1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/kern/kern_event.c,v 1.2.2.10 2004/04/04 07:03:14 cperciva Exp $ 27 * $DragonFly: src/sys/kern/kern_event.c,v 1.33 2007/02/03 17:05:57 corecode Exp $ 28 */ 29 30 #include <sys/param.h> 31 #include <sys/systm.h> 32 #include <sys/kernel.h> 33 #include <sys/proc.h> 34 #include <sys/malloc.h> 35 #include <sys/unistd.h> 36 #include <sys/file.h> 37 #include <sys/lock.h> 38 #include <sys/fcntl.h> 39 #include <sys/queue.h> 40 #include <sys/event.h> 41 #include <sys/eventvar.h> 42 #include <sys/protosw.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 #include <sys/stat.h> 46 #include <sys/sysctl.h> 47 #include <sys/sysproto.h> 48 #include <sys/thread.h> 49 #include <sys/uio.h> 50 #include <sys/signalvar.h> 51 #include <sys/filio.h> 52 #include <sys/ktr.h> 53 54 #include <sys/thread2.h> 55 #include <sys/file2.h> 56 #include <sys/mplock2.h> 57 58 /* 59 * Global token for kqueue subsystem 60 */ 61 #if 0 62 struct lwkt_token kq_token = LWKT_TOKEN_INITIALIZER(kq_token); 63 SYSCTL_LONG(_lwkt, OID_AUTO, kq_collisions, 64 CTLFLAG_RW, &kq_token.t_collisions, 0, 65 "Collision counter of kq_token"); 66 #endif 67 68 MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 69 70 struct kevent_copyin_args { 71 struct kevent_args *ka; 72 int pchanges; 73 }; 74 75 static int kqueue_sleep(struct kqueue *kq, struct timespec *tsp); 76 static int kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 77 struct knote *marker); 78 static int kqueue_read(struct file *fp, struct uio *uio, 79 struct ucred *cred, int flags); 80 static int kqueue_write(struct file *fp, struct uio *uio, 81 struct ucred *cred, int flags); 82 static int kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 83 struct ucred *cred, struct sysmsg *msg); 84 static int kqueue_kqfilter(struct file *fp, struct knote *kn); 85 static int kqueue_stat(struct file *fp, struct stat *st, 86 struct ucred *cred); 87 static int kqueue_close(struct file *fp); 88 static void kqueue_wakeup(struct kqueue *kq); 89 static int filter_attach(struct knote *kn); 90 static int filter_event(struct knote *kn, long hint); 91 92 /* 93 * MPSAFE 94 */ 95 static struct fileops kqueueops = { 96 .fo_read = kqueue_read, 97 .fo_write = kqueue_write, 98 .fo_ioctl = kqueue_ioctl, 99 .fo_kqfilter = kqueue_kqfilter, 100 .fo_stat = kqueue_stat, 101 .fo_close = kqueue_close, 102 .fo_shutdown = nofo_shutdown 103 }; 104 105 static void knote_attach(struct knote *kn); 106 static void knote_drop(struct knote *kn); 107 static void knote_detach_and_drop(struct knote *kn); 108 static void knote_enqueue(struct knote *kn); 109 static void knote_dequeue(struct knote *kn); 110 static struct knote *knote_alloc(void); 111 static void knote_free(struct knote *kn); 112 113 static void filt_kqdetach(struct knote *kn); 114 static int filt_kqueue(struct knote *kn, long hint); 115 static int filt_procattach(struct knote *kn); 116 static void filt_procdetach(struct knote *kn); 117 static int filt_proc(struct knote *kn, long hint); 118 static int filt_fileattach(struct knote *kn); 119 static void filt_timerexpire(void *knx); 120 static int filt_timerattach(struct knote *kn); 121 static void filt_timerdetach(struct knote *kn); 122 static int filt_timer(struct knote *kn, long hint); 123 124 static struct filterops file_filtops = 125 { FILTEROP_ISFD, filt_fileattach, NULL, NULL }; 126 static struct filterops kqread_filtops = 127 { FILTEROP_ISFD, NULL, filt_kqdetach, filt_kqueue }; 128 static struct filterops proc_filtops = 129 { 0, filt_procattach, filt_procdetach, filt_proc }; 130 static struct filterops timer_filtops = 131 { 0, filt_timerattach, filt_timerdetach, filt_timer }; 132 133 static int kq_ncallouts = 0; 134 static int kq_calloutmax = (4 * 1024); 135 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 136 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 137 static int kq_checkloop = 1000000; 138 SYSCTL_INT(_kern, OID_AUTO, kq_checkloop, CTLFLAG_RW, 139 &kq_checkloop, 0, "Maximum number of callouts allocated for kqueue"); 140 141 #define KNOTE_ACTIVATE(kn) do { \ 142 kn->kn_status |= KN_ACTIVE; \ 143 if ((kn->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 144 knote_enqueue(kn); \ 145 } while(0) 146 147 #define KN_HASHSIZE 64 /* XXX should be tunable */ 148 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 149 150 extern struct filterops aio_filtops; 151 extern struct filterops sig_filtops; 152 153 /* 154 * Table for for all system-defined filters. 155 */ 156 static struct filterops *sysfilt_ops[] = { 157 &file_filtops, /* EVFILT_READ */ 158 &file_filtops, /* EVFILT_WRITE */ 159 &aio_filtops, /* EVFILT_AIO */ 160 &file_filtops, /* EVFILT_VNODE */ 161 &proc_filtops, /* EVFILT_PROC */ 162 &sig_filtops, /* EVFILT_SIGNAL */ 163 &timer_filtops, /* EVFILT_TIMER */ 164 &file_filtops, /* EVFILT_EXCEPT */ 165 }; 166 167 static int 168 filt_fileattach(struct knote *kn) 169 { 170 return (fo_kqfilter(kn->kn_fp, kn)); 171 } 172 173 /* 174 * MPSAFE 175 */ 176 static int 177 kqueue_kqfilter(struct file *fp, struct knote *kn) 178 { 179 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 180 181 if (kn->kn_filter != EVFILT_READ) 182 return (EOPNOTSUPP); 183 184 kn->kn_fop = &kqread_filtops; 185 knote_insert(&kq->kq_kqinfo.ki_note, kn); 186 return (0); 187 } 188 189 static void 190 filt_kqdetach(struct knote *kn) 191 { 192 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 193 194 knote_remove(&kq->kq_kqinfo.ki_note, kn); 195 } 196 197 /*ARGSUSED*/ 198 static int 199 filt_kqueue(struct knote *kn, long hint) 200 { 201 struct kqueue *kq = (struct kqueue *)kn->kn_fp->f_data; 202 203 kn->kn_data = kq->kq_count; 204 return (kn->kn_data > 0); 205 } 206 207 static int 208 filt_procattach(struct knote *kn) 209 { 210 struct proc *p; 211 int immediate; 212 213 immediate = 0; 214 p = pfind(kn->kn_id); 215 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 216 p = zpfind(kn->kn_id); 217 immediate = 1; 218 } 219 if (p == NULL) { 220 return (ESRCH); 221 } 222 if (!PRISON_CHECK(curthread->td_ucred, p->p_ucred)) { 223 if (p) 224 PRELE(p); 225 return (EACCES); 226 } 227 228 lwkt_gettoken(&p->p_token); 229 kn->kn_ptr.p_proc = p; 230 kn->kn_flags |= EV_CLEAR; /* automatically set */ 231 232 /* 233 * internal flag indicating registration done by kernel 234 */ 235 if (kn->kn_flags & EV_FLAG1) { 236 kn->kn_data = kn->kn_sdata; /* ppid */ 237 kn->kn_fflags = NOTE_CHILD; 238 kn->kn_flags &= ~EV_FLAG1; 239 } 240 241 knote_insert(&p->p_klist, kn); 242 243 /* 244 * Immediately activate any exit notes if the target process is a 245 * zombie. This is necessary to handle the case where the target 246 * process, e.g. a child, dies before the kevent is negistered. 