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, 1); 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 { 740 741 return (kern_kqueue(td, 0)); 742 } 743 744 int 745 kern_kqueue(struct thread *td, int flags) 746 { 747 struct filedesc *fdp; 748 struct kqueue *kq; 749 struct file *fp; 750 struct proc *p; 751 struct ucred *cred; 752 int fd, error; 753 754 p = td->td_proc; 755 cred = td->td_ucred; 756 crhold(cred); 757 PROC_LOCK(p); 758 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 759 RLIMIT_KQUEUES))) { 760 PROC_UNLOCK(p); 761 crfree(cred); 762 return (ENOMEM); 763 } 764 PROC_UNLOCK(p); 765 766 fdp = p->p_fd; 767 error = falloc(td, &fp, &fd, flags); 768 if (error) 769 goto done2; 770 771 /* An extra reference on `fp' has been held for us by falloc(). */ 772 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 773 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 774 TAILQ_INIT(&kq->kq_head); 775 kq->kq_fdp = fdp; 776 kq->kq_cred = cred; 777 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 778 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 779 780 FILEDESC_XLOCK(fdp); 781 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 782 FILEDESC_XUNLOCK(fdp); 783 784 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 785 fdrop(fp, td); 786 787 td->td_retval[0] = fd; 788 done2: 789 if (error != 0) { 790 chgkqcnt(cred->cr_ruidinfo, -1, 0); 791 crfree(cred); 792 } 793 return (error); 794 } 795 796 #ifndef _SYS_SYSPROTO_H_ 797 struct kevent_args { 798 int fd; 799 const struct kevent *changelist; 800 int nchanges; 801 struct kevent *eventlist; 802 int nevents; 803 const struct timespec *timeout; 804 }; 805 #endif 806 int 807 sys_kevent(struct thread *td, struct kevent_args *uap) 808 { 809 struct timespec ts, *tsp; 810 struct kevent_copyops k_ops = { uap, 811 kevent_copyout, 812 kevent_copyin}; 813 int error; 814 #ifdef KTRACE 815 struct uio ktruio; 816 struct iovec ktriov; 817 struct uio *ktruioin = NULL; 818 struct uio *ktruioout = NULL; 819 #endif 820 821 if (uap->timeout != NULL) { 822 error = copyin(uap->timeout, &ts, sizeof(ts)); 823 if (error) 824 return (error); 825 tsp = &ts; 826 } else 827 tsp = NULL; 828 829 #ifdef KTRACE 830 if (KTRPOINT(td, KTR_GENIO)) { 831 ktriov.iov_base = uap->changelist; 832 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 833 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 834 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 835 .uio_td = td }; 836 ktruioin = cloneuio(&ktruio); 837 ktriov.iov_base = uap->eventlist; 838 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 839 ktruioout = cloneuio(&ktruio); 840 } 841 #endif 842 843 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 844 &k_ops, tsp); 845 846 #ifdef KTRACE 847 if (ktruioin != NULL) { 848 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 849 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 850 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 851 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 852 } 853 #endif 854 855 return (error); 856 } 857 858 /* 859 * Copy 'count' items into the destination list pointed to by uap->eventlist. 860 */ 861 static int 862 kevent_copyout(void *arg, struct kevent *kevp, int count) 863 { 864 struct kevent_args *uap; 865 int error; 866 867 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 868 uap = (struct kevent_args *)arg; 869 870 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 871 if (error == 0) 872 uap->eventlist += count; 873 return (error); 874 } 875 876 /* 877 * Copy 'count' items from the list pointed to by uap->changelist. 878 */ 879 static int 880 kevent_copyin(void *arg, struct kevent *kevp, int count) 881 { 882 struct kevent_args *uap; 883 int error; 884 885 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 886 uap = (struct kevent_args *)arg; 887 888 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 889 if (error == 0) 890 uap->changelist += count; 891 return (error); 892 } 893 894 int 895 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 896 struct kevent_copyops *k_ops, const struct timespec *timeout) 897 { 898 cap_rights_t rights; 899 struct file *fp; 900 int error; 901 902 cap_rights_init(&rights); 903 if (nchanges > 0) 904 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 905 if (nevents > 0) 906 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 907 error = fget(td, fd, &rights, &fp); 908 if (error != 0) 909 return (error); 910 911 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 912 fdrop(fp, td); 913 914 return (error); 915 } 916 917 int 918 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 919 struct kevent_copyops *k_ops, const struct timespec *timeout) 920 { 921 struct kevent keva[KQ_NEVENTS]; 922 struct kevent *kevp, *changes; 923 struct kqueue *kq; 924 int i, n, nerrors, error; 925 926 error = kqueue_acquire(fp, &kq); 927 if (error != 0) 928 return (error); 929 930 nerrors = 0; 931 932 while (nchanges > 0) { 933 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 934 error = k_ops->k_copyin(k_ops->arg, keva, n); 935 if (error) 936 goto done; 937 changes = keva; 938 for (i = 0; i < n; i++) { 939 kevp = &changes[i]; 940 if (!kevp->filter) 941 continue; 942 kevp->flags &= ~EV_SYSFLAGS; 943 error = kqueue_register(kq, kevp, td, 