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 void kqueue_destroy(struct kqueue *kq); 103 static void kqueue_drain(struct kqueue *kq, struct thread *td); 104 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 105 uintptr_t ident, int waitok); 106 static void kqueue_task(void *arg, int pending); 107 static int kqueue_scan(struct kqueue *kq, int maxevents, 108 struct kevent_copyops *k_ops, 109 const struct timespec *timeout, 110 struct kevent *keva, struct thread *td); 111 static void kqueue_wakeup(struct kqueue *kq); 112 static struct filterops *kqueue_fo_find(int filt); 113 static void kqueue_fo_release(int filt); 114 115 static fo_ioctl_t kqueue_ioctl; 116 static fo_poll_t kqueue_poll; 117 static fo_kqfilter_t kqueue_kqfilter; 118 static fo_stat_t kqueue_stat; 119 static fo_close_t kqueue_close; 120 static fo_fill_kinfo_t kqueue_fill_kinfo; 121 122 static struct fileops kqueueops = { 123 .fo_read = invfo_rdwr, 124 .fo_write = invfo_rdwr, 125 .fo_truncate = invfo_truncate, 126 .fo_ioctl = kqueue_ioctl, 127 .fo_poll = kqueue_poll, 128 .fo_kqfilter = kqueue_kqfilter, 129 .fo_stat = kqueue_stat, 130 .fo_close = kqueue_close, 131 .fo_chmod = invfo_chmod, 132 .fo_chown = invfo_chown, 133 .fo_sendfile = invfo_sendfile, 134 .fo_fill_kinfo = kqueue_fill_kinfo, 135 }; 136 137 static int knote_attach(struct knote *kn, struct kqueue *kq); 138 static void knote_drop(struct knote *kn, struct thread *td); 139 static void knote_enqueue(struct knote *kn); 140 static void knote_dequeue(struct knote *kn); 141 static void knote_init(void); 142 static struct knote *knote_alloc(int waitok); 143 static void knote_free(struct knote *kn); 144 145 static void filt_kqdetach(struct knote *kn); 146 static int filt_kqueue(struct knote *kn, long hint); 147 static int filt_procattach(struct knote *kn); 148 static void filt_procdetach(struct knote *kn); 149 static int filt_proc(struct knote *kn, long hint); 150 static int filt_fileattach(struct knote *kn); 151 static void filt_timerexpire(void *knx); 152 static int filt_timerattach(struct knote *kn); 153 static void filt_timerdetach(struct knote *kn); 154 static int filt_timer(struct knote *kn, long hint); 155 static int filt_userattach(struct knote *kn); 156 static void filt_userdetach(struct knote *kn); 157 static int filt_user(struct knote *kn, long hint); 158 static void filt_usertouch(struct knote *kn, struct kevent *kev, 159 u_long type); 160 161 static struct filterops file_filtops = { 162 .f_isfd = 1, 163 .f_attach = filt_fileattach, 164 }; 165 static struct filterops kqread_filtops = { 166 .f_isfd = 1, 167 .f_detach = filt_kqdetach, 168 .f_event = filt_kqueue, 169 }; 170 /* XXX - move to kern_proc.c? */ 171 static struct filterops proc_filtops = { 172 .f_isfd = 0, 173 .f_attach = filt_procattach, 174 .f_detach = filt_procdetach, 175 .f_event = filt_proc, 176 }; 177 static struct filterops timer_filtops = { 178 .f_isfd = 0, 179 .f_attach = filt_timerattach, 180 .f_detach = filt_timerdetach, 181 .f_event = filt_timer, 182 }; 183 static struct filterops user_filtops = { 184 .f_attach = filt_userattach, 185 .f_detach = filt_userdetach, 186 .f_event = filt_user, 187 .f_touch = filt_usertouch, 188 }; 189 190 static uma_zone_t knote_zone; 191 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 192 static unsigned int kq_calloutmax = 4 * 1024; 193 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 194 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 195 196 /* XXX - ensure not KN_INFLUX?? */ 197 #define KNOTE_ACTIVATE(kn, islock) do { \ 198 if ((islock)) \ 199 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 200 else \ 201 KQ_LOCK((kn)->kn_kq); \ 202 (kn)->kn_status |= KN_ACTIVE; \ 203 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 204 knote_enqueue((kn)); \ 205 if (!(islock)) \ 206 KQ_UNLOCK((kn)->kn_kq); \ 207 } while(0) 208 #define KQ_LOCK(kq) do { \ 209 mtx_lock(&(kq)->kq_lock); \ 210 } while (0) 211 #define KQ_FLUX_WAKEUP(kq) do { \ 212 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 213 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 214 wakeup((kq)); \ 215 } \ 216 } while (0) 217 #define KQ_UNLOCK_FLUX(kq) do { \ 218 KQ_FLUX_WAKEUP(kq); \ 219 mtx_unlock(&(kq)->kq_lock); \ 220 } while (0) 221 #define KQ_UNLOCK(kq) do { \ 222 mtx_unlock(&(kq)->kq_lock); \ 223 } while (0) 224 #define KQ_OWNED(kq) do { \ 225 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 226 } while (0) 227 #define KQ_NOTOWNED(kq) do { \ 228 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 229 } while (0) 230 #define KN_LIST_LOCK(kn) do { \ 231 if (kn->kn_knlist != NULL) \ 232 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 233 } while (0) 234 #define KN_LIST_UNLOCK(kn) do { \ 235 if (kn->kn_knlist != NULL) \ 236 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 237 } while (0) 238 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 239 if (islocked) \ 240 KNL_ASSERT_LOCKED(knl); \ 241 else \ 242 KNL_ASSERT_UNLOCKED(knl); \ 243 } while (0) 244 #ifdef INVARIANTS 245 #define KNL_ASSERT_LOCKED(knl) do { \ 246 knl->kl_assert_locked((knl)->kl_lockarg); \ 247 } while (0) 248 #define KNL_ASSERT_UNLOCKED(knl) do { \ 249 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 250 } while (0) 251 #else /* !INVARIANTS */ 252 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 253 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 254 #endif /* INVARIANTS */ 255 256 #ifndef KN_HASHSIZE 257 #define KN_HASHSIZE 64 /* XXX should be tunable */ 258 #endif 259 260 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 261 262 static int 263 filt_nullattach(struct knote *kn) 264 { 265 266 return (ENXIO); 267 }; 268 269 struct filterops null_filtops = { 270 .f_isfd = 0, 271 .f_attach = filt_nullattach, 272 }; 273 274 /* XXX - make SYSINIT to add these, and move into respective modules. */ 275 extern struct filterops sig_filtops; 276 extern struct filterops fs_filtops; 277 278 /* 279 * Table for for all system-defined filters. 280 */ 281 static struct mtx filterops_lock; 282 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 283 MTX_DEF); 284 static struct { 285 struct filterops *for_fop; 286 int for_nolock; 287 int for_refcnt; 288 } sysfilt_ops[EVFILT_SYSCOUNT] = { 289 { &file_filtops, 1 }, /* EVFILT_READ */ 290 { &file_filtops, 1 }, /* EVFILT_WRITE */ 291 { &null_filtops }, /* EVFILT_AIO */ 292 { &file_filtops, 1 }, /* EVFILT_VNODE */ 293 { &proc_filtops, 1 }, /* EVFILT_PROC */ 294 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 295 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 296 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 297 { &fs_filtops, 1 }, /* EVFILT_FS */ 298 { &null_filtops }, /* EVFILT_LIO */ 299 { &user_filtops, 1 }, /* EVFILT_USER */ 300 { &null_filtops }, /* EVFILT_SENDFILE */ 301 }; 302 303 /* 304 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 305 * method. 