247 */ 248 if (immediate && filt_proc(kn, NOTE_EXIT)) 249 KNOTE_ACTIVATE(kn); 250 lwkt_reltoken(&p->p_token); 251 PRELE(p); 252 253 return (0); 254 } 255 256 /* 257 * The knote may be attached to a different process, which may exit, 258 * leaving nothing for the knote to be attached to. So when the process 259 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 260 * it will be deleted when read out. However, as part of the knote deletion, 261 * this routine is called, so a check is needed to avoid actually performing 262 * a detach, because the original process does not exist any more. 263 */ 264 static void 265 filt_procdetach(struct knote *kn) 266 { 267 struct proc *p; 268 269 if (kn->kn_status & KN_DETACHED) 270 return; 271 /* XXX locking? take proc_token here? */ 272 p = kn->kn_ptr.p_proc; 273 knote_remove(&p->p_klist, kn); 274 } 275 276 static int 277 filt_proc(struct knote *kn, long hint) 278 { 279 u_int event; 280 281 /* 282 * mask off extra data 283 */ 284 event = (u_int)hint & NOTE_PCTRLMASK; 285 286 /* 287 * if the user is interested in this event, record it. 288 */ 289 if (kn->kn_sfflags & event) 290 kn->kn_fflags |= event; 291 292 /* 293 * Process is gone, so flag the event as finished. Detach the 294 * knote from the process now because the process will be poof, 295 * gone later on. 296 */ 297 if (event == NOTE_EXIT) { 298 struct proc *p = kn->kn_ptr.p_proc; 299 if ((kn->kn_status & KN_DETACHED) == 0) { 300 knote_remove(&p->p_klist, kn); 301 kn->kn_status |= KN_DETACHED; 302 kn->kn_data = p->p_xstat; 303 kn->kn_ptr.p_proc = NULL; 304 } 305 kn->kn_flags |= (EV_EOF | EV_NODATA | EV_ONESHOT); 306 return (1); 307 } 308 309 /* 310 * process forked, and user wants to track the new process, 311 * so attach a new knote to it, and immediately report an 312 * event with the parent's pid. 313 */ 314 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 315 struct kevent kev; 316 int error; 317 318 /* 319 * register knote with new process. 320 */ 321 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 322 kev.filter = kn->kn_filter; 323 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 324 kev.fflags = kn->kn_sfflags; 325 kev.data = kn->kn_id; /* parent */ 326 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 327 error = kqueue_register(kn->kn_kq, &kev); 328 if (error) 329 kn->kn_fflags |= NOTE_TRACKERR; 330 } 331 332 return (kn->kn_fflags != 0); 333 } 334 335 /* 336 * The callout interlocks with callout_terminate() but can still 337 * race a deletion so if KN_DELETING is set we just don't touch 338 * the knote. 339 */ 340 static void 341 filt_timerexpire(void *knx) 342 { 343 struct lwkt_token *tok; 344 struct knote *kn = knx; 345 struct callout *calloutp; 346 struct timeval tv; 347 int tticks; 348 349 tok = lwkt_token_pool_lookup(kn->kn_kq); 350 lwkt_gettoken(tok); 351 if ((kn->kn_status & KN_DELETING) == 0) { 352 kn->kn_data++; 353 KNOTE_ACTIVATE(kn); 354 355 if ((kn->kn_flags & EV_ONESHOT) == 0) { 356 tv.tv_sec = kn->kn_sdata / 1000; 357 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 358 tticks = tvtohz_high(&tv); 359 calloutp = (struct callout *)kn->kn_hook; 360 callout_reset(calloutp, tticks, filt_timerexpire, kn); 361 } 362 } 363 lwkt_reltoken(tok); 364 } 365 366 /* 367 * data contains amount of time to sleep, in milliseconds 368 */ 369 static int 370 filt_timerattach(struct knote *kn) 371 { 372 struct callout *calloutp; 373 struct timeval tv; 374 int tticks; 375 376 if (kq_ncallouts >= kq_calloutmax) { 377 kn->kn_hook = NULL; 378 return (ENOMEM); 379 } 380 kq_ncallouts++; 381 382 tv.tv_sec = kn->kn_sdata / 1000; 383 tv.tv_usec = (kn->kn_sdata % 1000) * 1000; 384 tticks = tvtohz_high(&tv); 385 386 kn->kn_flags |= EV_CLEAR; /* automatically set */ 387 MALLOC(calloutp, struct callout *, sizeof(*calloutp), 388 M_KQUEUE, M_WAITOK); 389 callout_init(calloutp); 390 kn->kn_hook = (caddr_t)calloutp; 391 callout_reset(calloutp, tticks, filt_timerexpire, kn); 392 393 return (0); 394 } 395 396 /* 397 * This function is called with the knote flagged locked but it is 398 * still possible to race a callout event due to the callback blocking. 399 * We must call callout_terminate() instead of callout_stop() to deal 400 * with the race. 401 */ 402 static void 403 filt_timerdetach(struct knote *kn) 404 { 405 struct callout *calloutp; 406 407 calloutp = (struct callout *)kn->kn_hook; 408 callout_terminate(calloutp); 409 FREE(calloutp, M_KQUEUE); 410 kq_ncallouts--; 411 } 412 413 static int 414 filt_timer(struct knote *kn, long hint) 415 { 416 417 return (kn->kn_data != 0); 418 } 419 420 /* 421 * Acquire a knote, return non-zero on success, 0 on failure. 422 * 423 * If we cannot acquire the knote we sleep and return 0. The knote 424 * may be stale on return in this case and the caller must restart 425 * whatever loop they are in. 426 * 427 * Related kq token must be held. 428 */ 429 static __inline 430 int 431 knote_acquire(struct knote *kn) 432 { 433 if (kn->kn_status & KN_PROCESSING) { 434 kn->kn_status |= KN_WAITING | KN_REPROCESS; 435 tsleep(kn, 0, "kqepts", hz); 436 /* knote may be stale now */ 437 return(0); 438 } 439 kn->kn_status |= KN_PROCESSING; 440 return(1); 441 } 442 443 /* 444 * Release an acquired knote, clearing KN_PROCESSING and handling any 445 * KN_REPROCESS events. 446 * 447 * Caller must be holding the related kq token 448 * 449 * Non-zero is returned if the knote is destroyed. 450 */ 451 static __inline 452 int 453 knote_release(struct knote *kn) 454 { 455 while (kn->kn_status & KN_REPROCESS) { 456 kn->kn_status &= ~KN_REPROCESS; 457 if (kn->kn_status & KN_WAITING) { 458 kn->kn_status &= ~KN_WAITING; 459 wakeup(kn); 460 } 461 if (kn->kn_status & KN_DELETING) { 462 knote_detach_and_drop(kn); 463 return(1); 464 /* NOT REACHED */ 465 } 466 if (filter_event(kn, 0)) 467 KNOTE_ACTIVATE(kn); 468 } 469 kn->kn_status &= ~KN_PROCESSING; 470 return(0); 471 } 472 473 /* 474 * Initialize a kqueue. 475 * 476 * NOTE: The lwp/proc code initializes a kqueue for select/poll ops. 477 * 478 * MPSAFE 479 */ 480 void 481 kqueue_init(struct kqueue *kq, struct filedesc *fdp) 482 { 483 TAILQ_INIT(&kq->kq_knpend); 484 TAILQ_INIT(&kq->kq_knlist); 485 kq->kq_count = 0; 486 kq->kq_fdp = fdp; 487 SLIST_INIT(&kq->kq_kqinfo.ki_note); 488 } 489 490 /* 491 * Terminate a kqueue. Freeing the actual kq itself is left up to the 492 * caller (it might be embedded in a lwp so we don't do it here). 493 * 494 * The kq's knlist must be completely eradicated so block on any 495 * processing races. 496 */ 497 void 498 kqueue_terminate(struct kqueue *kq) 499 { 500 struct lwkt_token *tok; 501 struct knote *kn; 502 503 tok = lwkt_token_pool_lookup(kq); 504 lwkt_gettoken(tok); 505 while ((kn = TAILQ_FIRST(&kq->kq_knlist)) != NULL) { 506 if (knote_acquire(kn)) 507 knote_detach_and_drop(kn); 508 } 509 if (kq->kq_knhash) { 510 kfree(kq->kq_knhash, M_KQUEUE); 511 kq->kq_knhash = NULL; 512 kq->kq_knhashmask = 0; 513 } 514 lwkt_reltoken(tok); 515 } 516 517 /* 518 * MPSAFE 519 */ 520 int 521 sys_kqueue(struct kqueue_args *uap) 522 { 523 struct thread *td = curthread; 524 struct kqueue *kq; 525 struct file *fp; 526 int fd, error; 527 528 error = falloc(td->td_lwp, &fp, &fd); 529 if (error) 530 return (error); 531 fp->f_flag = FREAD | FWRITE; 532 fp->f_type = DTYPE_KQUEUE; 533 fp->f_ops = &kqueueops; 534 535 kq = kmalloc(sizeof(struct kqueue), M_KQUEUE, M_WAITOK | M_ZERO); 536 kqueue_init(kq, td->td_proc->p_fd); 537 fp->f_data = kq; 538 539 fsetfd(kq->kq_fdp, fp, fd); 540 uap->sysmsg_result = fd; 541 fdrop(fp); 542 return (error); 543 } 544 545 /* 546 * Copy 'count' items into the destination list pointed to by uap->eventlist. 547 */ 548 static int 549 kevent_copyout(void *arg, struct kevent *kevp, int count, int *res) 550 { 551 struct kevent_copyin_args *kap; 552 int error; 553 554 kap = (struct kevent_copyin_args *)arg; 555 556 error = copyout(kevp, kap->ka->eventlist, count * sizeof(*kevp)); 557 if (error == 0) { 558 kap->ka->eventlist += count; 559 *res += count; 560 } else { 561 *res = -1; 562 } 563 564 return (error); 565 } 566 567 /* 568 * Copy at most 'max' items from the list pointed to by kap->changelist, 569 * return number of items in 'events'. 570 */ 571 static int 572 kevent_copyin(void *arg, struct kevent *kevp, int max, int *events) 573 { 574 struct kevent_copyin_args *kap; 575 int error, count; 576 577 kap = (struct kevent_copyin_args *)arg; 578 579 count = min(kap->ka->nchanges - kap->pchanges, max); 580 error = copyin(kap->ka->changelist, kevp, count * sizeof *kevp); 581 if (error == 0) { 582 kap->ka->changelist += count; 583 kap->pchanges += count; 584 *events = count; 585 } 586 587 return (error); 588 } 589 590 /* 591 * MPSAFE 592 */ 593 int 594 kern_kevent(struct kqueue *kq, int nevents, int *res, void *uap, 595 k_copyin_fn kevent_copyinfn, k_copyout_fn kevent_copyoutfn, 596 struct timespec *tsp_in) 597 { 598 struct kevent *kevp; 599 struct timespec *tsp; 600 int i, n, total, error, nerrors = 0; 601 int lres; 602 int limit = kq_checkloop; 603 struct kevent kev[KQ_NEVENTS]; 604 struct knote marker; 605 struct lwkt_token *tok; 606 607 tsp = tsp_in; 608 *res = 0; 609 610 tok = lwkt_token_pool_lookup(kq); 611 lwkt_gettoken(tok); 612 for ( ;; ) { 613 n = 0; 614 error = kevent_copyinfn(uap, kev, KQ_NEVENTS, &n); 615 if (error) 616 goto done; 617 if (n == 0) 618 break; 619 for (i = 0; i < n; i++) { 620 kevp = &kev[i]; 621 kevp->flags &= ~EV_SYSFLAGS; 622 error = kqueue_register(kq, kevp); 623 624 /* 625 * If a registration returns an error we 626 * immediately post the error. The kevent() 627 * call itself will fail with the error if 628 * no space is available for posting. 629 * 630 * Such errors normally bypass the timeout/blocking 631 * code. However, if the copyoutfn function refuses 632 * to post the error (see sys_poll()), then we 633 * ignore it too. 634 */ 635 if (error) { 636 kevp->flags = EV_ERROR; 637 kevp->data = error; 638 lres = *res; 639 kevent_copyoutfn(uap, kevp, 1, res); 640 if (*res < 0) { 641 goto done; 642 } else if (lres != *res) { 643 nevents--; 644 nerrors++; 645 } 646 } 647 } 648 } 649 if (nerrors) { 650 error = 0; 651 goto done; 652 } 653 654 /* 655 * Acquire/wait for events - setup timeout 656 */ 657 if (tsp != NULL) { 658 struct timespec ats; 659 660 if (tsp->tv_sec || tsp->tv_nsec) { 661 nanouptime(&ats); 662 timespecadd(tsp, &ats); /* tsp = target time */ 663 } 664 } 665 666 /* 667 * Loop as required. 