1); 944 if (error || (kevp->flags & EV_RECEIPT)) { 945 if (nevents != 0) { 946 kevp->flags = EV_ERROR; 947 kevp->data = error; 948 (void) k_ops->k_copyout(k_ops->arg, 949 kevp, 1); 950 nevents--; 951 nerrors++; 952 } else { 953 goto done; 954 } 955 } 956 } 957 nchanges -= n; 958 } 959 if (nerrors) { 960 td->td_retval[0] = nerrors; 961 error = 0; 962 goto done; 963 } 964 965 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 966 done: 967 kqueue_release(kq, 0); 968 return (error); 969 } 970 971 int 972 kqueue_add_filteropts(int filt, struct filterops *filtops) 973 { 974 int error; 975 976 error = 0; 977 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 978 printf( 979 "trying to add a filterop that is out of range: %d is beyond %d\n", 980 ~filt, EVFILT_SYSCOUNT); 981 return EINVAL; 982 } 983 mtx_lock(&filterops_lock); 984 if (sysfilt_ops[~filt].for_fop != &null_filtops && 985 sysfilt_ops[~filt].for_fop != NULL) 986 error = EEXIST; 987 else { 988 sysfilt_ops[~filt].for_fop = filtops; 989 sysfilt_ops[~filt].for_refcnt = 0; 990 } 991 mtx_unlock(&filterops_lock); 992 993 return (error); 994 } 995 996 int 997 kqueue_del_filteropts(int filt) 998 { 999 int error; 1000 1001 error = 0; 1002 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1003 return EINVAL; 1004 1005 mtx_lock(&filterops_lock); 1006 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1007 sysfilt_ops[~filt].for_fop == NULL) 1008 error = EINVAL; 1009 else if (sysfilt_ops[~filt].for_refcnt != 0) 1010 error = EBUSY; 1011 else { 1012 sysfilt_ops[~filt].for_fop = &null_filtops; 1013 sysfilt_ops[~filt].for_refcnt = 0; 1014 } 1015 mtx_unlock(&filterops_lock); 1016 1017 return error; 1018 } 1019 1020 static struct filterops * 1021 kqueue_fo_find(int filt) 1022 { 1023 1024 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1025 return NULL; 1026 1027 if (sysfilt_ops[~filt].for_nolock) 1028 return sysfilt_ops[~filt].for_fop; 1029 1030 mtx_lock(&filterops_lock); 1031 sysfilt_ops[~filt].for_refcnt++; 1032 if (sysfilt_ops[~filt].for_fop == NULL) 1033 sysfilt_ops[~filt].for_fop = &null_filtops; 1034 mtx_unlock(&filterops_lock); 1035 1036 return sysfilt_ops[~filt].for_fop; 1037 } 1038 1039 static void 1040 kqueue_fo_release(int filt) 1041 { 1042 1043 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1044 return; 1045 1046 if (sysfilt_ops[~filt].for_nolock) 1047 return; 1048 1049 mtx_lock(&filterops_lock); 1050 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1051 ("filter object refcount not valid on release")); 1052 sysfilt_ops[~filt].for_refcnt--; 1053 mtx_unlock(&filterops_lock); 1054 } 1055 1056 /* 1057 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1058 * influence if memory allocation should wait. Make sure it is 0 if you 1059 * hold any mutexes. 1060 */ 1061 static int 1062 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1063 { 1064 struct filterops *fops; 1065 struct file *fp; 1066 struct knote *kn, *tkn; 1067 cap_rights_t rights; 1068 int error, filt, event; 1069 int haskqglobal, filedesc_unlock; 1070 1071 fp = NULL; 1072 kn = NULL; 1073 error = 0; 1074 haskqglobal = 0; 1075 filedesc_unlock = 0; 1076 1077 filt = kev->filter; 1078 fops = kqueue_fo_find(filt); 1079 if (fops == NULL) 1080 return EINVAL; 1081 1082 if (kev->flags & EV_ADD) 1083 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1084 else 1085 tkn = NULL; 1086 1087 findkn: 1088 if (fops->f_isfd) { 1089 KASSERT(td != NULL, ("td is NULL")); 1090 error = fget(td, kev->ident, 1091 cap_rights_init(&rights, CAP_EVENT), &fp); 1092 if (error) 1093 goto done; 1094 1095 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1096 kev->ident, 0) != 0) { 1097 /* try again */ 1098 fdrop(fp, td); 1099 fp = NULL; 1100 error = kqueue_expand(kq, fops, kev->ident, waitok); 1101 if (error) 1102 goto done; 1103 goto findkn; 1104 } 1105 1106 if (fp->f_type == DTYPE_KQUEUE) { 1107 /* 1108 * if we add some inteligence about what we are doing, 1109 * we should be able to support events on ourselves. 1110 * We need to know when we are doing this to prevent 1111 * getting both the knlist lock and the kq lock since 1112 * they are the same thing. 1113 */ 1114 if (fp->f_data == kq) { 1115 error = EINVAL; 1116 goto done; 1117 } 1118 1119 /* 1120 * Pre-lock the filedesc before the global 1121 * lock mutex, see the comment in 1122 * kqueue_close(). 1123 */ 1124 FILEDESC_XLOCK(td->td_proc->p_fd); 1125 filedesc_unlock = 1; 1126 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1127 } 1128 1129 KQ_LOCK(kq); 1130 if (kev->ident < kq->kq_knlistsize) { 1131 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1132 if (kev->filter == kn->kn_filter) 1133 break; 1134 } 1135 } else { 1136 if ((kev->flags & EV_ADD) == EV_ADD) 1137 kqueue_expand(kq, fops, kev->ident, waitok); 1138 1139 KQ_LOCK(kq); 1140 if (kq->kq_knhashmask != 0) { 1141 struct klist *list; 1142 1143 list = &kq->kq_knhash[ 1144 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1145 SLIST_FOREACH(kn, list, kn_link) 1146 if (kev->ident == kn->kn_id && 1147 kev->filter == kn->kn_filter) 1148 break; 1149 } 1150 } 1151 1152 /* knote is in the process of changing, wait for it to stablize. */ 1153 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1154 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1155 if (filedesc_unlock) { 1156 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1157 filedesc_unlock = 0; 1158 } 1159 kq->kq_state |= KQ_FLUXWAIT; 1160 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1161 if (fp != NULL) { 1162 fdrop(fp, td); 1163 fp = NULL; 1164 } 1165 goto findkn; 1166 } 1167 1168 /* 1169 * kn now contains the matching knote, or NULL if no match 1170 */ 1171 if (kn == NULL) { 1172 if (kev->flags & EV_ADD) { 1173 kn = tkn; 1174 tkn = NULL; 1175 if (kn == NULL) { 1176 KQ_UNLOCK(kq); 1177 error = ENOMEM; 1178 goto done; 1179 } 1180 kn->kn_fp = fp; 1181 kn->kn_kq = kq; 1182 kn->kn_fop = fops; 1183 /* 1184 * apply reference counts to knote structure, and 1185 * do not release it at the end of this routine. 