1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 #include <sys/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/param.h> 32 #include <sys/systm.h> 33 #include <sys/kernel.h> 34 #include <sys/lock.h> 35 #include <sys/mutex.h> 36 #include <sys/proc.h> 37 #include <sys/malloc.h> 38 #include <sys/unistd.h> 39 #include <sys/file.h> 40 #include <sys/filedesc.h> 41 #include <sys/filio.h> 42 #include <sys/fcntl.h> 43 #include <sys/kthread.h> 44 #include <sys/selinfo.h> 45 #include <sys/queue.h> 46 #include <sys/event.h> 47 #include <sys/eventvar.h> 48 #include <sys/poll.h> 49 #include <sys/protosw.h> 50 #include <sys/sigio.h> 51 #include <sys/signalvar.h> 52 #include <sys/socket.h> 53 #include <sys/socketvar.h> 54 #include <sys/stat.h> 55 #include <sys/sysctl.h> 56 #include <sys/sysproto.h> 57 #include <sys/syscallsubr.h> 58 #include <sys/taskqueue.h> 59 #include <sys/uio.h> 60 61 #include <vm/uma.h> 62 63 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 64 65 /* 66 * This lock is used if multiple kq locks are required. This possibly 67 * should be made into a per proc lock. 68 */ 69 static struct mtx kq_global; 70 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 71 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 72 if (!haslck) \ 73 mtx_lock(lck); \ 74 haslck = 1; \ 75 } while (0) 76 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 77 if (haslck) \ 78 mtx_unlock(lck); \ 79 haslck = 0; \ 80 } while (0) 81 82 TASKQUEUE_DEFINE_THREAD(kqueue); 83 84 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 85 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 86 static int kqueue_aquire(struct file *fp, struct kqueue **kqp); 87 static void kqueue_release(struct kqueue *kq, int locked); 88 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 89 uintptr_t ident, int waitok); 90 static void kqueue_task(void *arg, int pending); 91 static int kqueue_scan(struct kqueue *kq, int maxevents, 92 struct kevent_copyops *k_ops, 93 const struct timespec *timeout, 94 struct kevent *keva, struct thread *td); 95 static void kqueue_wakeup(struct kqueue *kq); 96 static struct filterops *kqueue_fo_find(int filt); 97 static void kqueue_fo_release(int filt); 98 99 static fo_rdwr_t kqueue_read; 100 static fo_rdwr_t kqueue_write; 101 static fo_ioctl_t kqueue_ioctl; 102 static fo_poll_t kqueue_poll; 103 static fo_kqfilter_t kqueue_kqfilter; 104 static fo_stat_t kqueue_stat; 105 static fo_close_t kqueue_close; 106 107 static struct fileops kqueueops = { 108 .fo_read = kqueue_read, 109 .fo_write = kqueue_write, 110 .fo_ioctl = kqueue_ioctl, 111 .fo_poll = kqueue_poll, 112 .fo_kqfilter = kqueue_kqfilter, 113 .fo_stat = kqueue_stat, 114 .fo_close = kqueue_close, 115 }; 116 117 static int knote_attach(struct knote *kn, struct kqueue *kq); 118 static void knote_drop(struct knote *kn, struct thread *td); 119 static void knote_enqueue(struct knote *kn); 120 static void knote_dequeue(struct knote *kn); 121 static void knote_init(void); 122 static struct knote *knote_alloc(int waitok); 123 static void knote_free(struct knote *kn); 124 125 static void filt_kqdetach(struct knote *kn); 126 static int filt_kqueue(struct knote *kn, long hint); 127 static int filt_procattach(struct knote *kn); 128 static void filt_procdetach(struct knote *kn); 129 static int filt_proc(struct knote *kn, long hint); 130 static int filt_fileattach(struct knote *kn); 131 static void filt_timerexpire(void *knx); 132 static int filt_timerattach(struct knote *kn); 133 static void filt_timerdetach(struct knote *kn); 134 static int filt_timer(struct knote *kn, long hint); 135 136 static struct filterops file_filtops = 137 { 1, filt_fileattach, NULL, NULL }; 138 static struct filterops kqread_filtops = 139 { 1, NULL, filt_kqdetach, filt_kqueue }; 140 /* XXX - move to kern_proc.c? */ 141 static struct filterops proc_filtops = 142 { 0, filt_procattach, filt_procdetach, filt_proc }; 143 static struct filterops timer_filtops = 144 { 0, filt_timerattach, filt_timerdetach, filt_timer }; 145 146 static uma_zone_t knote_zone; 147 static int kq_ncallouts = 0; 148 static int kq_calloutmax = (4 * 1024); 149 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 150 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 151 152 /* XXX - ensure not KN_INFLUX?? */ 153 #define KNOTE_ACTIVATE(kn, islock) do { \ 154 if ((islock)) \ 155 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 156 else \ 157 KQ_LOCK((kn)->kn_kq); \ 158 (kn)->kn_status |= KN_ACTIVE; \ 159 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 160 knote_enqueue((kn)); \ 161 if (!(islock)) \ 162 KQ_UNLOCK((kn)->kn_kq); \ 163 } while(0) 164 #define KQ_LOCK(kq) do { \ 165 mtx_lock(&(kq)->kq_lock); \ 166 } while (0) 167 #define KQ_FLUX_WAKEUP(kq) do { \ 168 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 169 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 170 wakeup((kq)); \ 171 } \ 172 } while (0) 173 #define KQ_UNLOCK_FLUX(kq) do { \ 174 KQ_FLUX_WAKEUP(kq); \ 175 mtx_unlock(&(kq)->kq_lock); \ 176 } while (0) 177 #define KQ_UNLOCK(kq) do { \ 178 mtx_unlock(&(kq)->kq_lock); \ 179 } while (0) 180 #define KQ_OWNED(kq) do { \ 181 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 182 } while (0) 183 #define KQ_NOTOWNED(kq) do { \ 184 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 185 } while (0) 186 #define KN_LIST_LOCK(kn) do { \ 187 if (kn->kn_knlist != NULL) \ 188 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 189 } while (0) 190 #define KN_LIST_UNLOCK(kn) do { \ 191 if (kn->kn_knlist != NULL) \ 192 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 193 } while (0) 194 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 195 if (islocked) \ 196 KNL_ASSERT_LOCKED(knl); \ 197 else \ 198 KNL_ASSERT_UNLOCKED(knl); \ 199 } while (0) 200 #ifdef INVARIANTS 201 #define KNL_ASSERT_LOCKED(knl) do { \ 202 if (!knl->kl_locked((knl)->kl_lockarg)) \ 203 panic("knlist not locked, but should be"); \ 204 } while (0) 205 #define KNL_ASSERT_UNLOCKED(knl) do { \ 206 if (knl->kl_locked((knl)->kl_lockarg)) \ 207 panic("knlist locked, but should not be"); \ 208 } while (0) 209 #else /* !INVARIANTS */ 210 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 211 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 212 #endif /* INVARIANTS */ 213 214 #define KN_HASHSIZE 64 /* XXX should be tunable */ 215 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 216 217 static int 218 filt_nullattach(struct knote *kn) 219 { 220 221 return (ENXIO); 222 }; 223 224 struct filterops null_filtops = 225 { 0, filt_nullattach, NULL, NULL }; 226 227 /* XXX - make SYSINIT to add these, and move into respective modules. */ 228 extern struct filterops sig_filtops; 229 extern struct filterops fs_filtops; 230 231 /* 232 * Table for for all system-defined filters. 