306 */ 307 static int 308 filt_fileattach(struct knote *kn) 309 { 310 311 return (fo_kqfilter(kn->kn_fp, kn)); 312 } 313 314 /*ARGSUSED*/ 315 static int 316 kqueue_kqfilter(struct file *fp, struct knote *kn) 317 { 318 struct kqueue *kq = kn->kn_fp->f_data; 319 320 if (kn->kn_filter != EVFILT_READ) 321 return (EINVAL); 322 323 kn->kn_status |= KN_KQUEUE; 324 kn->kn_fop = &kqread_filtops; 325 knlist_add(&kq->kq_sel.si_note, kn, 0); 326 327 return (0); 328 } 329 330 static void 331 filt_kqdetach(struct knote *kn) 332 { 333 struct kqueue *kq = kn->kn_fp->f_data; 334 335 knlist_remove(&kq->kq_sel.si_note, kn, 0); 336 } 337 338 /*ARGSUSED*/ 339 static int 340 filt_kqueue(struct knote *kn, long hint) 341 { 342 struct kqueue *kq = kn->kn_fp->f_data; 343 344 kn->kn_data = kq->kq_count; 345 return (kn->kn_data > 0); 346 } 347 348 /* XXX - move to kern_proc.c? */ 349 static int 350 filt_procattach(struct knote *kn) 351 { 352 struct proc *p; 353 int immediate; 354 int error; 355 356 immediate = 0; 357 p = pfind(kn->kn_id); 358 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 359 p = zpfind(kn->kn_id); 360 immediate = 1; 361 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 362 immediate = 1; 363 } 364 365 if (p == NULL) 366 return (ESRCH); 367 if ((error = p_cansee(curthread, p))) { 368 PROC_UNLOCK(p); 369 return (error); 370 } 371 372 kn->kn_ptr.p_proc = p; 373 kn->kn_flags |= EV_CLEAR; /* automatically set */ 374 375 /* 376 * internal flag indicating registration done by kernel 377 */ 378 if (kn->kn_flags & EV_FLAG1) { 379 kn->kn_data = kn->kn_sdata; /* ppid */ 380 kn->kn_fflags = NOTE_CHILD; 381 kn->kn_flags &= ~EV_FLAG1; 382 } 383 384 if (immediate == 0) 385 knlist_add(&p->p_klist, kn, 1); 386 387 /* 388 * Immediately activate any exit notes if the target process is a 389 * zombie. This is necessary to handle the case where the target 390 * process, e.g. a child, dies before the kevent is registered. 391 */ 392 if (immediate && filt_proc(kn, NOTE_EXIT)) 393 KNOTE_ACTIVATE(kn, 0); 394 395 PROC_UNLOCK(p); 396 397 return (0); 398 } 399 400 /* 401 * The knote may be attached to a different process, which may exit, 402 * leaving nothing for the knote to be attached to. So when the process 403 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 404 * it will be deleted when read out. However, as part of the knote deletion, 405 * this routine is called, so a check is needed to avoid actually performing 406 * a detach, because the original process does not exist any more. 407 */ 408 /* XXX - move to kern_proc.c? */ 409 static void 410 filt_procdetach(struct knote *kn) 411 { 412 struct proc *p; 413 414 p = kn->kn_ptr.p_proc; 415 knlist_remove(&p->p_klist, kn, 0); 416 kn->kn_ptr.p_proc = NULL; 417 } 418 419 /* XXX - move to kern_proc.c? */ 420 static int 421 filt_proc(struct knote *kn, long hint) 422 { 423 struct proc *p; 424 u_int event; 425 426 p = kn->kn_ptr.p_proc; 427 /* Mask off extra data. */ 428 event = (u_int)hint & NOTE_PCTRLMASK; 429 430 /* If the user is interested in this event, record it. */ 431 if (kn->kn_sfflags & event) 432 kn->kn_fflags |= event; 433 434 /* Process is gone, so flag the event as finished. */ 435 if (event == NOTE_EXIT) { 436 if (!(kn->kn_status & KN_DETACHED)) 437 knlist_remove_inevent(&p->p_klist, kn); 438 kn->kn_flags |= EV_EOF | EV_ONESHOT; 439 kn->kn_ptr.p_proc = NULL; 440 if (kn->kn_fflags & NOTE_EXIT) 441 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 442 if (kn->kn_fflags == 0) 443 kn->kn_flags |= EV_DROP; 444 return (1); 445 } 446 447 return (kn->kn_fflags != 0); 448 } 449 450 /* 451 * Called when the process forked. It mostly does the same as the 452 * knote(), activating all knotes registered to be activated when the 453 * process forked. Additionally, for each knote attached to the 454 * parent, check whether user wants to track the new process. If so 455 * attach a new knote to it, and immediately report an event with the 456 * child's pid. 457 */ 458 void 459 knote_fork(struct knlist *list, int pid) 460 { 461 struct kqueue *kq; 462 struct knote *kn; 463 struct kevent kev; 464 int error; 465 466 if (list == NULL) 467 return; 468 list->kl_lock(list->kl_lockarg); 469 470 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 471 /* 472 * XXX - Why do we skip the kn if it is _INFLUX? Does this 473 * mean we will not properly wake up some notes? 474 */ 475 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 476 continue; 477 kq = kn->kn_kq; 478 KQ_LOCK(kq); 479 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 480 KQ_UNLOCK(kq); 481 continue; 482 } 483 484 /* 485 * The same as knote(), activate the event. 486 */ 487 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 488 kn->kn_status |= KN_HASKQLOCK; 489 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 490 KNOTE_ACTIVATE(kn, 1); 491 kn->kn_status &= ~KN_HASKQLOCK; 492 KQ_UNLOCK(kq); 493 continue; 494 } 495 496 /* 497 * The NOTE_TRACK case. In addition to the activation 498 * of the event, we need to register new event to 499 * track the child. Drop the locks in preparation for 500 * the call to kqueue_register(). 501 */ 502 kn->kn_status |= KN_INFLUX; 503 KQ_UNLOCK(kq); 504 list->kl_unlock(list->kl_lockarg); 505 506 /* 507 * Activate existing knote and register a knote with 508 * new process. 509 */ 510 kev.ident = pid; 511 kev.filter = kn->kn_filter; 512 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 513 kev.fflags = kn->kn_sfflags; 514 kev.data = kn->kn_id; /* parent */ 515 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 516 error = kqueue_register(kq, &kev, NULL, 0); 517 if (error) 518 kn->kn_fflags |= NOTE_TRACKERR; 519 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 520 KNOTE_ACTIVATE(kn, 0); 521 KQ_LOCK(kq); 522 kn->kn_status &= ~KN_INFLUX; 523 KQ_UNLOCK_FLUX(kq); 524 list->kl_lock(list->kl_lockarg); 525 } 526 list->kl_unlock(list->kl_lockarg); 527 } 528 529 /* 530 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 531 * interval timer support code. 532 */ 533 534 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \ 535 NOTE_NSECONDS) 536 537 static __inline sbintime_t 538 timer2sbintime(intptr_t data, int flags) 539 { 540 sbintime_t modifier; 541 542 switch (flags & NOTE_TIMER_PRECMASK) { 543 case NOTE_SECONDS: 544 modifier = SBT_1S; 545 break; 546 case NOTE_MSECONDS: /* FALLTHROUGH */ 547 case 0: 548 modifier = SBT_1MS; 549 break; 550 case NOTE_USECONDS: 551 modifier = SBT_1US; 552 break; 553 case NOTE_NSECONDS: 554 modifier = SBT_1NS; 555 break; 556 default: 557 return (-1); 558 } 559 560 #ifdef __LP64__ 561 if (data > SBT_MAX / modifier) 562 return (SBT_MAX); 563 #endif 564 return (modifier * data); 565 } 566 567 static void 568 filt_timerexpire(void *knx) 569 { 570 struct callout *calloutp; 571 struct knote *kn; 572 573 kn = knx; 574 kn->kn_data++; 575 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 576 577 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 578 calloutp = (struct callout *)kn->kn_hook; 579 *kn->kn_ptr.p_nexttime += timer2sbintime(kn->kn_sdata, 580 kn->kn_sfflags); 581 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 582 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 583 } 584 } 585 586 /* 587 * data contains amount of time to sleep 588 */ 589 static int 590 filt_timerattach(struct knote *kn) 591 { 592 struct callout *calloutp; 593 sbintime_t to; 594 unsigned int ncallouts; 595 596 if ((intptr_t)kn->kn_sdata < 0) 597 return (EINVAL); 598 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 599 kn->kn_sdata = 1; 600 /* Only precision unit are supported in flags so far */ 601 if (kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) 602 return (EINVAL); 603 604 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 605 if (to < 0) 606 return (EINVAL); 607 608 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 609 do { 610 if (ncallouts >= kq_calloutmax) 611 return (ENOMEM); 612 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 613 &ncallouts, ncallouts + 1, memory_order_relaxed, 614 memory_order_relaxed)); 615 616 kn->kn_flags |= EV_CLEAR; /* automatically set */ 617 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 618 kn->kn_ptr.p_nexttime = malloc(sizeof(sbintime_t), M_KQUEUE, M_WAITOK); 619 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 620 callout_init(calloutp, 1); 621 kn->kn_hook = calloutp; 622 *kn->kn_ptr.p_nexttime = to + sbinuptime(); 623 callout_reset_sbt_on(calloutp, *kn->kn_ptr.p_nexttime, 0, 624 filt_timerexpire, kn, PCPU_GET(cpuid), C_ABSOLUTE); 625 626 return (0); 627 } 628 629 static void 630 filt_timerdetach(struct knote *kn) 631 { 632 struct callout *calloutp; 633 unsigned int old; 634 635 calloutp = (struct callout *)kn->kn_hook; 636 callout_drain(calloutp); 637 free(calloutp, M_KQUEUE); 638 free(kn->kn_ptr.p_nexttime, M_KQUEUE); 639 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 640 KASSERT(old > 0, ("Number of callouts cannot become negative")); 641 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 642 } 643 644 static int 645 filt_timer(struct knote *kn, long hint) 646 { 647 648 return (kn->kn_data != 0); 649 } 650 651 static int 652 filt_userattach(struct knote *kn) 653 { 654 655 /* 656 * EVFILT_USER knotes are not attached to anything in the kernel. 