1186 */ 1187 fops = NULL; 1188 fp = NULL; 1189 1190 kn->kn_sfflags = kev->fflags; 1191 kn->kn_sdata = kev->data; 1192 kev->fflags = 0; 1193 kev->data = 0; 1194 kn->kn_kevent = *kev; 1195 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1196 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1197 kn->kn_status = KN_INFLUX|KN_DETACHED; 1198 1199 error = knote_attach(kn, kq); 1200 KQ_UNLOCK(kq); 1201 if (error != 0) { 1202 tkn = kn; 1203 goto done; 1204 } 1205 1206 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1207 knote_drop(kn, td); 1208 goto done; 1209 } 1210 KN_LIST_LOCK(kn); 1211 goto done_ev_add; 1212 } else { 1213 /* No matching knote and the EV_ADD flag is not set. */ 1214 KQ_UNLOCK(kq); 1215 error = ENOENT; 1216 goto done; 1217 } 1218 } 1219 1220 if (kev->flags & EV_DELETE) { 1221 kn->kn_status |= KN_INFLUX; 1222 KQ_UNLOCK(kq); 1223 if (!(kn->kn_status & KN_DETACHED)) 1224 kn->kn_fop->f_detach(kn); 1225 knote_drop(kn, td); 1226 goto done; 1227 } 1228 1229 if (kev->flags & EV_FORCEONESHOT) { 1230 kn->kn_flags |= EV_ONESHOT; 1231 KNOTE_ACTIVATE(kn, 1); 1232 } 1233 1234 /* 1235 * The user may change some filter values after the initial EV_ADD, 1236 * but doing so will not reset any filter which has already been 1237 * triggered. 1238 */ 1239 kn->kn_status |= KN_INFLUX | KN_SCAN; 1240 KQ_UNLOCK(kq); 1241 KN_LIST_LOCK(kn); 1242 kn->kn_kevent.udata = kev->udata; 1243 if (!fops->f_isfd && fops->f_touch != NULL) { 1244 fops->f_touch(kn, kev, EVENT_REGISTER); 1245 } else { 1246 kn->kn_sfflags = kev->fflags; 1247 kn->kn_sdata = kev->data; 1248 } 1249 1250 /* 1251 * We can get here with kn->kn_knlist == NULL. This can happen when 1252 * the initial attach event decides that the event is "completed" 1253 * already. i.e. filt_procattach is called on a zombie process. It 1254 * will call filt_proc which will remove it from the list, and NULL 1255 * kn_knlist. 1256 */ 1257 done_ev_add: 1258 if ((kev->flags & EV_DISABLE) && 1259 ((kn->kn_status & KN_DISABLED) == 0)) { 1260 kn->kn_status |= KN_DISABLED; 1261 } 1262 1263 if ((kn->kn_status & KN_DISABLED) == 0) 1264 event = kn->kn_fop->f_event(kn, 0); 1265 else 1266 event = 0; 1267 KQ_LOCK(kq); 1268 if (event) 1269 KNOTE_ACTIVATE(kn, 1); 1270 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1271 KN_LIST_UNLOCK(kn); 1272 1273 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1274 kn->kn_status &= ~KN_DISABLED; 1275 if ((kn->kn_status & KN_ACTIVE) && 1276 ((kn->kn_status & KN_QUEUED) == 0)) 1277 knote_enqueue(kn); 1278 } 1279 KQ_UNLOCK_FLUX(kq); 1280 1281 done: 1282 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1283 if (filedesc_unlock) 1284 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1285 if (fp != NULL) 1286 fdrop(fp, td); 1287 if (tkn != NULL) 1288 knote_free(tkn); 1289 if (fops != NULL) 1290 kqueue_fo_release(filt); 1291 return (error); 1292 } 1293 1294 static int 1295 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1296 { 1297 int error; 1298 struct kqueue *kq; 1299 1300 error = 0; 1301 1302 kq = fp->f_data; 1303 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1304 return (EBADF); 1305 *kqp = kq; 1306 KQ_LOCK(kq); 1307 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1308 KQ_UNLOCK(kq); 1309 return (EBADF); 1310 } 1311 kq->kq_refcnt++; 1312 KQ_UNLOCK(kq); 1313 1314 return error; 1315 } 1316 1317 static void 1318 kqueue_release(struct kqueue *kq, int locked) 1319 { 1320 if (locked) 1321 KQ_OWNED(kq); 1322 else 1323 KQ_LOCK(kq); 1324 kq->kq_refcnt--; 1325 if (kq->kq_refcnt == 1) 1326 wakeup(&kq->kq_refcnt); 1327 if (!locked) 1328 KQ_UNLOCK(kq); 1329 } 1330 1331 static void 1332 kqueue_schedtask(struct kqueue *kq) 1333 { 1334 1335 KQ_OWNED(kq); 1336 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1337 ("scheduling kqueue task while draining")); 1338 1339 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1340 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1341 kq->kq_state |= KQ_TASKSCHED; 1342 } 1343 } 1344 1345 /* 1346 * Expand the kq to make sure we have storage for fops/ident pair. 1347 * 1348 * Return 0 on success (or no work necessary), return errno on failure. 