233 */ 234 static struct mtx filterops_lock; 235 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 236 MTX_DEF); 237 static struct { 238 struct filterops *for_fop; 239 int for_refcnt; 240 } sysfilt_ops[EVFILT_SYSCOUNT] = { 241 { &file_filtops }, /* EVFILT_READ */ 242 { &file_filtops }, /* EVFILT_WRITE */ 243 { &null_filtops }, /* EVFILT_AIO */ 244 { &file_filtops }, /* EVFILT_VNODE */ 245 { &proc_filtops }, /* EVFILT_PROC */ 246 { &sig_filtops }, /* EVFILT_SIGNAL */ 247 { &timer_filtops }, /* EVFILT_TIMER */ 248 { &file_filtops }, /* EVFILT_NETDEV */ 249 { &fs_filtops }, /* EVFILT_FS */ 250 { &null_filtops }, /* EVFILT_LIO */ 251 }; 252 253 /* 254 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 255 * method. 256 */ 257 static int 258 filt_fileattach(struct knote *kn) 259 { 260 261 return (fo_kqfilter(kn->kn_fp, kn)); 262 } 263 264 /*ARGSUSED*/ 265 static int 266 kqueue_kqfilter(struct file *fp, struct knote *kn) 267 { 268 struct kqueue *kq = kn->kn_fp->f_data; 269 270 if (kn->kn_filter != EVFILT_READ) 271 return (EINVAL); 272 273 kn->kn_status |= KN_KQUEUE; 274 kn->kn_fop = &kqread_filtops; 275 knlist_add(&kq->kq_sel.si_note, kn, 0); 276 277 return (0); 278 } 279 280 static void 281 filt_kqdetach(struct knote *kn) 282 { 283 struct kqueue *kq = kn->kn_fp->f_data; 284 285 knlist_remove(&kq->kq_sel.si_note, kn, 0); 286 } 287 288 /*ARGSUSED*/ 289 static int 290 filt_kqueue(struct knote *kn, long hint) 291 { 292 struct kqueue *kq = kn->kn_fp->f_data; 293 294 kn->kn_data = kq->kq_count; 295 return (kn->kn_data > 0); 296 } 297 298 /* XXX - move to kern_proc.c? */ 299 static int 300 filt_procattach(struct knote *kn) 301 { 302 struct proc *p; 303 int immediate; 304 int error; 305 306 immediate = 0; 307 p = pfind(kn->kn_id); 308 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 309 p = zpfind(kn->kn_id); 310 immediate = 1; 311 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 312 immediate = 1; 313 } 314 315 if (p == NULL) 316 return (ESRCH); 317 if ((error = p_cansee(curthread, p))) 318 return (error); 319 320 kn->kn_ptr.p_proc = p; 321 kn->kn_flags |= EV_CLEAR; /* automatically set */ 322 323 /* 324 * internal flag indicating registration done by kernel 325 */ 326 if (kn->kn_flags & EV_FLAG1) { 327 kn->kn_data = kn->kn_sdata; /* ppid */ 328 kn->kn_fflags = NOTE_CHILD; 329 kn->kn_flags &= ~EV_FLAG1; 330 } 331 332 if (immediate == 0) 333 knlist_add(&p->p_klist, kn, 1); 334 335 /* 336 * Immediately activate any exit notes if the target process is a 337 * zombie. This is necessary to handle the case where the target 338 * process, e.g. a child, dies before the kevent is registered. 339 */ 340 if (immediate && filt_proc(kn, NOTE_EXIT)) 341 KNOTE_ACTIVATE(kn, 0); 342 343 PROC_UNLOCK(p); 344 345 return (0); 346 } 347 348 /* 349 * The knote may be attached to a different process, which may exit, 350 * leaving nothing for the knote to be attached to. So when the process 351 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 352 * it will be deleted when read out. However, as part of the knote deletion, 353 * this routine is called, so a check is needed to avoid actually performing 354 * a detach, because the original process does not exist any more. 355 */ 356 /* XXX - move to kern_proc.c? */ 357 static void 358 filt_procdetach(struct knote *kn) 359 { 360 struct proc *p; 361 362 p = kn->kn_ptr.p_proc; 363 knlist_remove(&p->p_klist, kn, 0); 364 kn->kn_ptr.p_proc = NULL; 365 } 366 367 /* XXX - move to kern_proc.c? */ 368 static int 369 filt_proc(struct knote *kn, long hint) 370 { 371 struct proc *p = kn->kn_ptr.p_proc; 372 u_int event; 373 374 /* 375 * mask off extra data 376 */ 377 event = (u_int)hint & NOTE_PCTRLMASK; 378 379 /* 380 * if the user is interested in this event, record it. 381 */ 382 if (kn->kn_sfflags & event) 383 kn->kn_fflags |= event; 384 385 /* 386 * process is gone, so flag the event as finished. 387 */ 388 if (event == NOTE_EXIT) { 389 if (!(kn->kn_status & KN_DETACHED)) 390 knlist_remove_inevent(&p->p_klist, kn); 391 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 392 kn->kn_ptr.p_proc = NULL; 393 return (1); 394 } 395 396 /* 397 * process forked, and user wants to track the new process, 398 * so attach a new knote to it, and immediately report an 399 * event with the parent's pid. 400 */ 401 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 402 struct kevent kev; 403 int error; 404 405 /* 406 * register knote with new process. 407 */ 408 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 409 kev.filter = kn->kn_filter; 410 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 411 kev.fflags = kn->kn_sfflags; 412 kev.data = kn->kn_id; /* parent */ 413 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 414 error = kqueue_register(kn->kn_kq, &kev, NULL, 0); 415 if (error) 416 kn->kn_fflags |= NOTE_TRACKERR; 417 } 418 419 return (kn->kn_fflags != 0); 420 } 421 422 static int 423 timertoticks(intptr_t data) 424 { 425 struct timeval tv; 426 int tticks; 427 428 tv.tv_sec = data / 1000; 429 tv.tv_usec = (data % 1000) * 1000; 430 tticks = tvtohz(&tv); 431 432 return tticks; 433 } 434 435 /* XXX - move to kern_timeout.c? */ 436 static void 437 filt_timerexpire(void *knx) 438 { 439 struct knote *kn = knx; 440 struct callout *calloutp; 441 442 kn->kn_data++; 443 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 444 445 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 446 calloutp = (struct callout *)kn->kn_hook; 447 