to find the offending 2115 * driver and have it call knlist_clear or knlist_delete. 2116 */ 2117 if (!SLIST_EMPTY(&knl->kl_list)) 2118 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2119 #endif 2120 2121 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2122 SLIST_INIT(&knl->kl_list); 2123 } 2124 2125 /* 2126 * Even if we are locked, we may need to drop the lock to allow any influx 2127 * knotes time to "settle". 2128 */ 2129 void 2130 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2131 { 2132 struct knote *kn, *kn2; 2133 struct kqueue *kq; 2134 2135 if (islocked) 2136 KNL_ASSERT_LOCKED(knl); 2137 else { 2138 KNL_ASSERT_UNLOCKED(knl); 2139 again: /* need to reacquire lock since we have dropped it */ 2140 knl->kl_lock(knl->kl_lockarg); 2141 } 2142 2143 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2144 kq = kn->kn_kq; 2145 KQ_LOCK(kq); 2146 if ((kn->kn_status & KN_INFLUX)) { 2147 KQ_UNLOCK(kq); 2148 continue; 2149 } 2150 knlist_remove_kq(knl, kn, 1, 1); 2151 if (killkn) { 2152 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2153 KQ_UNLOCK(kq); 2154 knote_drop(kn, td); 2155 } else { 2156 /* Make sure cleared knotes disappear soon */ 2157 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2158 KQ_UNLOCK(kq); 2159 } 2160 kq = NULL; 2161 } 2162 2163 if (!SLIST_EMPTY(&knl->kl_list)) { 2164 /* there are still KN_INFLUX remaining */ 2165 kn = SLIST_FIRST(&knl->kl_list); 2166 kq = kn->kn_kq; 2167 KQ_LOCK(kq); 2168 KASSERT(kn->kn_status & KN_INFLUX, 2169 ("knote removed w/o list lock")); 2170 knl->kl_unlock(knl->kl_lockarg); 2171 kq->kq_state |= KQ_FLUXWAIT; 2172 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2173 kq = NULL; 2174 goto again; 2175 } 2176 2177 if (islocked) 2178 KNL_ASSERT_LOCKED(knl); 2179 else { 2180 knl->kl_unlock(knl->kl_lockarg); 2181 KNL_ASSERT_UNLOCKED(knl); 2182 } 2183 } 2184 2185 /* 2186 * Remove all knotes referencing a specified fd must be called with FILEDESC 2187 * lock. This prevents a race where a new fd comes along and occupies the 2188 * entry and we attach a knote to the fd. 2189 */ 2190 void 2191 knote_fdclose(struct thread *td, int fd) 2192 { 2193 struct filedesc *fdp = td->td_proc->p_fd; 2194 struct kqueue *kq; 2195 struct knote *kn; 2196 int influx; 2197 2198 FILEDESC_XLOCK_ASSERT(fdp); 2199 2200 /* 2201 * We shouldn't have to worry about new kevents appearing on fd 2202 * since filedesc is locked. 2203 */ 2204 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2205 KQ_LOCK(kq); 2206 2207 again: 2208 influx = 0; 2209 while (kq->kq_knlistsize > fd && 2210 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2211 if (kn->kn_status & KN_INFLUX) { 2212 /* someone else might be waiting on our knote */ 2213 if (influx) 2214 wakeup(kq); 2215 kq->kq_state |= KQ_FLUXWAIT; 2216 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2217 goto again; 2218 } 2219 kn->kn_status |= KN_INFLUX; 2220 KQ_UNLOCK(kq); 2221 if (!(kn->kn_status & KN_DETACHED)) 2222 kn->kn_fop->f_detach(kn); 2223 knote_drop(kn, td); 2224 influx = 1; 2225 KQ_LOCK(kq); 2226 } 2227 KQ_UNLOCK_FLUX(kq); 2228 } 2229 } 2230 2231 static int 2232 knote_attach(struct knote *kn, struct kqueue *kq) 2233 { 2234 struct klist *list; 2235 2236 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2237 KQ_OWNED(kq); 2238 2239 if (kn->kn_fop->f_isfd) { 2240 if (kn->kn_id >= kq->kq_knlistsize) 2241 return ENOMEM; 2242 list = &kq->kq_knlist[kn->kn_id]; 2243 } else { 2244 if (kq->kq_knhash == NULL) 2245 return ENOMEM; 2246 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2247 } 2248 2249 SLIST_INSERT_HEAD(list, kn, kn_link); 2250 2251 return 0; 2252 } 2253 2254 /* 2255 * knote must already have been detached using the f_detach method. 2256 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2257 * to prevent other removal. 2258 */ 2259 static void 2260 knote_drop(struct knote *kn, struct thread *td) 2261 { 2262 struct kqueue *kq; 2263 struct klist *list; 2264 2265 kq = kn->kn_kq; 2266 2267 KQ_NOTOWNED(kq); 2268 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2269 ("knote_drop called without KN_INFLUX set in kn_status")); 2270 2271 KQ_LOCK(kq); 2272 if (kn->kn_fop->f_isfd) 2273 list = &kq->kq_knlist[kn->kn_id]; 2274 else 2275 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2276 2277 if (!SLIST_EMPTY(list)) 2278 SLIST_REMOVE(list, kn, knote, kn_link); 2279 if (kn->kn_status & KN_QUEUED) 2280 knote_dequeue(kn); 2281 KQ_UNLOCK_FLUX(kq); 2282 2283 if (kn->kn_fop->f_isfd) { 2284 fdrop(kn->kn_fp, td); 2285 kn->kn_fp = NULL; 2286 } 2287 kqueue_fo_release(kn->kn_kevent.filter); 2288 kn->kn_fop = NULL; 2289 knote_free(kn); 2290 } 2291 2292 static void 2293 knote_enqueue(struct knote *kn) 2294 { 2295 struct kqueue *kq = kn->kn_kq; 2296 2297 KQ_OWNED(kn->kn_kq); 2298 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2299 2300 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2301 kn->kn_status |= KN_QUEUED; 2302 kq->kq_count++; 2303 kqueue_wakeup(kq); 2304 } 2305 2306 static void 2307 knote_dequeue(struct knote *kn) 2308 { 2309 struct kqueue *kq = kn->kn_kq; 2310 2311 KQ_OWNED(kn->kn_kq); 2312 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2313 2314 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2315 kn->kn_status &= ~KN_QUEUED; 2316 kq->kq_count--; 2317 } 2318 2319 static void 2320 knote_init(void) 2321 { 2322 2323 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2324 NULL, NULL, UMA_ALIGN_PTR, 0); 2325 } 2326 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2327 2328 static struct knote * 2329 knote_alloc(int waitok) 2330 { 2331 return ((struct knote *)uma_zalloc(knote_zone, 2332 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2333 } 2334 2335 static void 2336 knote_free(struct knote *kn) 2337 { 2338 if (kn != NULL) 2339 uma_zfree(knote_zone, kn); 2340 } 2341 2342 /* 2343 * Register the kev w/ the kq specified by fd. 2344 */ 2345 int 2346 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2347 { 2348 struct kqueue *kq; 2349 struct file *fp; 2350 cap_rights_t rights; 2351 int error; 2352 2353 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2354 if (error != 0) 2355 return (error); 2356 if ((error = kqueue_acquire(fp, &kq)) != 0) 2357 goto noacquire; 2358 2359 error = kqueue_register(kq, kev, td, waitok); 2360 2361 kqueue_release(kq, 0); 2362 2363 noacquire: 2364 fdrop(fp, td); 2365 2366 return error; 2367 } 2368