1349 * 1350 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1351 * If kqueue_register is called from a non-fd context, there usually/should 1352 * be no locks held. 1353 */ 1354 static int 1355 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1356 int waitok) 1357 { 1358 struct klist *list, *tmp_knhash, *to_free; 1359 u_long tmp_knhashmask; 1360 int size; 1361 int fd; 1362 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1363 1364 KQ_NOTOWNED(kq); 1365 1366 to_free = NULL; 1367 if (fops->f_isfd) { 1368 fd = ident; 1369 if (kq->kq_knlistsize <= fd) { 1370 size = kq->kq_knlistsize; 1371 while (size <= fd) 1372 size += KQEXTENT; 1373 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1374 if (list == NULL) 1375 return ENOMEM; 1376 KQ_LOCK(kq); 1377 if (kq->kq_knlistsize > fd) { 1378 to_free = list; 1379 list = NULL; 1380 } else { 1381 if (kq->kq_knlist != NULL) { 1382 bcopy(kq->kq_knlist, list, 1383 kq->kq_knlistsize * sizeof(*list)); 1384 to_free = kq->kq_knlist; 1385 kq->kq_knlist = NULL; 1386 } 1387 bzero((caddr_t)list + 1388 kq->kq_knlistsize * sizeof(*list), 1389 (size - kq->kq_knlistsize) * sizeof(*list)); 1390 kq->kq_knlistsize = size; 1391 kq->kq_knlist = list; 1392 } 1393 KQ_UNLOCK(kq); 1394 } 1395 } else { 1396 if (kq->kq_knhashmask == 0) { 1397 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1398 &tmp_knhashmask); 1399 if (tmp_knhash == NULL) 1400 return ENOMEM; 1401 KQ_LOCK(kq); 1402 if (kq->kq_knhashmask == 0) { 1403 kq->kq_knhash = tmp_knhash; 1404 kq->kq_knhashmask = tmp_knhashmask; 1405 } else { 1406 to_free = tmp_knhash; 1407 } 1408 KQ_UNLOCK(kq); 1409 } 1410 } 1411 free(to_free, M_KQUEUE); 1412 1413 KQ_NOTOWNED(kq); 1414 return 0; 1415 } 1416 1417 static void 1418 kqueue_task(void *arg, int pending) 1419 { 1420 struct kqueue *kq; 1421 int haskqglobal; 1422 1423 haskqglobal = 0; 1424 kq = arg; 1425 1426 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1427 KQ_LOCK(kq); 1428 1429 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1430 1431 kq->kq_state &= ~KQ_TASKSCHED; 1432 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1433 wakeup(&kq->kq_state); 1434 } 1435 KQ_UNLOCK(kq); 1436 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1437 } 1438 1439 /* 1440 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1441 * We treat KN_MARKER knotes as if they are INFLUX. 1442 */ 1443 static int 1444 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1445 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1446 { 1447 struct kevent *kevp; 1448 struct knote *kn, *marker; 1449 sbintime_t asbt, rsbt; 1450 int count, error, haskqglobal, influx, nkev, touch; 1451 1452 count = maxevents; 1453 nkev = 0; 1454 error = 0; 1455 haskqglobal = 0; 1456 1457 if (maxevents == 0) 1458 goto done_nl; 1459 1460 rsbt = 0; 1461 if (tsp != NULL) { 1462 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1463 tsp->tv_nsec >= 1000000000) { 1464 error = EINVAL; 1465 goto done_nl; 1466 } 1467 if (timespecisset(tsp)) { 1468 if (tsp->tv_sec <= INT32_MAX) { 1469 rsbt = tstosbt(*tsp); 1470 if (TIMESEL(&asbt, rsbt)) 1471 asbt += tc_tick_sbt; 1472 if (asbt <= SBT_MAX - rsbt) 1473 asbt += rsbt; 1474 else 1475 asbt = 0; 1476 rsbt >>= tc_precexp; 1477 } else 1478 asbt = 0; 1479 } else 1480 asbt = -1; 1481 } else 1482 asbt = 0; 1483 marker = knote_alloc(1); 1484 if (marker == NULL) { 1485 error = ENOMEM; 1486 goto done_nl; 1487 } 1488 marker->kn_status = KN_MARKER; 1489 KQ_LOCK(kq); 1490 1491 retry: 1492 kevp = keva; 1493 if (kq->kq_count == 0) { 1494 if (asbt == -1) { 1495 error = EWOULDBLOCK; 1496 } else { 1497 kq->kq_state |= KQ_SLEEP; 1498 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1499 "kqread", asbt, rsbt, C_ABSOLUTE); 1500 } 1501 if (error == 0) 1502 goto retry; 1503 /* don't restart after signals... */ 1504 if (error == ERESTART) 1505 error = EINTR; 1506 else if (error == EWOULDBLOCK) 1507 error = 0; 1508 goto done; 1509 } 1510 1511 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1512 influx = 0; 1513 while (count) { 1514 KQ_OWNED(kq); 1515 kn = TAILQ_FIRST(&kq->kq_head); 1516 1517 if ((kn->kn_status == KN_MARKER && kn != marker) || 1518 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1519 if (influx) { 1520 influx = 0; 1521 KQ_FLUX_WAKEUP(kq); 1522 } 1523 kq->kq_state |= KQ_FLUXWAIT; 1524 error = msleep(kq, &kq->kq_lock, PSOCK, 1525 "kqflxwt", 0); 1526 continue; 1527 } 1528 1529 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1530 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1531 kn->kn_status &= ~KN_QUEUED; 1532 kq->kq_count--; 1533 continue; 1534 } 1535 if (kn == marker) { 1536 KQ_FLUX_WAKEUP(kq); 1537 if (count == maxevents) 1538 goto retry; 1539 goto done; 1540 } 1541 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1542 ("KN_INFLUX set when not suppose to be")); 1543 1544 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1545 kn->kn_status &= ~KN_QUEUED; 1546 kn->kn_status |= KN_INFLUX; 1547 kq->kq_count--; 1548 KQ_UNLOCK(kq); 1549 /* 1550 * We don't need to lock the list since we've marked 1551 * it _INFLUX. 1552 */ 1553 if (!(kn->kn_status & KN_DETACHED)) 1554 kn->kn_fop->f_detach(kn); 1555 knote_drop(kn, td); 1556 KQ_LOCK(kq); 1557 continue; 1558 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1559 kn->kn_status &= ~KN_QUEUED; 1560 kn->kn_status |= KN_INFLUX; 1561 kq->kq_count--; 1562 KQ_UNLOCK(kq); 1563 /* 1564 * We don't need to lock the list since we've marked 1565 * it _INFLUX. 1566 */ 1567 *kevp = kn->kn_kevent; 1568 if (!