callout_reset(calloutp, timertoticks(kn->kn_sdata), 448 filt_timerexpire, kn); 449 } 450 } 451 452 /* 453 * data contains amount of time to sleep, in milliseconds 454 */ 455 /* XXX - move to kern_timeout.c? */ 456 static int 457 filt_timerattach(struct knote *kn) 458 { 459 struct callout *calloutp; 460 461 atomic_add_int(&kq_ncallouts, 1); 462 463 if (kq_ncallouts >= kq_calloutmax) { 464 atomic_add_int(&kq_ncallouts, -1); 465 return (ENOMEM); 466 } 467 468 kn->kn_flags |= EV_CLEAR; /* automatically set */ 469 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */ 470 MALLOC(calloutp, struct callout *, sizeof(*calloutp), 471 M_KQUEUE, M_WAITOK); 472 callout_init(calloutp, CALLOUT_MPSAFE); 473 kn->kn_hook = calloutp; 474 callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire, 475 kn); 476 477 return (0); 478 } 479 480 /* XXX - move to kern_timeout.c? */ 481 static void 482 filt_timerdetach(struct knote *kn) 483 { 484 struct callout *calloutp; 485 486 calloutp = (struct callout *)kn->kn_hook; 487 callout_drain(calloutp); 488 FREE(calloutp, M_KQUEUE); 489 atomic_add_int(&kq_ncallouts, -1); 490 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */ 491 } 492 493 /* XXX - move to kern_timeout.c? */ 494 static int 495 filt_timer(struct knote *kn, long hint) 496 { 497 498 return (kn->kn_data != 0); 499 } 500 501 /* 502 * MPSAFE 503 */ 504 int 505 kqueue(struct thread *td, struct kqueue_args *uap) 506 { 507 struct filedesc *fdp; 508 struct kqueue *kq; 509 struct file *fp; 510 int fd, error; 511 512 fdp = td->td_proc->p_fd; 513 error = falloc(td, &fp, &fd); 514 if (error) 515 goto done2; 516 517 /* An extra reference on `nfp' has been held for us by falloc(). */ 518 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 519 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 520 TAILQ_INIT(&kq->kq_head); 521 kq->kq_fdp = fdp; 522 knlist_init(&kq->kq_sel.si_note, &kq->kq_lock, NULL, NULL, NULL); 523 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 524 525 FILEDESC_LOCK_FAST(fdp); 526 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 527 FILEDESC_UNLOCK_FAST(fdp); 528 529 FILE_LOCK(fp); 530 fp->f_flag = FREAD | FWRITE; 531 fp->f_type = DTYPE_KQUEUE; 532 fp->f_ops = &kqueueops; 533 fp->f_data = kq; 534 FILE_UNLOCK(fp); 535 fdrop(fp, td); 536 537 td->td_retval[0] = fd; 538 done2: 539 return (error); 540 } 541 542 #ifndef _SYS_SYSPROTO_H_ 543 struct kevent_args { 544 int fd; 545 const struct kevent *changelist; 546 int nchanges; 547 struct kevent *eventlist; 548 int nevents; 549 const struct timespec *timeout; 550 }; 551 #endif 552 /* 553 * MPSAFE 554 */ 555 int 556 kevent(struct thread *td, struct kevent_args *uap) 557 { 558 struct timespec ts, *tsp; 559 struct kevent_copyops k_ops = { uap, 560 kevent_copyout, 561 kevent_copyin}; 562 int error; 563 564 if (uap->timeout != NULL) { 565 error = copyin(uap->timeout, &ts, sizeof(ts)); 566 if (error) 567 return (error); 568 tsp = &ts; 569 } else 570 tsp = NULL; 571 572 return (kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 573 &k_ops, tsp)); 574 } 575 576 /* 577 * Copy 'count' items into the destination list pointed to by uap->eventlist. 578 */ 579 static int 580 kevent_copyout(void *arg, struct kevent *kevp, int count) 581 { 582 struct kevent_args *uap; 583 int error; 584 585 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 586 uap = (struct kevent_args *)arg; 587 588 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 589 if (error == 0) 590 uap->eventlist += count; 591 return (error); 592 } 593 594 /* 595 * Copy 'count' items from the list pointed to by uap->changelist. 596 */ 597 static int 598 kevent_copyin(void *arg, struct kevent *kevp, int count) 599 { 600 struct kevent_args *uap; 601 int error; 602 603 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 604 uap = (struct kevent_args *)arg; 605 606 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 607 if (error == 0) 608 uap->changelist += count; 609 return (error); 610 } 611 612 int 613 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 614 struct kevent_copyops *k_ops, const struct timespec *timeout) 615 { 616 struct kevent keva[KQ_NEVENTS]; 617 struct kevent *kevp, *changes; 618 struct kqueue *kq; 619 struct file *fp; 620 int i, n, nerrors, error; 621 622 if ((error = fget(td, fd, &fp)) != 0) 623 return (error); 624 if ((error = kqueue_aquire(fp, &kq)) != 0) 625 goto done_norel; 626 627 nerrors = 0; 628 629 while (nchanges > 0) { 630 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 631 error = k_ops->k_copyin(k_ops->arg, keva, n); 632 if (error) 633 goto done; 634 changes = keva; 635 for (i = 0; i < n; i++) { 636 kevp = &changes[i]; 637 if (!kevp->filter) 638 continue; 639 kevp->flags &= ~EV_SYSFLAGS; 640 error = kqueue_register(kq, kevp, td, 1); 641 if (error) { 642 if (nevents != 0) { 643 kevp->flags = EV_ERROR; 644 kevp->data = error; 645 (void) k_ops->k_copyout(k_ops->arg, 646 kevp, 1); 647 nevents--; 648 nerrors++; 649 } else { 650 goto done; 651 } 652 } 653 } 654 nchanges -= n; 655 } 656 if (nerrors) { 657 td->td_retval[0] = nerrors; 658 error = 0; 659 goto done; 660 } 661 662 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 663 done: 664 kqueue_release(kq, 0); 665 done_norel: 666 if (fp != NULL) 667 fdrop(fp, td); 668 return (error); 669 } 670 671 int 672 kqueue_add_filteropts(int filt, struct filterops *filtops) 673 { 674 int error; 675 676 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 677 printf( 678 "trying to add a filterop that is out of range: %d is beyond %d\n", 679 ~filt, EVFILT_SYSCOUNT); 680 return EINVAL; 681 } 682 mtx_lock(&filterops_lock); 683 if (sysfilt_ops[~filt].for_fop != &null_filtops && 684 sysfilt_ops[~filt].for_fop != NULL) 685 error = EEXIST; 686 else { 687 sysfilt_ops[~filt].for_fop = filtops; 688 sysfilt_ops[~filt].for_refcnt = 0; 689 } 690 mtx_unlock(&filterops_lock); 691 692 return (0); 693 } 694 695 int 696 kqueue_del_filteropts(int filt) 697 { 698 int error; 699 700 error = 0; 701 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 702 return EINVAL; 703 704 mtx_lock(&filterops_lock); 705 if (sysfilt_ops[~filt].for_fop == &null_filtops || 706 sysfilt_ops[~filt].for_fop == NULL) 707 error = EINVAL; 708 else if (sysfilt_ops[~filt].for_refcnt != 0) 709 error = EBUSY; 710 else { 711 sysfilt_ops[~filt].for_fop = &null_filtops; 712 sysfilt_ops[~filt].for_refcnt = 0; 713 } 714 mtx_unlock(&filterops_lock); 715 716 return error; 717 } 718 719 static struct filterops * 720 kqueue_fo_find(int filt) 721 { 722 723 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 724 return NULL; 725 726 mtx_lock(&filterops_lock); 727 sysfilt_ops[~filt].for_refcnt++; 728 if (sysfilt_ops[~filt].for_fop == NULL) 729 sysfilt_ops[~filt].for_fop = &null_filtops; 730 mtx_unlock(&filterops_lock); 731 732 return sysfilt_ops[~filt].for_fop; 733 } 734 735 static void 736 kqueue_fo_release(int filt) 737 { 738 739 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 740 return; 741 742 mtx_lock(&filterops_lock); 743 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 744 ("filter object refcount not valid on release")); 745 sysfilt_ops[~filt].for_refcnt--; 746 mtx_unlock(&filterops_lock); 747 } 748 749 /* 750 * A ref to kq (obtained via kqueue_aquire) should be held. waitok will 751 * influence if memory allocation should wait. Make sure it is 0 if you 752 * hold any mutexes. 753 */ 754 int 755 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 756 { 757 struct filterops *fops; 758 struct file *fp; 759 struct knote *kn, *tkn; 760 int error, filt, event; 761 int haskqglobal; 762 763 fp = NULL; 764 kn = NULL; 765 error = 0; 766 haskqglobal = 0; 767 768 filt = kev->filter; 769 fops = kqueue_fo_find(filt); 770 if (fops == NULL) 771 return EINVAL; 772 773 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 774 775 findkn: 776 if (fops->f_isfd) { 777 KASSERT(td != NULL, ("td is NULL")); 778 error = fget(td, kev->ident, &fp); 779 if (error) 780 goto done; 781 782 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 783 kev->ident, 0) != 0) { 784 /* try again */ 785 fdrop(fp, td); 786 fp = NULL; 787 error = kqueue_expand(kq, fops, kev->ident, waitok); 788 if (error) 789 goto done; 790 goto findkn; 791 } 792 793 if (fp->f_type == DTYPE_KQUEUE) { 794 /* 795 * if we add some inteligence about what we are doing, 796 * we should be able to support events on ourselves. 797 * We need to know when we are doing this to prevent 798 * getting both the knlist lock and the kq lock since 799 * they are the same thing. 800 */ 801 if (fp->f_data == kq) { 802 error = EINVAL; 803 goto done; 804 } 805 806 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 807 } 808 809 KQ_LOCK(kq); 810 if (kev->ident < kq->kq_knlistsize) { 811 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 812 if (kev->filter == kn->kn_filter) 813 break; 814 } 815 } else { 816 if ((kev->flags & EV_ADD) == EV_ADD) 817 kqueue_expand(kq, fops, kev->ident, waitok); 818 819 KQ_LOCK(kq); 820 if (kq->kq_knhashmask != 0) { 821 struct klist *list; 822 823 list = &kq->kq_knhash[ 824 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 825 SLIST_FOREACH(kn, list, kn_link) 826 if (kev->ident == kn->kn_id && 827 kev->filter == kn->kn_filter) 828 break; 829 } 830 } 831 832 /* knote is in the process of changing, wait for it to stablize. */ 833 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 834 if (fp != NULL) { 835 fdrop(fp, td); 836 fp = NULL; 837 } 838 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 839 kq->kq_state |= KQ_FLUXWAIT; 840 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 841 goto findkn; 842 } 843 844 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { 845 KQ_UNLOCK(kq); 846 error = ENOENT; 847 goto done; 848 } 849 850 /* 851 * kn now contains the matching knote, or NULL if no match 852 */ 853 if (kev->flags & EV_ADD) { 854 if (kn == NULL) { 855 kn = tkn; 856 tkn = NULL; 857 if (kn == NULL) { 858 KQ_UNLOCK(kq); 859 error = ENOMEM; 860 goto done; 861 } 862 kn->kn_fp = fp; 863 kn->kn_kq = kq; 864 kn->kn_fop = fops; 865 /* 866 * apply reference counts to knote structure, and 867 * do not release it at the end of this routine. 868 */ 869 fops = NULL; 870 fp = NULL; 871 872 kn->kn_sfflags = kev->fflags; 873 kn->kn_sdata = kev->data; 874 kev->fflags = 0; 875 kev->data = 0; 876 kn->kn_kevent = *kev; 877 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 878 EV_ENABLE | EV_DISABLE); 879 kn->kn_status = KN_INFLUX|KN_DETACHED; 880 881 error = knote_attach(kn, kq); 882 KQ_UNLOCK(kq); 883 if (error != 0) { 884 tkn = kn; 885 goto done; 886 } 887 888 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 889 knote_drop(kn, td); 890 goto done; 891 } 892 KN_LIST_LOCK(kn); 893 } else { 894 /* 895 * The user may change some filter values after the 896 * initial EV_ADD, but doing so will not reset any 897 * filter which has already been triggered. 898 */ 899 kn->kn_status |= KN_INFLUX; 900 KQ_UNLOCK(kq); 901 KN_LIST_LOCK(kn); 902 kn->kn_sfflags = kev->fflags; 903 kn->kn_sdata = kev->data; 904 kn->kn_kevent.udata = kev->udata; 905 } 906 907 /* 908 * We can get here with kn->kn_knlist == NULL. 909 * This can happen when the initial attach event decides that 910 * the event is "completed" already. i.e. filt_procattach 911 * is called on a zombie process. It will call filt_proc 912 * which will remove it from the list, and NULL kn_knlist. 913 */ 914 event = kn->kn_fop->f_event(kn, 0); 915 KQ_LOCK(kq); 916 if (event) 917 KNOTE_ACTIVATE(kn, 1); 918 kn->kn_status &= ~KN_INFLUX; 919 KN_LIST_UNLOCK(kn); 920 } else if (kev->flags & EV_DELETE) { 921 kn->kn_status |= KN_INFLUX; 922 KQ_UNLOCK(kq); 923 if (!