668 * 669 * Collect as many events as we can. Sleeping on successive 670 * loops is disabled if copyoutfn has incremented (*res). 671 * 672 * The loop stops if an error occurs, all events have been 673 * scanned (the marker has been reached), or fewer than the 674 * maximum number of events is found. 675 * 676 * The copyoutfn function does not have to increment (*res) in 677 * order for the loop to continue. 678 * 679 * NOTE: doselect() usually passes 0x7FFFFFFF for nevents. 680 */ 681 total = 0; 682 error = 0; 683 marker.kn_filter = EVFILT_MARKER; 684 marker.kn_status = KN_PROCESSING; 685 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 686 while ((n = nevents - total) > 0) { 687 if (n > KQ_NEVENTS) 688 n = KQ_NEVENTS; 689 690 /* 691 * If no events are pending sleep until timeout (if any) 692 * or an event occurs. 693 * 694 * After the sleep completes the marker is moved to the 695 * end of the list, making any received events available 696 * to our scan. 697 */ 698 if (kq->kq_count == 0 && *res == 0) { 699 error = kqueue_sleep(kq, tsp); 700 if (error) 701 break; 702 703 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 704 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 705 } 706 707 /* 708 * Process all received events 709 * Account for all non-spurious events in our total 710 */ 711 i = kqueue_scan(kq, kev, n, &marker); 712 if (i) { 713 lres = *res; 714 error = kevent_copyoutfn(uap, kev, i, res); 715 total += *res - lres; 716 if (error) 717 break; 718 } 719 if (limit && --limit == 0) 720 panic("kqueue: checkloop failed i=%d", i); 721 722 /* 723 * Normally when fewer events are returned than requested 724 * we can stop. However, if only spurious events were 725 * collected the copyout will not bump (*res) and we have 726 * to continue. 727 */ 728 if (i < n && *res) 729 break; 730 731 /* 732 * Deal with an edge case where spurious events can cause 733 * a loop to occur without moving the marker. This can 734 * prevent kqueue_scan() from picking up new events which 735 * race us. We must be sure to move the marker for this 736 * case. 737 * 738 * NOTE: We do not want to move the marker if events 739 * were scanned because normal kqueue operations 740 * may reactivate events. Moving the marker in 741 * that case could result in duplicates for the 742 * same event. 743 */ 744 if (i == 0) { 745 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 746 TAILQ_INSERT_TAIL(&kq->kq_knpend, &marker, kn_tqe); 747 } 748 } 749 TAILQ_REMOVE(&kq->kq_knpend, &marker, kn_tqe); 750 751 /* Timeouts do not return EWOULDBLOCK. */ 752 if (error == EWOULDBLOCK) 753 error = 0; 754 755 done: 756 lwkt_reltoken(tok); 757 return (error); 758 } 759 760 /* 761 * MPALMOSTSAFE 762 */ 763 int 764 sys_kevent(struct kevent_args *uap) 765 { 766 struct thread *td = curthread; 767 struct proc *p = td->td_proc; 768 struct timespec ts, *tsp; 769 struct kqueue *kq; 770 struct file *fp = NULL; 771 struct kevent_copyin_args *kap, ka; 772 int error; 773 774 if (uap->timeout) { 775 error = copyin(uap->timeout, &ts, sizeof(ts)); 776 if (error) 777 return (error); 778 tsp = &ts; 779 } else { 780 tsp = NULL; 781 } 782 783 fp = holdfp(p->p_fd, uap->fd, -1); 784 if (fp == NULL) 785 return (EBADF); 786 if (fp->f_type != DTYPE_KQUEUE) { 787 fdrop(fp); 788 return (EBADF); 789 } 790 791 kq = (struct kqueue *)fp->f_data; 792 793 kap = &ka; 794 kap->ka = uap; 795 kap->pchanges = 0; 796 797 error = kern_kevent(kq, uap->nevents, &uap->sysmsg_result, kap, 