(kn->kn_status & KN_DETACHED)) 1569 kn->kn_fop->f_detach(kn); 1570 knote_drop(kn, td); 1571 KQ_LOCK(kq); 1572 kn = NULL; 1573 } else { 1574 kn->kn_status |= KN_INFLUX | KN_SCAN; 1575 KQ_UNLOCK(kq); 1576 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1577 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1578 KN_LIST_LOCK(kn); 1579 if (kn->kn_fop->f_event(kn, 0) == 0) { 1580 KQ_LOCK(kq); 1581 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1582 kn->kn_status &= 1583 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1584 KN_SCAN); 1585 kq->kq_count--; 1586 KN_LIST_UNLOCK(kn); 1587 influx = 1; 1588 continue; 1589 } 1590 touch = (!kn->kn_fop->f_isfd && 1591 kn->kn_fop->f_touch != NULL); 1592 if (touch) 1593 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1594 else 1595 *kevp = kn->kn_kevent; 1596 KQ_LOCK(kq); 1597 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1598 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1599 /* 1600 * Manually clear knotes who weren't 1601 * 'touch'ed. 1602 */ 1603 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1604 kn->kn_data = 0; 1605 kn->kn_fflags = 0; 1606 } 1607 if (kn->kn_flags & EV_DISPATCH) 1608 kn->kn_status |= KN_DISABLED; 1609 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1610 kq->kq_count--; 1611 } else 1612 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1613 1614 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1615 KN_LIST_UNLOCK(kn); 1616 influx = 1; 1617 } 1618 1619 /* we are returning a copy to the user */ 1620 kevp++; 1621 nkev++; 1622 count--; 1623 1624 if (nkev == KQ_NEVENTS) { 1625 influx = 0; 1626 KQ_UNLOCK_FLUX(kq); 1627 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1628 nkev = 0; 1629 kevp = keva; 1630 KQ_LOCK(kq); 1631 if (error) 1632 break; 1633 } 1634 } 1635 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1636 done: 1637 KQ_OWNED(kq); 1638 KQ_UNLOCK_FLUX(kq); 1639 knote_free(marker); 1640 done_nl: 1641 KQ_NOTOWNED(kq); 1642 if (nkev != 0) 1643 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1644 td->td_retval[0] = maxevents - count; 1645 return (error); 1646 } 1647 1648 /*ARGSUSED*/ 1649 static int 1650 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1651 struct ucred *active_cred, struct thread *td) 1652 { 1653 /* 1654 * Enabling sigio causes two major problems: 1655 * 1) infinite recursion: 1656 * Synopsys: kevent is being used to track signals and have FIOASYNC 1657 * set. On receipt of a signal this will cause a kqueue to recurse 1658 * into itself over and over. Sending the sigio causes the kqueue 1659 * to become ready, which in turn posts sigio again, forever. 1660 * Solution: this can be solved by setting a flag in the kqueue that 1661 * we have a SIGIO in progress. 1662 * 2) locking problems: 1663 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1664 * us above the proc and pgrp locks. 1665 * Solution: Post a signal using an async mechanism, being sure to 1666 * record a generation count in the delivery so that we do not deliver 1667 * a signal to the wrong process. 1668 * 1669 * Note, these two mechanisms are somewhat mutually exclusive! 1670 */ 1671 #if 0 1672 struct kqueue *kq; 1673 1674 kq = fp->f_data; 1675 switch (cmd) { 1676 case FIOASYNC: 1677 if (*(int *)data) { 1678 kq->kq_state |= KQ_ASYNC; 1679 } else { 1680 kq->kq_state &= ~KQ_ASYNC; 1681 } 1682 return (0); 1683 1684 case FIOSETOWN: 1685 return (fsetown(*(int *)data, &kq->kq_sigio)); 1686 1687 case FIOGETOWN: 1688 *(int *)data = fgetown(&kq->kq_sigio); 1689 return (0); 1690 } 1691 #endif 1692 1693 return (ENOTTY); 1694 } 1695 1696 /*ARGSUSED*/ 1697 static int 1698 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1699 struct thread *td) 1700 { 1701 struct kqueue *kq; 1702 int revents = 0; 1703 int error; 1704 1705 if ((error = kqueue_acquire(fp, &kq))) 1706 return POLLERR; 1707 1708 KQ_LOCK(kq); 1709 if (events & (POLLIN | POLLRDNORM)) { 1710 if (kq->kq_count) { 1711 revents |= events & (POLLIN | POLLRDNORM); 1712 } else { 1713 selrecord(td, &kq->kq_sel); 1714 if (SEL_WAITING(&kq->kq_sel)) 1715 kq->kq_state |= KQ_SEL; 1716 } 1717 } 1718 kqueue_release(kq, 1); 1719 KQ_UNLOCK(kq); 1720 return (revents); 1721 } 1722 1723 /*ARGSUSED*/ 1724 static int 1725 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1726 struct thread *td) 1727 { 1728 1729 bzero((void *)st, sizeof *st); 1730 /* 1731 * We no longer return kq_count because the unlocked value is useless. 1732 * If you spent all this time getting the count, why not spend your 1733 * syscall better by calling kevent? 1734 * 1735 * XXX - This is needed for libc_r. 1736 */ 1737 st->st_mode = S_IFIFO; 1738 return (0); 1739 } 1740 1741 /*ARGSUSED*/ 1742 static int 1743 kqueue_close(struct file *fp, struct thread *td) 1744 { 1745 struct kqueue *kq = fp->f_data; 1746 struct filedesc *fdp; 1747 struct knote *kn; 1748 int i; 1749 int error; 1750 int filedesc_unlock; 1751 1752 if ((error = kqueue_acquire(fp, &kq))) 1753 return error; 1754 1755 filedesc_unlock = 0; 1756 KQ_LOCK(kq); 1757 1758 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1759 ("kqueue already closing")); 1760 kq->kq_state |= KQ_CLOSING; 1761 if (kq->kq_refcnt > 1) 1762 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1763 1764 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1765 fdp = kq->kq_fdp; 1766 1767 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1768 ("kqueue's knlist not empty")); 1769 1770 for (i = 0; i < kq->kq_knlistsize; i++) { 1771 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1772 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1773 kq->kq_state |= KQ_FLUXWAIT; 1774 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 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 if (kq->kq_knhashmask != 0) { 1786 for (i = 0; i <= kq->kq_knhashmask; i++) { 1787 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1788 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1789 kq->kq_state |= KQ_FLUXWAIT; 1790 msleep(kq, &kq->kq_lock, PSOCK, 1791 "kqclo2", 0); 1792 continue; 1793 } 1794 kn->kn_status |= KN_INFLUX; 1795 KQ_UNLOCK(kq); 1796 if (!