(kn->kn_status & KN_DETACHED)) 924 kn->kn_fop->f_detach(kn); 925 knote_drop(kn, td); 926 goto done; 927 } 928 929 if ((kev->flags & EV_DISABLE) && 930 ((kn->kn_status & KN_DISABLED) == 0)) { 931 kn->kn_status |= KN_DISABLED; 932 } 933 934 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 935 kn->kn_status &= ~KN_DISABLED; 936 if ((kn->kn_status & KN_ACTIVE) && 937 ((kn->kn_status & KN_QUEUED) == 0)) 938 knote_enqueue(kn); 939 } 940 KQ_UNLOCK_FLUX(kq); 941 942 done: 943 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 944 if (fp != NULL) 945 fdrop(fp, td); 946 if (tkn != NULL) 947 knote_free(tkn); 948 if (fops != NULL) 949 kqueue_fo_release(filt); 950 return (error); 951 } 952 953 static int 954 kqueue_aquire(struct file *fp, struct kqueue **kqp) 955 { 956 int error; 957 struct kqueue *kq; 958 959 error = 0; 960 961 FILE_LOCK(fp); 962 do { 963 kq = fp->f_data; 964 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) { 965 error = EBADF; 966 break; 967 } 968 *kqp = kq; 969 KQ_LOCK(kq); 970 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 971 KQ_UNLOCK(kq); 972 error = EBADF; 973 break; 974 } 975 kq->kq_refcnt++; 976 KQ_UNLOCK(kq); 977 } while (0); 978 FILE_UNLOCK(fp); 979 980 return error; 981 } 982 983 static void 984 kqueue_release(struct kqueue *kq, int locked) 985 { 986 if (locked) 987 KQ_OWNED(kq); 988 else 989 KQ_LOCK(kq); 990 kq->kq_refcnt--; 991 if (kq->kq_refcnt == 1) 992 wakeup(&kq->kq_refcnt); 993 if (!locked) 994 KQ_UNLOCK(kq); 995 } 996 997 static void 998 kqueue_schedtask(struct kqueue *kq) 999 { 1000 1001 KQ_OWNED(kq); 1002 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1003 ("scheduling kqueue task while draining")); 1004 1005 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1006 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1007 kq->kq_state |= KQ_TASKSCHED; 1008 } 1009 } 1010 1011 /* 1012 * Expand the kq to make sure we have storage for fops/ident pair. 1013 * 1014 * Return 0 on success (or no work necessary), return errno on failure. 1015 * 1016 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1017 * If kqueue_register is called from a non-fd context, there usually/should 1018 * be no locks held. 1019 */ 1020 static int 1021 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1022 int waitok) 1023 { 1024 struct klist *list, *tmp_knhash; 1025 u_long tmp_knhashmask; 1026 int size; 1027 int fd; 1028 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1029 1030 KQ_NOTOWNED(kq); 1031 1032 if (fops->f_isfd) { 1033 fd = ident; 1034 if (kq->kq_knlistsize <= fd) { 1035 size = kq->kq_knlistsize; 1036 while (size <= fd) 1037 size += KQEXTENT; 1038 MALLOC(list, struct klist *, 1039 size * sizeof list, M_KQUEUE, mflag); 1040 if (list == NULL) 1041 return ENOMEM; 1042 KQ_LOCK(kq); 1043 if (kq->kq_knlistsize > fd) { 1044 FREE(list, M_KQUEUE); 1045 list = NULL; 1046 } else { 1047 if (kq->kq_knlist != NULL) { 1048 bcopy(kq->kq_knlist, list, 1049 kq->kq_knlistsize * sizeof list); 1050 FREE(kq->kq_knlist, M_KQUEUE); 1051 kq->kq_knlist = NULL; 1052 } 1053 bzero((caddr_t)list + 1054 kq->kq_knlistsize * sizeof list, 1055 (size - kq->kq_knlistsize) * sizeof list); 1056 kq->kq_knlistsize = size; 1057 kq->kq_knlist = list; 1058 } 1059 KQ_UNLOCK(kq); 1060 } 1061 } else { 1062 if (kq->kq_knhashmask == 0) { 1063 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1064 &tmp_knhashmask); 1065 if (tmp_knhash == NULL) 1066 return ENOMEM; 1067 KQ_LOCK(kq); 1068 if (kq->kq_knhashmask == 0) { 1069 kq->kq_knhash = tmp_knhash; 1070 kq->kq_knhashmask = tmp_knhashmask; 1071 } else { 1072 free(tmp_knhash, M_KQUEUE); 1073 } 1074 KQ_UNLOCK(kq); 1075 } 1076 } 1077 1078 KQ_NOTOWNED(kq); 1079 return 0; 1080 } 1081 1082 static void 1083 kqueue_task(void *arg, int pending) 1084 { 1085 struct kqueue *kq; 1086 int haskqglobal; 1087 1088 haskqglobal = 0; 1089 kq = arg; 1090 1091 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1092 KQ_LOCK(kq); 1093 1094 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1095 1096 kq->kq_state &= ~KQ_TASKSCHED; 1097 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1098 wakeup(&kq->kq_state); 1099 } 1100 KQ_UNLOCK(kq); 1101 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1102 } 1103 1104 /* 1105 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1106 * We treat KN_MARKER knotes as if they are INFLUX. 1107 */ 1108 static int 1109 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1110 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1111 { 1112 struct kevent *kevp; 1113 struct timeval atv, rtv, ttv; 1114 struct knote *kn, *marker; 1115 int count, timeout, nkev, error; 1116 int haskqglobal; 1117 1118 count = maxevents; 1119 nkev = 0; 1120 error = 0; 1121 haskqglobal = 0; 1122 1123 if (maxevents == 0) 1124 goto done_nl; 1125 1126 if (tsp != NULL) { 1127 TIMESPEC_TO_TIMEVAL(&atv, tsp); 1128 if (itimerfix(&atv)) { 1129 error = EINVAL; 1130 goto done_nl; 1131 } 1132 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 1133 timeout = -1; 1134 else 1135 timeout = atv.tv_sec > 24 * 60 * 60 ? 1136 24 * 60 * 60 * hz : tvtohz(&atv); 1137 getmicrouptime(&rtv); 1138 timevaladd(&atv, &rtv); 1139 } else { 1140 atv.tv_sec = 0; 1141 atv.tv_usec = 0; 1142 timeout = 0; 1143 } 1144 marker = knote_alloc(1); 1145 if (marker == NULL) { 1146 error = ENOMEM; 1147 goto done_nl; 1148 } 1149 marker->kn_status = KN_MARKER; 1150 KQ_LOCK(kq); 1151 goto start; 1152 1153 retry: 1154 if (atv.tv_sec || atv.tv_usec) { 1155 getmicrouptime(&rtv); 1156 if (timevalcmp(&rtv, &atv, >=)) 1157 goto done; 1158 ttv = atv; 1159 timevalsub(&ttv, &rtv); 1160 timeout = ttv.tv_sec > 24 * 60 * 60 ? 1161 24 * 60 * 60 * hz : tvtohz(&ttv); 1162 } 1163 1164 start: 1165 kevp = keva; 1166 if (kq->kq_count == 0) { 1167 if (timeout < 0) { 1168 error = EWOULDBLOCK; 1169 } else { 1170 kq->kq_state |= KQ_SLEEP; 1171 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, 1172 "kqread", timeout); 1173 } 1174 if (error == 0) 1175 goto retry; 1176 /* don't restart after signals... */ 1177 if (error == ERESTART) 1178 error = EINTR; 1179 else if (error == EWOULDBLOCK) 1180 error = 0; 1181 goto done; 1182 } 1183 1184 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1185 while (count) { 1186 KQ_OWNED(kq); 1187 kn = TAILQ_FIRST(&kq->kq_head); 1188 1189 if ((kn->kn_status == KN_MARKER && kn != marker) || 1190 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1191 kq->kq_state |= KQ_FLUXWAIT; 1192 error = msleep(kq, &kq->kq_lock, PSOCK, 1193 "kqflxwt", 0); 1194 continue; 1195 } 1196 1197 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1198 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1199 kn->kn_status &= ~KN_QUEUED; 1200 kq->kq_count--; 1201 continue; 1202 } 1203 if (kn == marker) { 1204 KQ_FLUX_WAKEUP(kq); 1205 if (count == maxevents) 1206 goto retry; 1207 goto done; 1208 } 1209 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1210 ("KN_INFLUX set when not suppose to be")); 1211 1212 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1213 kn->kn_status &= ~KN_QUEUED; 1214 kn->kn_status |= KN_INFLUX; 1215 kq->kq_count--; 1216 KQ_UNLOCK(kq); 1217 /* 1218 * We don't need to lock the list since we've marked 1219 * it _INFLUX. 