798 kevent_copyin, kevent_copyout, tsp); 799 800 fdrop(fp); 801 802 return (error); 803 } 804 805 /* 806 * Caller must be holding the kq token 807 */ 808 int 809 kqueue_register(struct kqueue *kq, struct kevent *kev) 810 { 811 struct lwkt_token *tok; 812 struct filedesc *fdp = kq->kq_fdp; 813 struct filterops *fops; 814 struct file *fp = NULL; 815 struct knote *kn = NULL; 816 int error = 0; 817 818 if (kev->filter < 0) { 819 if (kev->filter + EVFILT_SYSCOUNT < 0) 820 return (EINVAL); 821 fops = sysfilt_ops[~kev->filter]; /* to 0-base index */ 822 } else { 823 /* 824 * XXX 825 * filter attach routine is responsible for insuring that 826 * the identifier can be attached to it. 827 */ 828 kprintf("unknown filter: %d\n", kev->filter); 829 return (EINVAL); 830 } 831 832 tok = lwkt_token_pool_lookup(kq); 833 lwkt_gettoken(tok); 834 if (fops->f_flags & FILTEROP_ISFD) { 835 /* validate descriptor */ 836 fp = holdfp(fdp, kev->ident, -1); 837 if (fp == NULL) { 838 lwkt_reltoken(tok); 839 return (EBADF); 840 } 841 lwkt_getpooltoken(&fp->f_klist); 842 again1: 843 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 844 if (kn->kn_kq == kq && 845 kn->kn_filter == kev->filter && 846 kn->kn_id == kev->ident) { 847 if (knote_acquire(kn) == 0) 848 goto again1; 849 break; 850 } 851 } 852 lwkt_relpooltoken(&fp->f_klist); 853 } else { 854 if (kq->kq_knhashmask) { 855 struct klist *list; 856 857 list = &kq->kq_knhash[ 858 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 859 lwkt_getpooltoken(list); 860 again2: 861 SLIST_FOREACH(kn, list, kn_link) { 862 if (kn->kn_id == kev->ident && 863 kn->kn_filter == kev->filter) { 864 if (knote_acquire(kn) == 0) 865 goto again2; 866 break; 867 } 868 } 869 lwkt_relpooltoken(list); 870 } 871 } 872 873 /* 874 * NOTE: At this point if kn is non-NULL we will have acquired 875 * it and set KN_PROCESSING. 876 */ 877 if (kn == NULL && ((kev->flags & EV_ADD) == 0)) { 878 error = ENOENT; 879 goto done; 880 } 881 882 /* 883 * kn now contains the matching knote, or NULL if no match 884 */ 885 if (kev->flags & EV_ADD) { 886 if (kn == NULL) { 887 kn = knote_alloc(); 888 if (kn == NULL) { 889 error = ENOMEM; 890 goto done; 891 } 892 kn->kn_fp = fp; 893 kn->kn_kq = kq; 894 kn->kn_fop = fops; 895 896 /* 897 * apply reference count to knote structure, and 898 * do not release it at the end of this routine. 899 */ 900 fp = NULL; 901 902 kn->kn_sfflags = kev->fflags; 903 kn->kn_sdata = kev->data; 904 kev->fflags = 0; 905 kev->data = 0; 906 kn->kn_kevent = *kev; 907 908 /* 909 * KN_PROCESSING prevents the knote from getting 910 * ripped out from under us while we are trying 911 * to attach it, in case the attach blocks. 912 */ 913 kn->kn_status = KN_PROCESSING; 914 knote_attach(kn); 915 if ((error = filter_attach(kn)) != 0) { 916 kn->kn_status |= KN_DELETING | KN_REPROCESS; 917 knote_drop(kn); 918 goto done; 919 } 920 921 /* 922 * Interlock against close races which either tried 923 * to remove our knote while we were blocked or missed 924 * it entirely prior to our attachment. We do not 925 * want to end up with a knote on a closed descriptor. 926 */ 927 if ((fops->f_flags & FILTEROP_ISFD) && 928 checkfdclosed(fdp, kev->ident, kn->kn_fp)) { 929 kn->kn_status |= KN_DELETING | KN_REPROCESS; 930 } 931 } else { 932 /* 933 * The user may change some filter values after the 934 * initial EV_ADD, but doing so will not reset any 935 * filter which have already been triggered. 