(kn->kn_status & KN_DETACHED)) 1797 kn->kn_fop->f_detach(kn); 1798 knote_drop(kn, td); 1799 KQ_LOCK(kq); 1800 } 1801 } 1802 } 1803 1804 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1805 kq->kq_state |= KQ_TASKDRAIN; 1806 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1807 } 1808 1809 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1810 selwakeuppri(&kq->kq_sel, PSOCK); 1811 if (!SEL_WAITING(&kq->kq_sel)) 1812 kq->kq_state &= ~KQ_SEL; 1813 } 1814 1815 KQ_UNLOCK(kq); 1816 1817 /* 1818 * We could be called due to the knote_drop() doing fdrop(), 1819 * called from kqueue_register(). In this case the global 1820 * lock is owned, and filedesc sx is locked before, to not 1821 * take the sleepable lock after non-sleepable. 1822 */ 1823 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1824 FILEDESC_XLOCK(fdp); 1825 filedesc_unlock = 1; 1826 } else 1827 filedesc_unlock = 0; 1828 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1829 if (filedesc_unlock) 1830 FILEDESC_XUNLOCK(fdp); 1831 1832 seldrain(&kq->kq_sel); 1833 knlist_destroy(&kq->kq_sel.si_note); 1834 mtx_destroy(&kq->kq_lock); 1835 kq->kq_fdp = NULL; 1836 1837 if (kq->kq_knhash != NULL) 1838 free(kq->kq_knhash, M_KQUEUE); 1839 if (kq->kq_knlist != NULL) 1840 free(kq->kq_knlist, M_KQUEUE); 1841 1842 funsetown(&kq->kq_sigio); 1843 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1844 crfree(kq->kq_cred); 1845 free(kq, M_KQUEUE); 1846 fp->f_data = NULL; 1847 1848 return (0); 1849 } 1850 1851 static int 1852 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 1853 { 1854 1855 kif->kf_type = KF_TYPE_KQUEUE; 1856 return (0); 1857 } 1858 1859 static void 1860 kqueue_wakeup(struct kqueue *kq) 1861 { 1862 KQ_OWNED(kq); 1863 1864 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1865 kq->kq_state &= ~KQ_SLEEP; 1866 wakeup(kq); 1867 } 1868 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1869 selwakeuppri(&kq->kq_sel, PSOCK); 1870 if (!SEL_WAITING(&kq->kq_sel)) 1871 kq->kq_state &= ~KQ_SEL; 1872 } 1873 if (!knlist_empty(&kq->kq_sel.si_note)) 1874 kqueue_schedtask(kq); 1875 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1876 pgsigio(&kq->kq_sigio, SIGIO, 0); 1877 } 1878 } 1879 1880 /* 1881 * Walk down a list of knotes, activating them if their event has triggered. 1882 * 1883 * There is a possibility to optimize in the case of one kq watching another. 1884 * Instead of scheduling a task to wake it up, you could pass enough state 1885 * down the chain to make up the parent kqueue. Make this code functional 1886 * first. 1887 */ 1888 void 1889 knote(struct knlist *list, long hint, int lockflags) 1890 { 1891 struct kqueue *kq; 1892 struct knote *kn; 1893 int error; 1894 1895 if (list == NULL) 1896 return; 1897 1898 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1899 1900 if ((lockflags & KNF_LISTLOCKED) == 0) 1901 list->kl_lock(list->kl_lockarg); 1902 1903 /* 1904 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1905 * the kqueue scheduling, but this will introduce four 1906 * lock/unlock's for each knote to test. If we do, continue to use 1907 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1908 * only safe if you want to remove the current item, which we are 1909 * not doing. 1910 */ 1911 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1912 kq = kn->kn_kq; 1913 KQ_LOCK(kq); 1914 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1915 /* 1916 * Do not process the influx notes, except for 1917 * the influx coming from the kq unlock in the 1918 * kqueue_scan(). In the later case, we do 1919 * not interfere with the scan, since the code 1920 * fragment in kqueue_scan() locks the knlist, 1921 * and cannot proceed until we finished. 1922 */ 1923 KQ_UNLOCK(kq); 1924 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1925 kn->kn_status |= KN_INFLUX; 1926 KQ_UNLOCK(kq); 1927 error = kn->kn_fop->f_event(kn, hint); 1928 KQ_LOCK(kq); 1929 kn->kn_status &= ~KN_INFLUX; 1930 if (error) 1931 KNOTE_ACTIVATE(kn, 1); 1932 KQ_UNLOCK_FLUX(kq); 1933 } else { 1934 kn->kn_status |= KN_HASKQLOCK; 1935 if (kn->kn_fop->f_event(kn, hint)) 1936 KNOTE_ACTIVATE(kn, 1); 1937 kn->kn_status &= ~KN_HASKQLOCK; 1938 KQ_UNLOCK(kq); 1939 } 1940 } 1941 if ((lockflags & KNF_LISTLOCKED) == 0) 1942 list->kl_unlock(list->kl_lockarg); 1943 } 1944 1945 /* 1946 * add a knote to a knlist 1947 */ 1948 void 1949 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1950 { 1951 KNL_ASSERT_LOCK(knl, islocked); 1952 KQ_NOTOWNED(kn->kn_kq); 1953 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1954 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1955 