657 */ 658 kn->kn_hook = NULL; 659 if (kn->kn_fflags & NOTE_TRIGGER) 660 kn->kn_hookid = 1; 661 else 662 kn->kn_hookid = 0; 663 return (0); 664 } 665 666 static void 667 filt_userdetach(__unused struct knote *kn) 668 { 669 670 /* 671 * EVFILT_USER knotes are not attached to anything in the kernel. 672 */ 673 } 674 675 static int 676 filt_user(struct knote *kn, __unused long hint) 677 { 678 679 return (kn->kn_hookid); 680 } 681 682 static void 683 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 684 { 685 u_int ffctrl; 686 687 switch (type) { 688 case EVENT_REGISTER: 689 if (kev->fflags & NOTE_TRIGGER) 690 kn->kn_hookid = 1; 691 692 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 693 kev->fflags &= NOTE_FFLAGSMASK; 694 switch (ffctrl) { 695 case NOTE_FFNOP: 696 break; 697 698 case NOTE_FFAND: 699 kn->kn_sfflags &= kev->fflags; 700 break; 701 702 case NOTE_FFOR: 703 kn->kn_sfflags |= kev->fflags; 704 break; 705 706 case NOTE_FFCOPY: 707 kn->kn_sfflags = kev->fflags; 708 break; 709 710 default: 711 /* XXX Return error? */ 712 break; 713 } 714 kn->kn_sdata = kev->data; 715 if (kev->flags & EV_CLEAR) { 716 kn->kn_hookid = 0; 717 kn->kn_data = 0; 718 kn->kn_fflags = 0; 719 } 720 break; 721 722 case EVENT_PROCESS: 723 *kev = kn->kn_kevent; 724 kev->fflags = kn->kn_sfflags; 725 kev->data = kn->kn_sdata; 726 if (kn->kn_flags & EV_CLEAR) { 727 kn->kn_hookid = 0; 728 kn->kn_data = 0; 729 kn->kn_fflags = 0; 730 } 731 break; 732 733 default: 734 panic("filt_usertouch() - invalid type (%ld)", type); 735 break; 736 } 737 } 738 739 int 740 sys_kqueue(struct thread *td, struct kqueue_args *uap) 741 { 742 743 return (kern_kqueue(td, 0, NULL)); 744 } 745 746 static void 747 kqueue_init(struct kqueue *kq) 748 { 749 750 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 751 TAILQ_INIT(&kq->kq_head); 752 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 753 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 754 } 755 756 int 757 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 758 { 759 struct filedesc *fdp; 760 struct kqueue *kq; 761 struct file *fp; 762 struct proc *p; 763 struct ucred *cred; 764 int fd, error; 765 766 p = td->td_proc; 767 cred = td->td_ucred; 768 crhold(cred); 769 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) { 770 crfree(cred); 771 return (ENOMEM); 772 } 773 774 fdp = p->p_fd; 775 error = falloc_caps(td, &fp, &fd, flags, fcaps); 776 if (error) 777 goto done2; 778 779 /* An extra reference on `fp' has been held for us by falloc(). */ 780 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 781 kqueue_init(kq); 782 kq->kq_fdp = fdp; 783 kq->kq_cred = cred; 784 785 FILEDESC_XLOCK(fdp); 786 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 787 FILEDESC_XUNLOCK(fdp); 788 789 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 790 fdrop(fp, td); 791 792 td->td_retval[0] = fd; 793 done2: 794 if (error != 0) { 795 chgkqcnt(cred->cr_ruidinfo, -1, 0); 796 crfree(cred); 797 } 798 return (error); 799 } 800 801 #ifndef _SYS_SYSPROTO_H_ 802 struct kevent_args { 803 int fd; 804 const struct kevent *changelist; 805 int nchanges; 806 struct kevent *eventlist; 807 int nevents; 808 const struct timespec *timeout; 809 }; 810 #endif 811 int 812 sys_kevent(struct thread *td, struct kevent_args *uap) 813 { 814 struct timespec ts, *tsp; 815 struct kevent_copyops k_ops = { uap, 816 kevent_copyout, 817 kevent_copyin}; 818 int error; 819 #ifdef KTRACE 820 struct uio ktruio; 821 struct iovec ktriov; 822 struct uio *ktruioin = NULL; 823 struct uio *ktruioout = NULL; 824 #endif 825 826 if (uap->timeout != NULL) { 827 error = copyin(uap->timeout, &ts, sizeof(ts)); 828 if (error) 829 return (error); 830 tsp = &ts; 831 } else 832 tsp = NULL; 833 834 #ifdef KTRACE 835 if (KTRPOINT(td, KTR_GENIO)) { 836 ktriov.iov_base = uap->changelist; 837 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 838 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 839 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 840 .uio_td = td }; 841 ktruioin = cloneuio(&ktruio); 842 ktriov.iov_base = uap->eventlist; 843 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 844 ktruioout = cloneuio(&ktruio); 845 } 846 #endif 847 848 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 849 &k_ops, tsp); 850 851 #ifdef KTRACE 852 if (ktruioin != NULL) { 853 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 854 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 855 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 856 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 857 } 858 #endif 859 860 return (error); 861 } 862 863 /* 864 * Copy 'count' items into the destination list pointed to by uap->eventlist. 865 */ 866 static int 867 kevent_copyout(void *arg, struct kevent *kevp, int count) 868 { 869 struct kevent_args *uap; 870 int error; 871 872 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 873 uap = (struct kevent_args *)arg; 874 875 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 876 if (error == 0) 877 uap->eventlist += count; 878 return (error); 879 } 880 881 /* 882 * Copy 'count' items from the list pointed to by uap->changelist. 883 */ 884 static int 885 kevent_copyin(void *arg, struct kevent *kevp, int count) 886 { 887 struct kevent_args *uap; 888 int error; 889 890 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 891 uap = (struct kevent_args *)arg; 892 893 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 894 if (error == 0) 895 uap->changelist += count; 896 return (error); 897 } 898 899 int 900 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 901 struct kevent_copyops *k_ops, const struct timespec *timeout) 902 { 903 cap_rights_t rights; 904 struct file *fp; 905 int error; 906 907 cap_rights_init(&rights); 908 if (nchanges > 0) 909 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 910 if (nevents > 0) 911 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 912 error = fget(td, fd, &rights, &fp); 913 if (error != 0) 914 return (error); 915 916 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 917 fdrop(fp, td); 918 919 return (error); 920 } 921 922 static int 923 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 924 struct kevent_copyops *k_ops, const struct timespec *timeout) 925 { 926 struct kevent keva[KQ_NEVENTS]; 927 struct kevent *kevp, *changes; 928 int i, n, nerrors, error; 929 930 nerrors = 0; 931 while (nchanges > 0) { 932 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 933 error = k_ops->k_copyin(k_ops->arg, keva, n); 934 if (error) 935 return (error); 936 changes = keva; 937 for (i = 0; i < n; i++) { 938 kevp = &changes[i]; 939 if (!kevp->filter) 940 continue; 941 kevp->flags &= ~EV_SYSFLAGS; 942 error = kqueue_register(kq, kevp, td, 1); 943 if (error || (kevp->flags & EV_RECEIPT)) { 944 if (nevents == 0) 945 return (error); 946 kevp->flags = EV_ERROR; 947 kevp->data = error; 948 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 949 nevents--; 950 nerrors++; 951 } 952 } 953 nchanges -= n; 954 } 955 if (nerrors) { 956 td->td_retval[0] = nerrors; 957 return (0); 958 } 959 960 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 961 } 962 963 int 964 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 965 struct kevent_copyops *k_ops, const struct timespec *timeout) 966 { 967 struct kqueue *kq; 968 int error; 969 970 error = kqueue_acquire(fp, &kq); 971 if (error != 0) 972 return (error); 973 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 974 kqueue_release(kq, 0); 975 return (error); 976 } 977 978 /* 979 * Performs a kevent() call on a temporarily created kqueue. This can be 980 * used to perform one-shot polling, similar to poll() and select(). 