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