if (!islocked) 1956 knl->kl_lock(knl->kl_lockarg); 1957 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1958 if (!islocked) 1959 knl->kl_unlock(knl->kl_lockarg); 1960 KQ_LOCK(kn->kn_kq); 1961 kn->kn_knlist = knl; 1962 kn->kn_status &= ~KN_DETACHED; 1963 KQ_UNLOCK(kn->kn_kq); 1964 } 1965 1966 static void 1967 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1968 { 1969 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1970 KNL_ASSERT_LOCK(knl, knlislocked); 1971 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1972 if (!kqislocked) 1973 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1974 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1975 if (!knlislocked) 1976 knl->kl_lock(knl->kl_lockarg); 1977 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1978 kn->kn_knlist = NULL; 1979 if (!knlislocked) 1980 knl->kl_unlock(knl->kl_lockarg); 1981 if (!kqislocked) 1982 KQ_LOCK(kn->kn_kq); 1983 kn->kn_status |= KN_DETACHED; 1984 if (!kqislocked) 1985 KQ_UNLOCK(kn->kn_kq); 1986 } 1987 1988 /* 1989 * remove knote from the specified knlist 1990 */ 1991 void 1992 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1993 { 1994 1995 knlist_remove_kq(knl, kn, islocked, 0); 1996 } 1997 1998 /* 1999 * remove knote from the specified knlist while in f_event handler. 2000 */ 2001 void 2002 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 2003 { 2004 2005 knlist_remove_kq(knl, kn, 1, 2006 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 2007 } 2008 2009 int 2010 knlist_empty(struct knlist *knl) 2011 { 2012 2013 KNL_ASSERT_LOCKED(knl); 2014 return SLIST_EMPTY(&knl->kl_list); 2015 } 2016 2017 static struct mtx knlist_lock; 2018 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2019 MTX_DEF); 2020 static void knlist_mtx_lock(void *arg); 2021 static void knlist_mtx_unlock(void *arg); 2022 2023 static void 2024 knlist_mtx_lock(void *arg) 2025 { 2026 2027 mtx_lock((struct mtx *)arg); 2028 } 2029 2030 static void 2031 knlist_mtx_unlock(void *arg) 2032 { 2033 2034 mtx_unlock((struct mtx *)arg); 2035 } 2036 2037 static void 2038 knlist_mtx_assert_locked(void *arg) 2039 { 2040 2041 mtx_assert((struct mtx *)arg, MA_OWNED); 2042 } 2043 2044 static void 2045 knlist_mtx_assert_unlocked(void *arg) 2046 { 2047 2048 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2049 } 2050 2051 static void 2052 knlist_rw_rlock(void *arg) 2053 { 2054 2055 rw_rlock((struct rwlock *)arg); 2056 } 2057 2058 static void 2059 knlist_rw_runlock(void *arg) 2060 { 2061 2062 rw_runlock((struct rwlock *)arg); 2063 } 2064 2065 static void 2066 knlist_rw_assert_locked(void *arg) 2067 { 2068 2069 rw_assert((struct rwlock *)arg, RA_LOCKED); 2070 } 2071 2072 static void 2073 knlist_rw_assert_unlocked(void *arg) 2074 { 2075 2076 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2077 } 2078 2079 void 2080 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2081 void (*kl_unlock)(void *), 2082 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2083 { 2084 2085 if (lock == NULL) 2086 knl->kl_lockarg = &knlist_lock; 2087 else 2088 knl->kl_lockarg = lock; 2089 2090 if (kl_lock == NULL) 2091 knl->kl_lock = knlist_mtx_lock; 2092 else 2093 knl->kl_lock = kl_lock; 2094 if (kl_unlock == NULL) 2095 knl->kl_unlock = knlist_mtx_unlock; 2096 else 2097 knl->kl_unlock = kl_unlock; 2098 if (kl_assert_locked == NULL) 2099 knl->kl_assert_locked = knlist_mtx_assert_locked; 2100 else 2101 knl->kl_assert_locked = kl_assert_locked; 2102 if (kl_assert_unlocked == NULL) 2103 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2104 else 2105 knl->kl_assert_unlocked = kl_assert_unlocked; 2106 2107 SLIST_INIT(&knl->kl_list); 2108 } 2109 2110 void 2111 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2112 { 2113 2114 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2115 } 2116 2117 void 2118 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2119 { 2120 2121 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2122 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2123 } 2124 2125 void 2126 knlist_destroy(struct knlist *knl) 2127 { 2128 2129 #ifdef INVARIANTS 2130 /* 2131 * if we run across this error, we need to find the offending 2132 * driver and have it call knlist_clear or knlist_delete. 2133 */ 2134 if (!SLIST_EMPTY(&knl->kl_list)) 2135 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2136 #endif 2137 2138 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2139 SLIST_INIT(&knl->kl_list); 2140 } 2141 2142 /* 2143 * Even if we are locked, we may need to drop the lock to allow any influx 2144 * knotes time to "settle". 