1220 */ 1221 *kevp = kn->kn_kevent; 1222 if (!(kn->kn_status & KN_DETACHED)) 1223 kn->kn_fop->f_detach(kn); 1224 knote_drop(kn, td); 1225 KQ_LOCK(kq); 1226 kn = NULL; 1227 } else { 1228 kn->kn_status |= KN_INFLUX; 1229 KQ_UNLOCK(kq); 1230 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1231 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1232 KN_LIST_LOCK(kn); 1233 if (kn->kn_fop->f_event(kn, 0) == 0) { 1234 KQ_LOCK(kq); 1235 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1236 kn->kn_status &= 1237 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1238 kq->kq_count--; 1239 KN_LIST_UNLOCK(kn); 1240 continue; 1241 } 1242 *kevp = kn->kn_kevent; 1243 KQ_LOCK(kq); 1244 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1245 if (kn->kn_flags & EV_CLEAR) { 1246 kn->kn_data = 0; 1247 kn->kn_fflags = 0; 1248 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1249 kq->kq_count--; 1250 } else 1251 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1252 1253 kn->kn_status &= ~(KN_INFLUX); 1254 KN_LIST_UNLOCK(kn); 1255 } 1256 1257 /* we are returning a copy to the user */ 1258 kevp++; 1259 nkev++; 1260 count--; 1261 1262 if (nkev == KQ_NEVENTS) { 1263 KQ_UNLOCK_FLUX(kq); 1264 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1265 nkev = 0; 1266 kevp = keva; 1267 KQ_LOCK(kq); 1268 if (error) 1269 break; 1270 } 1271 } 1272 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1273 done: 1274 KQ_OWNED(kq); 1275 KQ_UNLOCK_FLUX(kq); 1276 knote_free(marker); 1277 done_nl: 1278 KQ_NOTOWNED(kq); 1279 if (nkev != 0) 1280 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1281 td->td_retval[0] = maxevents - count; 1282 return (error); 1283 } 1284 1285 /* 1286 * XXX 1287 * This could be expanded to call kqueue_scan, if desired. 1288 */ 1289 /*ARGSUSED*/ 1290 static int 1291 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1292 int flags, struct thread *td) 1293 { 1294 return (ENXIO); 1295 } 1296 1297 /*ARGSUSED*/ 1298 static int 1299 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1300 int flags, struct thread *td) 1301 { 1302 return (ENXIO); 1303 } 1304 1305 /*ARGSUSED*/ 1306 static int 1307 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1308 struct ucred *active_cred, struct thread *td) 1309 { 1310 /* 1311 * Enabling sigio causes two major problems: 1312 * 1) infinite recursion: 1313 * Synopsys: kevent is being used to track signals and have FIOASYNC 1314 * set. On receipt of a signal this will cause a kqueue to recurse 1315 * into itself over and over. Sending the sigio causes the kqueue 1316 * to become ready, which in turn posts sigio again, forever. 1317 * Solution: this can be solved by setting a flag in the kqueue that 1318 * we have a SIGIO in progress. 1319 * 2) locking problems: 1320 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1321 * us above the proc and pgrp locks. 1322 * Solution: Post a signal using an async mechanism, being sure to 1323 * record a generation count in the delivery so that we do not deliver 1324 * a signal to the wrong process. 1325 * 1326 * Note, these two mechanisms are somewhat mutually exclusive! 1327 */ 1328 #if 0 1329 struct kqueue *kq; 1330 1331 kq = fp->f_data; 1332 switch (cmd) { 1333 case FIOASYNC: 1334 if (*(int *)data) { 1335 kq->kq_state |= KQ_ASYNC; 1336 } else { 1337 kq->kq_state &= ~KQ_ASYNC; 1338 } 1339 return (0); 1340 1341 case FIOSETOWN: 1342 return (fsetown(*(int *)data, &kq->kq_sigio)); 1343 1344 case FIOGETOWN: 1345 *(int *)data = fgetown(&kq->kq_sigio); 1346 return (0); 1347 } 1348 #endif 1349 1350 return (ENOTTY); 1351 } 1352 1353 /*ARGSUSED*/ 1354 static int 1355 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1356 struct thread *td) 1357 { 1358 struct kqueue *kq; 1359 int revents = 0; 1360 int error; 1361 1362 if ((error = kqueue_aquire(fp, &kq))) 1363 return POLLERR; 1364 1365 KQ_LOCK(kq); 1366 if (events & (POLLIN | POLLRDNORM)) { 1367 if (kq->kq_count) { 1368 revents |= events & (POLLIN | POLLRDNORM); 1369 } else { 1370 selrecord(td, &kq->kq_sel); 1371 kq->kq_state |= KQ_SEL; 1372 } 1373 } 1374 kqueue_release(kq, 1); 1375 KQ_UNLOCK(kq); 1376 return (revents); 1377 } 1378 1379 /*ARGSUSED*/ 1380 static int 1381 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1382 struct thread *td) 1383 { 1384 1385 bzero((void *)st, sizeof *st); 1386 /* 1387 * We no longer return kq_count because the unlocked value is useless. 1388 * If you spent all this time getting the count, why not spend your 1389 * syscall better by calling kevent? 1390 * 1391 * XXX - This is needed for libc_r. 1392 */ 1393 st->st_mode = S_IFIFO; 1394 return (0); 1395 } 1396 1397 /*ARGSUSED*/ 1398 static int 1399 kqueue_close(struct file *fp, struct thread *td) 1400 { 1401 struct kqueue *kq = fp->f_data; 1402 struct filedesc *fdp; 1403 struct knote *kn; 1404 int i; 1405 int error; 1406 1407 if ((error = kqueue_aquire(fp, &kq))) 1408 return error; 1409 1410 KQ_LOCK(kq); 1411 1412 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1413 ("kqueue already closing")); 1414 kq->kq_state |= KQ_CLOSING; 1415 if (kq->kq_refcnt > 1) 1416 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1417 1418 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1419 fdp = kq->kq_fdp; 1420 1421 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1422 ("kqueue's knlist not empty")); 1423 1424 for (i = 0; i < kq->kq_knlistsize; i++) { 1425 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1426 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1427 ("KN_INFLUX set when not suppose to be")); 1428 kn->kn_status |= KN_INFLUX; 1429 KQ_UNLOCK(kq); 1430 if (!