981 */ 982 int 983 kern_kevent_anonymous(struct thread *td, int nevents, 984 struct kevent_copyops *k_ops) 985 { 986 struct kqueue kq = {}; 987 int error; 988 989 kqueue_init(&kq); 990 kq.kq_refcnt = 1; 991 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 992 kqueue_drain(&kq, td); 993 kqueue_destroy(&kq); 994 return (error); 995 } 996 997 int 998 kqueue_add_filteropts(int filt, struct filterops *filtops) 999 { 1000 int error; 1001 1002 error = 0; 1003 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1004 printf( 1005 "trying to add a filterop that is out of range: %d is beyond %d\n", 1006 ~filt, EVFILT_SYSCOUNT); 1007 return EINVAL; 1008 } 1009 mtx_lock(&filterops_lock); 1010 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1011 sysfilt_ops[~filt].for_fop != NULL) 1012 error = EEXIST; 1013 else { 1014 sysfilt_ops[~filt].for_fop = filtops; 1015 sysfilt_ops[~filt].for_refcnt = 0; 1016 } 1017 mtx_unlock(&filterops_lock); 1018 1019 return (error); 1020 } 1021 1022 int 1023 kqueue_del_filteropts(int filt) 1024 { 1025 int error; 1026 1027 error = 0; 1028 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1029 return EINVAL; 1030 1031 mtx_lock(&filterops_lock); 1032 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1033 sysfilt_ops[~filt].for_fop == NULL) 1034 error = EINVAL; 1035 else if (sysfilt_ops[~filt].for_refcnt != 0) 1036 error = EBUSY; 1037 else { 1038 sysfilt_ops[~filt].for_fop = &null_filtops; 1039 sysfilt_ops[~filt].for_refcnt = 0; 1040 } 1041 mtx_unlock(&filterops_lock); 1042 1043 return error; 1044 } 1045 1046 static struct filterops * 1047 kqueue_fo_find(int filt) 1048 { 1049 1050 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1051 return NULL; 1052 1053 if (sysfilt_ops[~filt].for_nolock) 1054 return sysfilt_ops[~filt].for_fop; 1055 1056 mtx_lock(&filterops_lock); 1057 sysfilt_ops[~filt].for_refcnt++; 1058 if (sysfilt_ops[~filt].for_fop == NULL) 1059 sysfilt_ops[~filt].for_fop = &null_filtops; 1060 mtx_unlock(&filterops_lock); 1061 1062 return sysfilt_ops[~filt].for_fop; 1063 } 1064 1065 static void 1066 kqueue_fo_release(int filt) 1067 { 1068 1069 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1070 return; 1071 1072 if (sysfilt_ops[~filt].for_nolock) 1073 return; 1074 1075 mtx_lock(&filterops_lock); 1076 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1077 ("filter object refcount not valid on release")); 1078 sysfilt_ops[~filt].for_refcnt--; 1079 mtx_unlock(&filterops_lock); 1080 } 1081 1082 /* 1083 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1084 * influence if memory allocation should wait. Make sure it is 0 if you 1085 * hold any mutexes. 1086 */ 1087 static int 1088 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1089 { 1090 struct filterops *fops; 1091 struct file *fp; 1092 struct knote *kn, *tkn; 1093 cap_rights_t rights; 1094 int error, filt, event; 1095 int haskqglobal, filedesc_unlock; 1096 1097 fp = NULL; 1098 kn = NULL; 1099 error = 0; 1100 haskqglobal = 0; 1101 filedesc_unlock = 0; 1102 1103 filt = kev->filter; 1104 fops = kqueue_fo_find(filt); 1105 if (fops == NULL) 1106 return EINVAL; 1107 1108 if (kev->flags & EV_ADD) 1109 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1110 else 1111 tkn = NULL; 1112 1113 findkn: 1114 if (fops->f_isfd) { 1115 KASSERT(td != NULL, ("td is NULL")); 1116 error = fget(td, kev->ident, 1117 cap_rights_init(&rights, CAP_EVENT), &fp); 1118 if (error) 1119 goto done; 1120 1121 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1122 kev->ident, 0) != 0) { 1123 /* try again */ 1124 fdrop(fp, td); 1125 fp = NULL; 1126 error = kqueue_expand(kq, fops, kev->ident, waitok); 1127 if (error) 1128 goto done; 1129 goto findkn; 1130 } 1131 1132 if (fp->f_type == DTYPE_KQUEUE) { 1133 /* 1134 * if we add some inteligence about what we are doing, 1135 * we should be able to support events on ourselves. 1136 * We need to know when we are doing this to prevent 1137 * getting both the knlist lock and the kq lock since 1138 * they are the same thing. 1139 */ 1140 if (fp->f_data == kq) { 1141 error = EINVAL; 1142 goto done; 1143 } 1144 1145 /* 1146 * Pre-lock the filedesc before the global 1147 * lock mutex, see the comment in 1148 * kqueue_close(). 1149 */ 1150 FILEDESC_XLOCK(td->td_proc->p_fd); 1151 filedesc_unlock = 1; 1152 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1153 } 1154 1155 KQ_LOCK(kq); 1156 if (kev->ident < kq->kq_knlistsize) { 1157 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1158 if (kev->filter == kn->kn_filter) 1159 break; 1160 } 1161 } else { 1162 if ((kev->flags & EV_ADD) == EV_ADD) 1163 kqueue_expand(kq, fops, kev->ident, waitok); 1164 1165 KQ_LOCK(kq); 1166 if (kq->kq_knhashmask != 0) { 1167 struct klist *list; 1168 1169 list = &kq->kq_knhash[ 1170 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1171 SLIST_FOREACH(kn, list, kn_link) 1172 if (kev->ident == kn->kn_id && 1173 kev->filter == kn->kn_filter) 1174 break; 1175 } 1176 } 1177 1178 /* knote is in the process of changing, wait for it to stablize. */ 1179 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1180 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1181 if (filedesc_unlock) { 1182 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1183 filedesc_unlock = 0; 1184 } 1185 kq->kq_state |= KQ_FLUXWAIT; 1186 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1187 if (fp != NULL) { 1188 fdrop(fp, td); 1189 fp = NULL; 1190 } 1191 goto findkn; 1192 } 1193 1194 /* 1195 * kn now contains the matching knote, or NULL if no match 1196 */ 1197 if (kn == NULL) { 1198 if (kev->flags & EV_ADD) { 1199 kn = tkn; 1200 tkn = NULL; 1201 if (kn == NULL) { 1202 KQ_UNLOCK(kq); 1203 error = ENOMEM; 1204 goto done; 1205 } 1206 kn->kn_fp = fp; 1207 kn->kn_kq = kq; 1208 kn->kn_fop = fops; 1209 /* 1210 * apply reference counts to knote structure, and 1211 * do not release it at the end of this routine. 1212 */ 1213 fops = NULL; 1214 fp = NULL; 1215 1216 kn->kn_sfflags = kev->fflags; 1217 kn->kn_sdata = kev->data; 1218 kev->fflags = 0; 1219 kev->data = 0; 1220 kn->kn_kevent = *kev; 1221 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1222 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1223 kn->kn_status = KN_INFLUX|KN_DETACHED; 1224 1225 error = knote_attach(kn, kq); 1226 KQ_UNLOCK(kq); 1227 if (error != 0) { 1228 tkn = kn; 1229 goto done; 1230 } 1231 1232 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1233 knote_drop(kn, td); 1234 goto done; 1235 } 1236 KN_LIST_LOCK(kn); 1237 goto done_ev_add; 1238 } else { 1239 /* No matching knote and the EV_ADD flag is not set. */ 1240 KQ_UNLOCK(kq); 1241 error = ENOENT; 1242 goto done; 1243 } 1244 } 1245 1246 if (kev->flags & EV_DELETE) { 1247 kn->kn_status |= KN_INFLUX; 1248 KQ_UNLOCK(kq); 1249 if (!