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