(kn->kn_status & KN_DETACHED)) 1431 kn->kn_fop->f_detach(kn); 1432 knote_drop(kn, td); 1433 KQ_LOCK(kq); 1434 } 1435 } 1436 if (kq->kq_knhashmask != 0) { 1437 for (i = 0; i <= kq->kq_knhashmask; i++) { 1438 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1439 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1440 ("KN_INFLUX set when not suppose to be")); 1441 kn->kn_status |= KN_INFLUX; 1442 KQ_UNLOCK(kq); 1443 if (!(kn->kn_status & KN_DETACHED)) 1444 kn->kn_fop->f_detach(kn); 1445 knote_drop(kn, td); 1446 KQ_LOCK(kq); 1447 } 1448 } 1449 } 1450 1451 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1452 kq->kq_state |= KQ_TASKDRAIN; 1453 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1454 } 1455 1456 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1457 kq->kq_state &= ~KQ_SEL; 1458 selwakeuppri(&kq->kq_sel, PSOCK); 1459 } 1460 1461 KQ_UNLOCK(kq); 1462 1463 FILEDESC_LOCK_FAST(fdp); 1464 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); 1465 FILEDESC_UNLOCK_FAST(fdp); 1466 1467 knlist_destroy(&kq->kq_sel.si_note); 1468 mtx_destroy(&kq->kq_lock); 1469 kq->kq_fdp = NULL; 1470 1471 if (kq->kq_knhash != NULL) 1472 free(kq->kq_knhash, M_KQUEUE); 1473 if (kq->kq_knlist != NULL) 1474 free(kq->kq_knlist, M_KQUEUE); 1475 1476 funsetown(&kq->kq_sigio); 1477 free(kq, M_KQUEUE); 1478 fp->f_data = NULL; 1479 1480 return (0); 1481 } 1482 1483 static void 1484 kqueue_wakeup(struct kqueue *kq) 1485 { 1486 KQ_OWNED(kq); 1487 1488 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1489 kq->kq_state &= ~KQ_SLEEP; 1490 wakeup(kq); 1491 } 1492 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1493 kq->kq_state &= ~KQ_SEL; 1494 selwakeuppri(&kq->kq_sel, PSOCK); 1495 } 1496 if (!knlist_empty(&kq->kq_sel.si_note)) 1497 kqueue_schedtask(kq); 1498 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1499 pgsigio(&kq->kq_sigio, SIGIO, 0); 1500 } 1501 } 1502 1503 /* 1504 * Walk down a list of knotes, activating them if their event has triggered. 1505 * 1506 * There is a possibility to optimize in the case of one kq watching another. 1507 * Instead of scheduling a task to wake it up, you could pass enough state 1508 * down the chain to make up the parent kqueue. Make this code functional 1509 * first. 1510 */ 1511 void 1512 knote(struct knlist *list, long hint, int islocked) 1513 { 1514 struct kqueue *kq; 1515 struct knote *kn; 1516 1517 if (list == NULL) 1518 return; 1519 1520 KNL_ASSERT_LOCK(list, islocked); 1521 1522 if (!islocked) 1523 list->kl_lock(list->kl_lockarg); 1524 1525 /* 1526 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1527 * the kqueue scheduling, but this will introduce four 1528 * lock/unlock's for each knote to test. If we do, continue to use 1529 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1530 * only safe if you want to remove the current item, which we are 1531 * not doing. 1532 */ 1533 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1534 kq = kn->kn_kq; 1535 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1536 KQ_LOCK(kq); 1537 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1538 kn->kn_status |= KN_HASKQLOCK; 1539 if (kn->kn_fop->f_event(kn, hint)) 1540 KNOTE_ACTIVATE(kn, 1); 1541 kn->kn_status &= ~KN_HASKQLOCK; 1542 } 1543 KQ_UNLOCK(kq); 1544 } 1545 kq = NULL; 1546 } 1547 if (!islocked) 1548 list->kl_unlock(list->kl_lockarg); 1549 } 1550 1551 /* 1552 * add a knote to a knlist 1553 */ 1554 void 1555 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1556 { 1557 KNL_ASSERT_LOCK(knl, islocked); 1558 KQ_NOTOWNED(kn->kn_kq); 1559 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1560 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1561 if (!islocked) 1562 knl->kl_lock(knl->kl_lockarg); 1563 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1564 if (!islocked) 1565 knl->kl_unlock(knl->kl_lockarg); 1566 KQ_LOCK(kn->kn_kq); 1567 kn->kn_knlist = knl; 1568 kn->kn_status &= ~KN_DETACHED; 1569 KQ_UNLOCK(kn->kn_kq); 1570 } 1571 1572 static void 1573 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1574 { 1575 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1576 KNL_ASSERT_LOCK(knl, knlislocked); 1577 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1578 if (!kqislocked) 1579 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1580 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1581 if (!knlislocked) 1582 knl->kl_lock(knl->kl_lockarg); 1583 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1584 kn->kn_knlist = NULL; 1585 if (!knlislocked) 1586 knl->kl_unlock(knl->kl_lockarg); 1587 if (!kqislocked) 1588 KQ_LOCK(kn->kn_kq); 1589 kn->kn_status |= KN_DETACHED; 1590 if (!kqislocked) 1591 KQ_UNLOCK(kn->kn_kq); 1592 } 1593 1594 /* 1595 * remove all knotes from a specified klist 1596 */ 1597 void 1598 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1599 { 1600 1601 knlist_remove_kq(knl, kn, islocked, 0); 1602 } 1603 1604 /* 1605 * remove knote from a specified klist while in f_event handler. 1606 */ 1607 void 1608 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1609 { 1610 1611 knlist_remove_kq(knl, kn, 1, 1612 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1613 } 1614 1615 int 1616 knlist_empty(struct knlist *knl) 1617 { 1618 KNL_ASSERT_LOCKED(knl); 1619 return SLIST_EMPTY(&knl->kl_list); 1620 } 1621 1622 static struct mtx knlist_lock; 1623 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1624 MTX_DEF); 1625 static void knlist_mtx_lock(void *arg); 1626 static void knlist_mtx_unlock(void *arg); 1627 static int knlist_mtx_locked(void *arg); 1628 1629 static void 1630 knlist_mtx_lock(void *arg) 1631 { 1632 mtx_lock((struct mtx *)arg); 1633 } 1634 1635 static void 1636 knlist_mtx_unlock(void *arg) 1637 { 1638 mtx_unlock((struct mtx *)arg); 1639 } 1640 1641 static int 1642 knlist_mtx_locked(void *arg) 1643 { 1644 return (mtx_owned((struct mtx *)arg)); 1645 } 1646 1647 void 1648 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 1649 void (*kl_unlock)(void *), int (*kl_locked)(void *)) 1650 { 1651 1652 if (lock == NULL) 1653 knl->kl_lockarg = &knlist_lock; 1654 else 1655 knl->kl_lockarg = lock; 1656 1657 if (kl_lock == NULL) 1658 knl->kl_lock = knlist_mtx_lock; 1659 else 1660 knl->kl_lock = kl_lock; 1661 if (kl_unlock == NULL) 1662 knl->kl_unlock = knlist_mtx_unlock; 1663 else 1664 knl->kl_unlock = kl_unlock; 1665 if (kl_locked == NULL) 1666 knl->kl_locked = knlist_mtx_locked; 1667 else 1668 knl->kl_locked = kl_locked; 1669 1670 SLIST_INIT(&knl->kl_list); 1671 } 1672 1673 void 1674 knlist_destroy(struct knlist *knl) 1675 { 1676 1677 #ifdef INVARIANTS 1678 /* 1679 * if we run across this error, we need to find the offending 1680 * driver and have it call knlist_clear. 