(kn->kn_status & KN_DETACHED)) 1250 kn->kn_fop->f_detach(kn); 1251 knote_drop(kn, td); 1252 goto done; 1253 } 1254 1255 if (kev->flags & EV_FORCEONESHOT) { 1256 kn->kn_flags |= EV_ONESHOT; 1257 KNOTE_ACTIVATE(kn, 1); 1258 } 1259 1260 /* 1261 * The user may change some filter values after the initial EV_ADD, 1262 * but doing so will not reset any filter which has already been 1263 * triggered. 1264 */ 1265 kn->kn_status |= KN_INFLUX | KN_SCAN; 1266 KQ_UNLOCK(kq); 1267 KN_LIST_LOCK(kn); 1268 kn->kn_kevent.udata = kev->udata; 1269 if (!fops->f_isfd && fops->f_touch != NULL) { 1270 fops->f_touch(kn, kev, EVENT_REGISTER); 1271 } else { 1272 kn->kn_sfflags = kev->fflags; 1273 kn->kn_sdata = kev->data; 1274 } 1275 1276 /* 1277 * We can get here with kn->kn_knlist == NULL. This can happen when 1278 * the initial attach event decides that the event is "completed" 1279 * already. i.e. filt_procattach is called on a zombie process. It 1280 * will call filt_proc which will remove it from the list, and NULL 1281 * kn_knlist. 1282 */ 1283 done_ev_add: 1284 if ((kev->flags & EV_DISABLE) && 1285 ((kn->kn_status & KN_DISABLED) == 0)) { 1286 kn->kn_status |= KN_DISABLED; 1287 } 1288 1289 if ((kn->kn_status & KN_DISABLED) == 0) 1290 event = kn->kn_fop->f_event(kn, 0); 1291 else 1292 event = 0; 1293 KQ_LOCK(kq); 1294 if (event) 1295 KNOTE_ACTIVATE(kn, 1); 1296 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1297 KN_LIST_UNLOCK(kn); 1298 1299 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1300 kn->kn_status &= ~KN_DISABLED; 1301 if ((kn->kn_status & KN_ACTIVE) && 1302 ((kn->kn_status & KN_QUEUED) == 0)) 1303 knote_enqueue(kn); 1304 } 1305 KQ_UNLOCK_FLUX(kq); 1306 1307 done: 1308 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1309 if (filedesc_unlock) 1310 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1311 if (fp != NULL) 1312 fdrop(fp, td); 1313 if (tkn != NULL) 1314 knote_free(tkn); 1315 if (fops != NULL) 1316 kqueue_fo_release(filt); 1317 return (error); 1318 } 1319 1320 static int 1321 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1322 { 1323 int error; 1324 struct kqueue *kq; 1325 1326 error = 0; 1327 1328 kq = fp->f_data; 1329 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1330 return (EBADF); 1331 *kqp = kq; 1332 KQ_LOCK(kq); 1333 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1334 KQ_UNLOCK(kq); 1335 return (EBADF); 1336 } 1337 kq->kq_refcnt++; 1338 KQ_UNLOCK(kq); 1339 1340 return error; 1341 } 1342 1343 static void 1344 kqueue_release(struct kqueue *kq, int locked) 1345 { 1346 if (locked) 1347 KQ_OWNED(kq); 1348 else 1349 KQ_LOCK(kq); 1350 kq->kq_refcnt--; 1351 if (kq->kq_refcnt == 1) 1352 wakeup(&kq->kq_refcnt); 1353 if (!locked) 1354 KQ_UNLOCK(kq); 1355 } 1356 1357 static void 1358 kqueue_schedtask(struct kqueue *kq) 1359 { 1360 1361 KQ_OWNED(kq); 1362 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1363 ("scheduling kqueue task while draining")); 1364 1365 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1366 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1367 kq->kq_state |= KQ_TASKSCHED; 1368 } 1369 } 1370 1371 /* 1372 * Expand the kq to make sure we have storage for fops/ident pair. 1373 * 1374 * Return 0 on success (or no work necessary), return errno on failure. 1375 * 1376 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1377 * If kqueue_register is called from a non-fd context, there usually/should 1378 * be no locks held. 1379 */ 1380 static int 1381 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1382 int waitok) 1383 { 1384 struct klist *list, *tmp_knhash, *to_free; 1385 u_long tmp_knhashmask; 1386 int size; 1387 int fd; 1388 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1389 1390 KQ_NOTOWNED(kq); 1391 1392 to_free = NULL; 1393 if (fops->f_isfd) { 1394 fd = ident; 1395 if (kq->kq_knlistsize <= fd) { 1396 size = kq->kq_knlistsize; 1397 while (size <= fd) 1398 size += KQEXTENT; 1399 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1400 if (list == NULL) 1401 return ENOMEM; 1402 KQ_LOCK(kq); 1403 if (kq->kq_knlistsize > fd) { 1404 to_free = list; 1405 list = NULL; 1406 } else { 1407 if (kq->kq_knlist != NULL) { 1408 bcopy(kq->kq_knlist, list, 1409 kq->kq_knlistsize * sizeof(*list)); 1410 to_free = kq->kq_knlist; 1411 kq->kq_knlist = NULL; 1412 } 1413 bzero((caddr_t)list + 1414 kq->kq_knlistsize * sizeof(*list), 1415 (size - kq->kq_knlistsize) * sizeof(*list)); 1416 kq->kq_knlistsize = size; 1417 kq->kq_knlist = list; 1418 } 1419 KQ_UNLOCK(kq); 1420 } 1421 } else { 1422 if (kq->kq_knhashmask == 0) { 1423 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1424 &tmp_knhashmask); 1425 if (tmp_knhash == NULL) 1426 return ENOMEM; 1427 KQ_LOCK(kq); 1428 if (kq->kq_knhashmask == 0) { 1429 kq->kq_knhash = tmp_knhash; 1430 kq->kq_knhashmask = tmp_knhashmask; 1431 } else { 1432 to_free = tmp_knhash; 1433 } 1434 KQ_UNLOCK(kq); 1435 } 1436 } 1437 free(to_free, M_KQUEUE); 1438 1439 KQ_NOTOWNED(kq); 1440 return 0; 1441 } 1442 1443 static void 1444 kqueue_task(void *arg, int pending) 1445 { 1446 struct kqueue *kq; 1447 int haskqglobal; 1448 1449 haskqglobal = 0; 1450 kq = arg; 1451 1452 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1453 KQ_LOCK(kq); 1454 1455 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1456 1457 kq->kq_state &= ~KQ_TASKSCHED; 1458 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1459 wakeup(&kq->kq_state); 1460 } 1461 KQ_UNLOCK(kq); 1462 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1463 } 1464 1465 /* 1466 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1467 * We treat KN_MARKER knotes as if they are INFLUX. 1468 */ 1469 static int 1470 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1471 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1472 { 1473 struct kevent *kevp; 1474 struct knote *kn, *marker; 1475 sbintime_t asbt, rsbt; 1476 int count, error, haskqglobal, influx, nkev, touch; 1477 1478 count = maxevents; 1479 nkev = 0; 1480 error = 0; 1481 haskqglobal = 0; 1482 1483 if (maxevents == 0) 1484 goto done_nl; 1485 1486 rsbt = 0; 1487 if (tsp != NULL) { 1488 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1489 tsp->tv_nsec >= 1000000000) { 1490 error = EINVAL; 1491 goto done_nl; 1492 } 1493 if (timespecisset(tsp)) { 1494 if (tsp->tv_sec <= INT32_MAX) { 1495 rsbt = tstosbt(*tsp); 1496 if (TIMESEL(&asbt, rsbt)) 1497 asbt += tc_tick_sbt; 1498 if (asbt <= SBT_MAX - rsbt) 1499 asbt += rsbt; 1500 else 1501 asbt = 0; 1502 rsbt >>= tc_precexp; 1503 } else 1504 asbt = 0; 1505 } else 1506 asbt = -1; 1507 } else 1508 asbt = 0; 1509 marker = knote_alloc(1); 1510 if (marker == NULL) { 1511 error = ENOMEM; 1512 goto done_nl; 1513 } 1514 marker->kn_status = KN_MARKER; 1515 KQ_LOCK(kq); 1516 1517 retry: 1518 kevp = keva; 1519 if (kq->kq_count == 0) { 1520 if (asbt == -1) { 1521 error = EWOULDBLOCK; 1522 } else { 1523 kq->kq_state |= KQ_SLEEP; 1524 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1525 "kqread", asbt, rsbt, C_ABSOLUTE); 1526 } 1527 if (error == 0) 1528 goto retry; 1529 /* don't restart after signals... */ 1530 if (error == ERESTART) 1531 error = EINTR; 1532 else if (error == EWOULDBLOCK) 1533 error = 0; 1534 goto done; 1535 } 1536 1537 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1538 influx = 0; 1539 while (count) { 1540 KQ_OWNED(kq); 1541 kn = TAILQ_FIRST(&kq->kq_head); 1542 1543 if ((kn->kn_status == KN_MARKER && kn != marker) || 1544 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1545 if (influx) { 1546 influx = 0; 1547 KQ_FLUX_WAKEUP(kq); 1548 } 1549 kq->kq_state |= KQ_FLUXWAIT; 1550 error = msleep(kq, &kq->kq_lock, PSOCK, 1551 "kqflxwt", 0); 1552 continue; 1553 } 1554 1555 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1556 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1557 kn->kn_status &= ~KN_QUEUED; 1558 kq->kq_count--; 1559 continue; 1560 } 1561 if (kn == marker) { 1562 KQ_FLUX_WAKEUP(kq); 1563 if (count == maxevents) 1564 goto retry; 1565 goto done; 1566 } 1567 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1568 ("KN_INFLUX set when not suppose to be")); 1569 1570 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1571 kn->kn_status &= ~KN_QUEUED; 1572 kn->kn_status |= KN_INFLUX; 1573 kq->kq_count--; 1574 KQ_UNLOCK(kq); 1575 /* 1576 * We don't need to lock the list since we've marked 1577 * it _INFLUX. 