2145 */ 2146 void 2147 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2148 { 2149 struct knote *kn, *kn2; 2150 struct kqueue *kq; 2151 2152 if (islocked) 2153 KNL_ASSERT_LOCKED(knl); 2154 else { 2155 KNL_ASSERT_UNLOCKED(knl); 2156 again: /* need to reacquire lock since we have dropped it */ 2157 knl->kl_lock(knl->kl_lockarg); 2158 } 2159 2160 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2161 kq = kn->kn_kq; 2162 KQ_LOCK(kq); 2163 if ((kn->kn_status & KN_INFLUX)) { 2164 KQ_UNLOCK(kq); 2165 continue; 2166 } 2167 knlist_remove_kq(knl, kn, 1, 1); 2168 if (killkn) { 2169 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2170 KQ_UNLOCK(kq); 2171 knote_drop(kn, td); 2172 } else { 2173 /* Make sure cleared knotes disappear soon */ 2174 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2175 KQ_UNLOCK(kq); 2176 } 2177 kq = NULL; 2178 } 2179 2180 if (!SLIST_EMPTY(&knl->kl_list)) { 2181 /* there are still KN_INFLUX remaining */ 2182 kn = SLIST_FIRST(&knl->kl_list); 2183 kq = kn->kn_kq; 2184 KQ_LOCK(kq); 2185 KASSERT(kn->kn_status & KN_INFLUX, 2186 ("knote removed w/o list lock")); 2187 knl->kl_unlock(knl->kl_lockarg); 2188 kq->kq_state |= KQ_FLUXWAIT; 2189 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2190 kq = NULL; 2191 goto again; 2192 } 2193 2194 if (islocked) 2195 KNL_ASSERT_LOCKED(knl); 2196 else { 2197 knl->kl_unlock(knl->kl_lockarg); 2198 KNL_ASSERT_UNLOCKED(knl); 2199 } 2200 } 2201 2202 /* 2203 * Remove all knotes referencing a specified fd must be called with FILEDESC 2204 * lock. This prevents a race where a new fd comes along and occupies the 2205 * entry and we attach a knote to the fd. 2206 */ 2207 void 2208 knote_fdclose(struct thread *td, int fd) 2209 { 2210 struct filedesc *fdp = td->td_proc->p_fd; 2211 struct kqueue *kq; 2212 struct knote *kn; 2213 int influx; 2214 2215 FILEDESC_XLOCK_ASSERT(fdp); 2216 2217 /* 2218 * We shouldn't have to worry about new kevents appearing on fd 2219 * since filedesc is locked. 2220 */ 2221 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2222 KQ_LOCK(kq); 2223 2224 again: 2225 influx = 0; 2226 while (kq->kq_knlistsize > fd && 2227 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2228 if (kn->kn_status & KN_INFLUX) { 2229 /* someone else might be waiting on our knote */ 2230 if (influx) 2231 wakeup(kq); 2232 kq->kq_state |= KQ_FLUXWAIT; 2233 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2234 goto again; 2235 } 2236 kn->kn_status |= KN_INFLUX; 2237 KQ_UNLOCK(kq); 2238 if (!(kn->kn_status & KN_DETACHED)) 2239 kn->kn_fop->f_detach(kn); 2240 knote_drop(kn, td); 2241 influx = 1; 2242 KQ_LOCK(kq); 2243 } 2244 KQ_UNLOCK_FLUX(kq); 2245 } 2246 } 2247 2248 static int 2249 knote_attach(struct knote *kn, struct kqueue *kq) 2250 { 2251 struct klist *list; 2252 2253 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2254 KQ_OWNED(kq); 2255 2256 if (kn->kn_fop->f_isfd) { 2257 if (kn->kn_id >= kq->kq_knlistsize) 2258 return ENOMEM; 2259 list = &kq->kq_knlist[kn->kn_id]; 2260 } else { 2261 if (kq->kq_knhash == NULL) 2262 return ENOMEM; 2263 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2264 } 2265 2266 SLIST_INSERT_HEAD(list, kn, kn_link); 2267 2268 return 0; 2269 } 2270 2271 /* 2272 * knote must already have been detached using the f_detach method. 2273 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2274 * to prevent other removal. 2275 */ 2276 static void 2277 knote_drop(struct knote *kn, struct thread *td) 2278 { 2279 struct kqueue *kq; 2280 struct klist *list; 2281 2282 kq = kn->kn_kq; 2283 2284 KQ_NOTOWNED(kq); 2285 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2286 ("knote_drop called without KN_INFLUX set in kn_status")); 2287 2288 KQ_LOCK(kq); 2289 if (kn->kn_fop->f_isfd) 2290 list = &kq->kq_knlist[kn->kn_id]; 2291 else 2292 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2293 2294 if (!SLIST_EMPTY(list)) 2295 SLIST_REMOVE(list, kn, knote, kn_link); 2296 if (kn->kn_status & KN_QUEUED) 2297 knote_dequeue(kn); 2298 KQ_UNLOCK_FLUX(kq); 2299 2300 if (kn->kn_fop->f_isfd) { 2301 fdrop(kn->kn_fp, td); 2302 kn->kn_fp = NULL; 2303 } 2304 kqueue_fo_release(kn->kn_kevent.filter); 2305 kn->kn_fop = NULL; 2306 knote_free(kn); 2307 } 2308 2309 static void 2310 knote_enqueue(struct knote *kn) 2311 { 2312 struct kqueue *kq = kn->kn_kq; 2313 2314 KQ_OWNED(kn->kn_kq); 2315 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2316 2317 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2318 kn->kn_status |= KN_QUEUED; 2319 kq->kq_count++; 2320 kqueue_wakeup(kq); 2321 } 2322 2323 static void 2324 knote_dequeue(struct knote *kn) 2325 { 2326 struct kqueue *kq = kn->kn_kq; 2327 2328 KQ_OWNED(kn->kn_kq); 2329 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2330 2331 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2332 kn->kn_status &= ~KN_QUEUED; 2333 kq->kq_count--; 2334 } 2335 2336 static void 2337 knote_init(void) 2338 { 2339 2340 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2341 NULL, NULL, UMA_ALIGN_PTR, 0); 2342 } 2343 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2344 2345 static struct knote * 2346 knote_alloc(int waitok) 2347 { 2348 return ((struct knote *)uma_zalloc(knote_zone, 2349 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2350 } 2351 2352 static void 2353 knote_free(struct knote *kn) 2354 { 2355 if (kn != NULL) 2356 uma_zfree(knote_zone, kn); 2357 } 2358 2359 /* 2360 * Register the kev w/ the kq specified by fd. 2361 */ 2362 int 2363 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2364 { 2365 struct kqueue *kq; 2366 struct file *fp; 2367 cap_rights_t rights; 2368 int error; 2369 2370 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2371 if (error != 0) 2372 return (error); 2373 if ((error = kqueue_acquire(fp, &kq)) != 0) 2374 goto noacquire; 2375 2376 error = kqueue_register(kq, kev, td, waitok); 2377 2378 kqueue_release(kq, 0); 2379 2380 noacquire: 2381 fdrop(fp, td); 2382 2383 return error; 2384 } 2385