1681 */ 1682 if (!SLIST_EMPTY(&knl->kl_list)) 1683 printf("WARNING: destroying knlist w/ knotes on it!\n"); 1684 #endif 1685 1686 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 1687 SLIST_INIT(&knl->kl_list); 1688 } 1689 1690 /* 1691 * Even if we are locked, we may need to drop the lock to allow any influx 1692 * knotes time to "settle". 1693 */ 1694 void 1695 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 1696 { 1697 struct knote *kn, *kn2; 1698 struct kqueue *kq; 1699 1700 if (islocked) 1701 KNL_ASSERT_LOCKED(knl); 1702 else { 1703 KNL_ASSERT_UNLOCKED(knl); 1704 again: /* need to reaquire lock since we have dropped it */ 1705 knl->kl_lock(knl->kl_lockarg); 1706 } 1707 1708 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 1709 kq = kn->kn_kq; 1710 KQ_LOCK(kq); 1711 if ((kn->kn_status & KN_INFLUX)) { 1712 KQ_UNLOCK(kq); 1713 continue; 1714 } 1715 knlist_remove_kq(knl, kn, 1, 1); 1716 if (killkn) { 1717 kn->kn_status |= KN_INFLUX | KN_DETACHED; 1718 KQ_UNLOCK(kq); 1719 knote_drop(kn, td); 1720 } else { 1721 /* Make sure cleared knotes disappear soon */ 1722 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 1723 KQ_UNLOCK(kq); 1724 } 1725 kq = NULL; 1726 } 1727 1728 if (!SLIST_EMPTY(&knl->kl_list)) { 1729 /* there are still KN_INFLUX remaining */ 1730 kn = SLIST_FIRST(&knl->kl_list); 1731 kq = kn->kn_kq; 1732 KQ_LOCK(kq); 1733 KASSERT(kn->kn_status & KN_INFLUX, 1734 ("knote removed w/o list lock")); 1735 knl->kl_unlock(knl->kl_lockarg); 1736 kq->kq_state |= KQ_FLUXWAIT; 1737 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 1738 kq = NULL; 1739 goto again; 1740 } 1741 1742 if (islocked) 1743 KNL_ASSERT_LOCKED(knl); 1744 else { 1745 knl->kl_unlock(knl->kl_lockarg); 1746 KNL_ASSERT_UNLOCKED(knl); 1747 } 1748 } 1749 1750 /* 1751 * remove all knotes referencing a specified fd 1752 * must be called with FILEDESC lock. This prevents a race where a new fd 1753 * comes along and occupies the entry and we attach a knote to the fd. 1754 */ 1755 void 1756 knote_fdclose(struct thread *td, int fd) 1757 { 1758 struct filedesc *fdp = td->td_proc->p_fd; 1759 struct kqueue *kq; 1760 struct knote *kn; 1761 int influx; 1762 1763 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1764 1765 /* 1766 * We shouldn't have to worry about new kevents appearing on fd 1767 * since filedesc is locked. 1768 */ 1769 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 1770 KQ_LOCK(kq); 1771 1772 again: 1773 influx = 0; 1774 while (kq->kq_knlistsize > fd && 1775 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 1776 if (kn->kn_status & KN_INFLUX) { 1777 /* someone else might be waiting on our knote */ 1778 if (influx) 1779 wakeup(kq); 1780 kq->kq_state |= KQ_FLUXWAIT; 1781 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 1782 goto again; 1783 } 1784 kn->kn_status |= KN_INFLUX; 1785 KQ_UNLOCK(kq); 1786 if (!(kn->kn_status & KN_DETACHED)) 1787 kn->kn_fop->f_detach(kn); 1788 knote_drop(kn, td); 1789 influx = 1; 1790 KQ_LOCK(kq); 1791 } 1792 KQ_UNLOCK_FLUX(kq); 1793 } 1794 } 1795 1796 static int 1797 knote_attach(struct knote *kn, struct kqueue *kq) 1798 { 1799 struct klist *list; 1800 1801 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 1802 KQ_OWNED(kq); 1803 1804 if (kn->kn_fop->f_isfd) { 1805 if (kn->kn_id >= kq->kq_knlistsize) 1806 return ENOMEM; 1807 list = &kq->kq_knlist[kn->kn_id]; 1808 } else { 1809 if (kq->kq_knhash == NULL) 1810 return ENOMEM; 1811 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1812 } 1813 1814 SLIST_INSERT_HEAD(list, kn, kn_link); 1815 1816 return 0; 1817 } 1818 1819 /* 1820 * knote must already have been detached using the f_detach method. 1821 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 1822 * to prevent other removal. 1823 */ 1824 static void 1825 knote_drop(struct knote *kn, struct thread *td) 1826 { 1827 struct kqueue *kq; 1828 struct klist *list; 1829 1830 kq = kn->kn_kq; 1831 1832 KQ_NOTOWNED(kq); 1833 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 1834 ("knote_drop called without KN_INFLUX set in kn_status")); 1835 1836 KQ_LOCK(kq); 1837 if (kn->kn_fop->f_isfd) 1838 list = &kq->kq_knlist[kn->kn_id]; 1839 else 1840 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1841 1842 if (!SLIST_EMPTY(list)) 1843 SLIST_REMOVE(list, kn, knote, kn_link); 1844 if (kn->kn_status & KN_QUEUED) 1845 knote_dequeue(kn); 1846 KQ_UNLOCK_FLUX(kq); 1847 1848 if (kn->kn_fop->f_isfd) { 1849 fdrop(kn->kn_fp, td); 1850 kn->kn_fp = NULL; 1851 } 1852 kqueue_fo_release(kn->kn_kevent.filter); 1853 kn->kn_fop = NULL; 1854 knote_free(kn); 1855 } 1856 1857 static void 1858 knote_enqueue(struct knote *kn) 1859 { 1860 struct kqueue *kq = kn->kn_kq; 1861 1862 KQ_OWNED(kn->kn_kq); 1863 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1864 1865 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1866 kn->kn_status |= KN_QUEUED; 1867 kq->kq_count++; 1868 kqueue_wakeup(kq); 1869 } 1870 1871 static void 1872 knote_dequeue(struct knote *kn) 1873 { 1874 struct kqueue *kq = kn->kn_kq; 1875 1876 KQ_OWNED(kn->kn_kq); 1877 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1878 1879 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1880 kn->kn_status &= ~KN_QUEUED; 1881 kq->kq_count--; 1882 } 1883 1884 static void 1885 knote_init(void) 1886 { 1887 1888 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 1889 NULL, NULL, UMA_ALIGN_PTR, 0); 1890 } 1891 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL) 1892 1893 static struct knote * 1894 knote_alloc(int waitok) 1895 { 1896 return ((struct knote *)uma_zalloc(knote_zone, 1897 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 1898 } 1899 1900 static void 1901 knote_free(struct knote *kn) 1902 { 1903 if (kn != NULL) 1904 uma_zfree(knote_zone, kn); 1905 } 1906