1578 */ 1579 if (!(kn->kn_status & KN_DETACHED)) 1580 kn->kn_fop->f_detach(kn); 1581 knote_drop(kn, td); 1582 KQ_LOCK(kq); 1583 continue; 1584 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1585 kn->kn_status &= ~KN_QUEUED; 1586 kn->kn_status |= KN_INFLUX; 1587 kq->kq_count--; 1588 KQ_UNLOCK(kq); 1589 /* 1590 * We don't need to lock the list since we've marked 1591 * it _INFLUX. 1592 */ 1593 *kevp = kn->kn_kevent; 1594 if (!(kn->kn_status & KN_DETACHED)) 1595 kn->kn_fop->f_detach(kn); 1596 knote_drop(kn, td); 1597 KQ_LOCK(kq); 1598 kn = NULL; 1599 } else { 1600 kn->kn_status |= KN_INFLUX | KN_SCAN; 1601 KQ_UNLOCK(kq); 1602 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1603 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1604 KN_LIST_LOCK(kn); 1605 if (kn->kn_fop->f_event(kn, 0) == 0) { 1606 KQ_LOCK(kq); 1607 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1608 kn->kn_status &= 1609 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1610 KN_SCAN); 1611 kq->kq_count--; 1612 KN_LIST_UNLOCK(kn); 1613 influx = 1; 1614 continue; 1615 } 1616 touch = (!kn->kn_fop->f_isfd && 1617 kn->kn_fop->f_touch != NULL); 1618 if (touch) 1619 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1620 else 1621 *kevp = kn->kn_kevent; 1622 KQ_LOCK(kq); 1623 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1624 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1625 /* 1626 * Manually clear knotes who weren't 1627 * 'touch'ed. 1628 */ 1629 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1630 kn->kn_data = 0; 1631 kn->kn_fflags = 0; 1632 } 1633 if (kn->kn_flags & EV_DISPATCH) 1634 kn->kn_status |= KN_DISABLED; 1635 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1636 kq->kq_count--; 1637 } else 1638 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1639 1640 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1641 KN_LIST_UNLOCK(kn); 1642 influx = 1; 1643 } 1644 1645 /* we are returning a copy to the user */ 1646 kevp++; 1647 nkev++; 1648 count--; 1649 1650 if (nkev == KQ_NEVENTS) { 1651 influx = 0; 1652 KQ_UNLOCK_FLUX(kq); 1653 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1654 nkev = 0; 1655 kevp = keva; 1656 KQ_LOCK(kq); 1657 if (error) 1658 break; 1659 } 1660 } 1661 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1662 done: 1663 KQ_OWNED(kq); 1664 KQ_UNLOCK_FLUX(kq); 1665 knote_free(marker); 1666 done_nl: 1667 KQ_NOTOWNED(kq); 1668 if (nkev != 0) 1669 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1670 td->td_retval[0] = maxevents - count; 1671 return (error); 1672 } 1673 1674 /*ARGSUSED*/ 1675 static int 1676 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1677 struct ucred *active_cred, struct thread *td) 1678 { 1679 /* 1680 * Enabling sigio causes two major problems: 1681 * 1) infinite recursion: 1682 * Synopsys: kevent is being used to track signals and have FIOASYNC 1683 * set. On receipt of a signal this will cause a kqueue to recurse 1684 * into itself over and over. Sending the sigio causes the kqueue 1685 * to become ready, which in turn posts sigio again, forever. 1686 * Solution: this can be solved by setting a flag in the kqueue that 1687 * we have a SIGIO in progress. 1688 * 2) locking problems: 1689 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1690 * us above the proc and pgrp locks. 1691 * Solution: Post a signal using an async mechanism, being sure to 1692 * record a generation count in the delivery so that we do not deliver 1693 * a signal to the wrong process. 1694 * 1695 * Note, these two mechanisms are somewhat mutually exclusive! 1696 */ 1697 #if 0 1698 struct kqueue *kq; 1699 1700 kq = fp->f_data; 1701 switch (cmd) { 1702 case FIOASYNC: 1703 if (*(int *)data) { 1704 kq->kq_state |= KQ_ASYNC; 1705 } else { 1706 kq->kq_state &= ~KQ_ASYNC; 1707 } 1708 return (0); 1709 1710 case FIOSETOWN: 1711 return (fsetown(*(int *)data, &kq->kq_sigio)); 1712 1713 case FIOGETOWN: 1714 *(int *)data = fgetown(&kq->kq_sigio); 1715 return (0); 1716 } 1717 #endif 1718 1719 return (ENOTTY); 1720 } 1721 1722 /*ARGSUSED*/ 1723 static int 1724 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1725 struct thread *td) 1726 { 1727 struct kqueue *kq; 1728 int revents = 0; 1729 int error; 1730 1731 if ((error = kqueue_acquire(fp, &kq))) 1732 return POLLERR; 1733 1734 KQ_LOCK(kq); 1735 if (events & (POLLIN | POLLRDNORM)) { 1736 if (kq->kq_count) { 1737 revents |= events & (POLLIN | POLLRDNORM); 1738 } else { 1739 selrecord(td, &kq->kq_sel); 1740 if (SEL_WAITING(&kq->kq_sel)) 1741 kq->kq_state |= KQ_SEL; 1742 } 1743 } 1744 kqueue_release(kq, 1); 1745 KQ_UNLOCK(kq); 1746 return (revents); 1747 } 1748 1749 /*ARGSUSED*/ 1750 static int 1751 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1752 struct thread *td) 1753 { 1754 1755 bzero((void *)st, sizeof *st); 1756 /* 1757 * We no longer return kq_count because the unlocked value is useless. 1758 * If you spent all this time getting the count, why not spend your 1759 * syscall better by calling kevent? 1760 * 1761 * XXX - This is needed for libc_r. 1762 */ 1763 st->st_mode = S_IFIFO; 1764 return (0); 1765 } 1766 1767 static void 1768 kqueue_drain(struct kqueue *kq, struct thread *td) 1769 { 1770 struct knote *kn; 1771 int i; 1772 1773 KQ_LOCK(kq); 1774 1775 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1776 ("kqueue already closing")); 1777 kq->kq_state |= KQ_CLOSING; 1778 if (kq->kq_refcnt > 1) 1779 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1780 1781 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1782 1783 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1784 ("kqueue's knlist not empty")); 1785 1786 for (i = 0; i < kq->kq_knlistsize; i++) { 1787 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1788 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1789 kq->kq_state |= KQ_FLUXWAIT; 1790 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1791 continue; 1792 } 1793 kn->kn_status |= KN_INFLUX; 1794 KQ_UNLOCK(kq); 1795 if (!(kn->kn_status & KN_DETACHED)) 1796 kn->kn_fop->f_detach(kn); 1797 knote_drop(kn, td); 1798 KQ_LOCK(kq); 1799 } 1800 } 1801 if (kq->kq_knhashmask != 0) { 1802 for (i = 0; i <= kq->kq_knhashmask; i++) { 1803 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1804 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1805 kq->kq_state |= KQ_FLUXWAIT; 1806 msleep(kq, &kq->kq_lock, PSOCK, 1807 "kqclo2", 0); 1808 continue; 1809 } 1810 kn->kn_status |= KN_INFLUX; 1811 KQ_UNLOCK(kq); 1812 if (!(kn->kn_status & KN_DETACHED)) 1813 kn->kn_fop->f_detach(kn); 1814 knote_drop(kn, td); 1815 KQ_LOCK(kq); 1816 } 1817 } 1818 } 1819 1820 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1821 kq->kq_state |= KQ_TASKDRAIN; 1822 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1823 } 1824 1825 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1826 selwakeuppri(&kq->kq_sel, PSOCK); 1827 if (!SEL_WAITING(&kq->kq_sel)) 1828 kq->kq_state &= ~KQ_SEL; 1829 } 1830 1831 KQ_UNLOCK(kq); 1832 } 1833 1834 static void 1835 kqueue_destroy(struct kqueue *kq) 1836 { 1837 1838 KASSERT(kq->kq_fdp == NULL, 1839 ("kqueue still attached to a file descriptor")); 1840 seldrain(&kq->kq_sel); 1841 knlist_destroy(&kq->kq_sel.si_note); 1842 mtx_destroy(&kq->kq_lock); 1843 1844 if (kq->kq_knhash != NULL) 1845 free(kq->kq_knhash, M_KQUEUE); 1846 if (kq->kq_knlist != NULL) 1847 free(kq->kq_knlist, M_KQUEUE); 1848 1849 funsetown(&kq->kq_sigio); 1850 } 1851 1852 /*ARGSUSED*/ 1853 static int 1854 kqueue_close(struct file *fp, struct thread *td) 1855 { 1856 struct kqueue *kq = fp->f_data; 1857 struct filedesc *fdp; 1858 int error; 1859 int filedesc_unlock; 1860 1861 if ((error = kqueue_acquire(fp, &kq))) 1862 return error; 1863 kqueue_drain(kq, td); 1864 1865 /* 1866 * We could be called due to the knote_drop() doing fdrop(), 1867 * called from kqueue_register(). In this case the global 1868 * lock is owned, and filedesc sx is locked before, to not 1869 * take the sleepable lock after non-sleepable. 1870 */ 1871 fdp = kq->kq_fdp; 1872 kq->kq_fdp = NULL; 1873 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1874 FILEDESC_XLOCK(fdp); 1875 filedesc_unlock = 1; 1876 } else 1877 filedesc_unlock = 0; 1878 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1879 if (filedesc_unlock) 1880 FILEDESC_XUNLOCK(fdp); 1881 1882 kqueue_destroy(kq); 1883 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1884 crfree(kq->kq_cred); 1885 free(kq, M_KQUEUE); 1886 fp->f_data = NULL; 1887 1888 return (0); 1889 } 1890 1891 static int 1892 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 1893 { 1894 1895 kif->kf_type = KF_TYPE_KQUEUE; 1896 return (0); 1897 } 1898 1899 static void 1900 kqueue_wakeup(struct kqueue *kq) 1901 { 1902 KQ_OWNED(kq); 1903 1904 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1905 kq->kq_state &= ~KQ_SLEEP; 1906 wakeup(kq); 1907 } 1908 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1909 selwakeuppri(&kq->kq_sel, PSOCK); 1910 if (!SEL_WAITING(&kq->kq_sel)) 1911 kq->kq_state &= ~KQ_SEL; 1912 } 1913 if (!knlist_empty(&kq->kq_sel.si_note)) 1914 kqueue_schedtask(kq); 1915 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1916 pgsigio(&kq->kq_sigio, SIGIO, 0); 1917 } 1918 } 1919 1920 /* 1921 * Walk down a list of knotes, activating them if their event has triggered. 1922 * 1923 * There is a possibility to optimize in the case of one kq watching another. 1924 * Instead of scheduling a task to wake it up, you could pass enough state 1925 * down the chain to make up the parent kqueue. Make this code functional 1926 * first. 1927 */ 1928 void 1929 knote(struct knlist *list, long hint, int lockflags) 1930 { 1931 struct kqueue *kq; 1932 struct knote *kn; 1933 int error; 1934 1935 if (list == NULL) 1936 return; 1937 1938 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1939 1940 if ((lockflags & KNF_LISTLOCKED) == 0) 1941 list->kl_lock(list->kl_lockarg); 1942 1943 /* 1944 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1945 * the kqueue scheduling, but this will introduce four 1946 * lock/unlock's for each knote to test. If we do, continue to use 1947 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1948 * only safe if you want to remove the current item, which we are 1949 * not doing. 1950 */ 1951 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1952 kq = kn->kn_kq; 1953 KQ_LOCK(kq); 1954 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1955 /* 1956 * Do not process the influx notes, except for 1957 * the influx coming from the kq unlock in the 1958 * kqueue_scan(). In the later case, we do 1959 * not interfere with the scan, since the code 1960 * fragment in kqueue_scan() locks the knlist, 1961 * and cannot proceed until we finished. 1962 */ 1963 KQ_UNLOCK(kq); 1964 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1965 kn->kn_status |= KN_INFLUX; 1966 KQ_UNLOCK(kq); 1967 error = kn->kn_fop->f_event(kn, hint); 1968 KQ_LOCK(kq); 1969 kn->kn_status &= ~KN_INFLUX; 1970 if (error) 1971 KNOTE_ACTIVATE(kn, 1); 1972 KQ_UNLOCK_FLUX(kq); 1973 } else { 1974 kn->kn_status |= KN_HASKQLOCK; 1975 if (kn->kn_fop->f_event(kn, hint)) 1976 KNOTE_ACTIVATE(kn, 1); 1977 kn->kn_status &= ~KN_HASKQLOCK; 1978 KQ_UNLOCK(kq); 1979 } 1980 } 1981 if ((lockflags & KNF_LISTLOCKED) == 0) 1982 list->kl_unlock(list->kl_lockarg); 1983 } 1984 1985 /* 1986 * add a knote to a knlist 1987 */ 1988 void 1989 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1990 { 1991 KNL_ASSERT_LOCK(knl, islocked); 1992 KQ_NOTOWNED(kn->kn_kq); 1993 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1994 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1995 if (!islocked) 1996 knl->kl_lock(knl->kl_lockarg); 1997 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1998 if (!islocked) 1999 knl->kl_unlock(knl->kl_lockarg); 2000 KQ_LOCK(kn->kn_kq); 2001 kn->kn_knlist = knl; 2002 kn->kn_status &= ~KN_DETACHED; 2003 KQ_UNLOCK(kn->kn_kq); 2004 } 2005 2006 static void 2007 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 2008 { 2009 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 2010 KNL_ASSERT_LOCK(knl, knlislocked); 2011 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2012 if (!kqislocked) 2013 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 2014 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 2015 if (!knlislocked) 2016 knl->kl_lock(knl->kl_lockarg); 2017 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2018 kn->kn_knlist = NULL; 2019 if (!knlislocked) 2020 knl->kl_unlock(knl->kl_lockarg); 2021 if (!kqislocked) 2022 KQ_LOCK(kn->kn_kq); 2023 kn->kn_status |= KN_DETACHED; 2024 if (!kqislocked) 2025 KQ_UNLOCK(kn->kn_kq); 2026 } 2027 2028 /* 2029 * remove knote from the specified knlist 2030 */ 2031 void 2032 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2033 { 2034 2035 knlist_remove_kq(knl, kn, islocked, 0); 2036 } 2037 2038 /* 2039 * remove knote from the specified knlist while in f_event handler. 2040 */ 2041 void 2042 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 2043 { 2044 2045 knlist_remove_kq(knl, kn, 1, 2046 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 2047 } 2048 2049 int 2050 knlist_empty(struct knlist *knl) 2051 { 2052 2053 KNL_ASSERT_LOCKED(knl); 2054 return SLIST_EMPTY(&knl->kl_list); 2055 } 2056 2057 static struct mtx knlist_lock; 2058 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2059 MTX_DEF); 2060 static void knlist_mtx_lock(void *arg); 2061 static void knlist_mtx_unlock(void *arg); 2062 2063 static void 2064 knlist_mtx_lock(void *arg) 2065 { 2066 2067 mtx_lock((struct mtx *)arg); 2068 } 2069 2070 static void 2071 knlist_mtx_unlock(void *arg) 2072 { 2073 2074 mtx_unlock((struct mtx *)arg); 2075 } 2076 2077 static void 2078 knlist_mtx_assert_locked(void *arg) 2079 { 2080 2081 mtx_assert((struct mtx *)arg, MA_OWNED); 2082 } 2083 2084 static void 2085 knlist_mtx_assert_unlocked(void *arg) 2086 { 2087 2088 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2089 } 2090 2091 static void 2092 knlist_rw_rlock(void *arg) 2093 { 2094 2095 rw_rlock((struct rwlock *)arg); 2096 } 2097 2098 static void 2099 knlist_rw_runlock(void *arg) 2100 { 2101 2102 rw_runlock((struct rwlock *)arg); 2103 } 2104 2105 static void 2106 knlist_rw_assert_locked(void *arg) 2107 { 2108 2109 rw_assert((struct rwlock *)arg, RA_LOCKED); 2110 } 2111 2112 static void 2113 knlist_rw_assert_unlocked(void *arg) 2114 { 2115 2116 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2117 } 2118 2119 void 2120 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2121 void (*kl_unlock)(void *), 2122 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2123 { 2124 2125 if (lock == NULL) 2126 knl->kl_lockarg = &knlist_lock; 2127 else 2128 knl->kl_lockarg = lock; 2129 2130 if (kl_lock == NULL) 2131 knl->kl_lock = knlist_mtx_lock; 2132 else 2133 knl->kl_lock = kl_lock; 2134 if (kl_unlock == NULL) 2135 knl->kl_unlock = knlist_mtx_unlock; 2136 else 2137 knl->kl_unlock = kl_unlock; 2138 if (kl_assert_locked == NULL) 2139 knl->kl_assert_locked = knlist_mtx_assert_locked; 2140 else 2141 knl->kl_assert_locked = kl_assert_locked; 2142 if (kl_assert_unlocked == NULL) 2143 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2144 else 2145 knl->kl_assert_unlocked = kl_assert_unlocked; 2146 2147 SLIST_INIT(&knl->kl_list); 2148 } 2149 2150 void 2151 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2152 { 2153 2154 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2155 } 2156 2157 void 2158 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2159 { 2160 2161 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2162 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2163 } 2164 2165 void 2166 knlist_destroy(struct knlist *knl) 2167 { 2168 2169 #ifdef INVARIANTS 2170 /* 2171 * if we run across this error, we need to find the offending 2172 * driver and have it call knlist_clear or knlist_delete. 2173 */ 2174 if (!SLIST_EMPTY(&knl->kl_list)) 2175 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2176 #endif 2177 2178 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2179 SLIST_INIT(&knl->kl_list); 2180 } 2181 2182 /* 2183 * Even if we are locked, we may need to drop the lock to allow any influx 2184 * knotes time to "settle". 2185 */ 2186 void 2187 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2188 { 2189 struct knote *kn, *kn2; 2190 struct kqueue *kq; 2191 2192 if (islocked) 2193 KNL_ASSERT_LOCKED(knl); 2194 else { 2195 KNL_ASSERT_UNLOCKED(knl); 2196 again: /* need to reacquire lock since we have dropped it */ 2197 knl->kl_lock(knl->kl_lockarg); 2198 } 2199 2200 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2201 kq = kn->kn_kq; 2202 KQ_LOCK(kq); 2203 if ((kn->kn_status & KN_INFLUX)) { 2204 KQ_UNLOCK(kq); 2205 continue; 2206 } 2207 knlist_remove_kq(knl, kn, 1, 1); 2208 if (killkn) { 2209 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2210 KQ_UNLOCK(kq); 2211 knote_drop(kn, td); 2212 } else { 2213 /* Make sure cleared knotes disappear soon */ 2214 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2215 KQ_UNLOCK(kq); 2216 } 2217 kq = NULL; 2218 } 2219 2220 if (!SLIST_EMPTY(&knl->kl_list)) { 2221 /* there are still KN_INFLUX remaining */ 2222 kn = SLIST_FIRST(&knl->kl_list); 2223 kq = kn->kn_kq; 2224 KQ_LOCK(kq); 2225 KASSERT(kn->kn_status & KN_INFLUX, 2226 ("knote removed w/o list lock")); 2227 knl->kl_unlock(knl->kl_lockarg); 2228 kq->kq_state |= KQ_FLUXWAIT; 2229 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2230 kq = NULL; 2231 goto again; 2232 } 2233 2234 if (islocked) 2235 KNL_ASSERT_LOCKED(knl); 2236 else { 2237 knl->kl_unlock(knl->kl_lockarg); 2238 KNL_ASSERT_UNLOCKED(knl); 2239 } 2240 } 2241 2242 /* 2243 * Remove all knotes referencing a specified fd must be called with FILEDESC 2244 * lock. This prevents a race where a new fd comes along and occupies the 2245 * entry and we attach a knote to the fd. 2246 */ 2247 void 2248 knote_fdclose(struct thread *td, int fd) 2249 { 2250 struct filedesc *fdp = td->td_proc->p_fd; 2251 struct kqueue *kq; 2252 struct knote *kn; 2253 int influx; 2254 2255 FILEDESC_XLOCK_ASSERT(fdp); 2256 2257 /* 2258 * We shouldn't have to worry about new kevents appearing on fd 2259 * since filedesc is locked. 2260 */ 2261 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2262 KQ_LOCK(kq); 2263 2264 again: 2265 influx = 0; 2266 while (kq->kq_knlistsize > fd && 2267 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2268 if (kn->kn_status & KN_INFLUX) { 2269 /* someone else might be waiting on our knote */ 2270 if (influx) 2271 wakeup(kq); 2272 kq->kq_state |= KQ_FLUXWAIT; 2273 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2274 goto again; 2275 } 2276 kn->kn_status |= KN_INFLUX; 2277 KQ_UNLOCK(kq); 2278 if (!(kn->kn_status & KN_DETACHED)) 2279 kn->kn_fop->f_detach(kn); 2280 knote_drop(kn, td); 2281 influx = 1; 2282 KQ_LOCK(kq); 2283 } 2284 KQ_UNLOCK_FLUX(kq); 2285 } 2286 } 2287 2288 static int 2289 knote_attach(struct knote *kn, struct kqueue *kq) 2290 { 2291 struct klist *list; 2292 2293 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2294 KQ_OWNED(kq); 2295 2296 if (kn->kn_fop->f_isfd) { 2297 if (kn->kn_id >= kq->kq_knlistsize) 2298 return ENOMEM; 2299 list = &kq->kq_knlist[kn->kn_id]; 2300 } else { 2301 if (kq->kq_knhash == NULL) 2302 return ENOMEM; 2303 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2304 } 2305 2306 SLIST_INSERT_HEAD(list, kn, kn_link); 2307 2308 return 0; 2309 } 2310 2311 /* 2312 * knote must already have been detached using the f_detach method. 2313 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2314 * to prevent other removal. 2315 */ 2316 static void 2317 knote_drop(struct knote *kn, struct thread *td) 2318 { 2319 struct kqueue *kq; 2320 struct klist *list; 2321 2322 kq = kn->kn_kq; 2323 2324 KQ_NOTOWNED(kq); 2325 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2326 ("knote_drop called without KN_INFLUX set in kn_status")); 2327 2328 KQ_LOCK(kq); 2329 if (kn->kn_fop->f_isfd) 2330 list = &kq->kq_knlist[kn->kn_id]; 2331 else 2332 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2333 2334 if (!SLIST_EMPTY(list)) 2335 SLIST_REMOVE(list, kn, knote, kn_link); 2336 if (kn->kn_status & KN_QUEUED) 2337 knote_dequeue(kn); 2338 KQ_UNLOCK_FLUX(kq); 2339 2340 if (kn->kn_fop->f_isfd) { 2341 fdrop(kn->kn_fp, td); 2342 kn->kn_fp = NULL; 2343 } 2344 kqueue_fo_release(kn->kn_kevent.filter); 2345 kn->kn_fop = NULL; 2346 knote_free(kn); 2347 } 2348 2349 static void 2350 knote_enqueue(struct knote *kn) 2351 { 2352 struct kqueue *kq = kn->kn_kq; 2353 2354 KQ_OWNED(kn->kn_kq); 2355 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2356 2357 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2358 kn->kn_status |= KN_QUEUED; 2359 kq->kq_count++; 2360 kqueue_wakeup(kq); 2361 } 2362 2363 static void 2364 knote_dequeue(struct knote *kn) 2365 { 2366 struct kqueue *kq = kn->kn_kq; 2367 2368 KQ_OWNED(kn->kn_kq); 2369 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2370 2371 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2372 kn->kn_status &= ~KN_QUEUED; 2373 kq->kq_count--; 2374 } 2375 2376 static void 2377 knote_init(void) 2378 { 2379 2380 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2381 NULL, NULL, UMA_ALIGN_PTR, 0); 2382 } 2383 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2384 2385 static struct knote * 2386 knote_alloc(int waitok) 2387 { 2388 return ((struct knote *)uma_zalloc(knote_zone, 2389 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2390 } 2391 2392 static void 2393 knote_free(struct knote *kn) 2394 { 2395 if (kn != NULL) 2396 uma_zfree(knote_zone, kn); 2397 } 2398 2399 /* 2400 * Register the kev w/ the kq specified by fd. 2401 */ 2402 int 2403 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2404 { 2405 struct kqueue *kq; 2406 struct file *fp; 2407 cap_rights_t rights; 2408 int error; 2409 2410 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2411 if (error != 0) 2412 return (error); 2413 if ((error = kqueue_acquire(fp, &kq)) != 0) 2414 goto noacquire; 2415 2416 error = kqueue_register(kq, kev, td, waitok); 2417 2418 kqueue_release(kq, 0); 2419 2420 noacquire: 2421 fdrop(fp, td); 2422 2423 return error; 2424 } 2425