936 */ 937 KKASSERT(kn->kn_status & KN_PROCESSING); 938 kn->kn_sfflags = kev->fflags; 939 kn->kn_sdata = kev->data; 940 kn->kn_kevent.udata = kev->udata; 941 } 942 943 /* 944 * Execute the filter event to immediately activate the 945 * knote if necessary. If reprocessing events are pending 946 * due to blocking above we do not run the filter here 947 * but instead let knote_release() do it. Otherwise we 948 * might run the filter on a deleted event. 949 */ 950 if ((kn->kn_status & KN_REPROCESS) == 0) { 951 if (filter_event(kn, 0)) 952 KNOTE_ACTIVATE(kn); 953 } 954 } else if (kev->flags & EV_DELETE) { 955 /* 956 * Delete the existing knote 957 */ 958 knote_detach_and_drop(kn); 959 goto done; 960 } 961 962 /* 963 * Disablement does not deactivate a knote here. 964 */ 965 if ((kev->flags & EV_DISABLE) && 966 ((kn->kn_status & KN_DISABLED) == 0)) { 967 kn->kn_status |= KN_DISABLED; 968 } 969 970 /* 971 * Re-enablement may have to immediately enqueue an active knote. 972 */ 973 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 974 kn->kn_status &= ~KN_DISABLED; 975 if ((kn->kn_status & KN_ACTIVE) && 976 ((kn->kn_status & KN_QUEUED) == 0)) { 977 knote_enqueue(kn); 978 } 979 } 980 981 /* 982 * Handle any required reprocessing 983 */ 984 knote_release(kn); 985 /* kn may be invalid now */ 986 987 done: 988 lwkt_reltoken(tok); 989 if (fp != NULL) 990 fdrop(fp); 991 return (error); 992 } 993 994 /* 995 * Block as necessary until the target time is reached. 996 * If tsp is NULL we block indefinitely. If tsp->ts_secs/nsecs are both 997 * 0 we do not block at all. 998 * 999 * Caller must be holding the kq token. 1000 */ 1001 static int 1002 kqueue_sleep(struct kqueue *kq, struct timespec *tsp) 1003 { 1004 int error = 0; 1005 1006 if (tsp == NULL) { 1007 kq->kq_state |= KQ_SLEEP; 1008 error = tsleep(kq, PCATCH, "kqread", 0); 1009 } else if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) { 1010 error = EWOULDBLOCK; 1011 } else { 1012 struct timespec ats; 1013 struct timespec atx = *tsp; 1014 int timeout; 1015 1016 nanouptime(&ats); 1017 timespecsub(&atx, &ats); 1018 if (ats.tv_sec < 0) { 1019 error = EWOULDBLOCK; 1020 } else { 1021 timeout = atx.tv_sec > 24 * 60 * 60 ? 1022 24 * 60 * 60 * hz : tstohz_high(&atx); 1023 kq->kq_state |= KQ_SLEEP; 1024 error = tsleep(kq, PCATCH, "kqread", timeout); 1025 } 1026 } 1027 1028 /* don't restart after signals... */ 1029 if (error == ERESTART) 1030 return (EINTR); 1031 1032 return (error); 1033 } 1034 1035 /* 1036 * Scan the kqueue, return the number of active events placed in kevp up 1037 * to count. 1038 * 1039 * Continuous mode events may get recycled, do not continue scanning past 1040 * marker unless no events have been collected. 1041 * 1042 * Caller must be holding the kq token 1043 */ 1044 static int 1045 kqueue_scan(struct kqueue *kq, struct kevent *kevp, int count, 1046 struct knote *marker) 1047 { 1048 struct knote *kn, local_marker; 1049 int total; 1050 1051 total = 0; 1052 local_marker.kn_filter = EVFILT_MARKER; 1053 local_marker.kn_status = KN_PROCESSING; 1054 1055 /* 1056 * Collect events. 1057 */ 1058 TAILQ_INSERT_HEAD(&kq->kq_knpend, &local_marker, kn_tqe); 1059 while (count) { 1060 kn = TAILQ_NEXT(&local_marker, kn_tqe); 1061 if (kn->kn_filter == EVFILT_MARKER) { 1062 /* Marker reached, we are done */ 1063 if (kn == marker) 1064 break; 1065 1066 /* Move local marker past some other threads marker */ 1067 kn = TAILQ_NEXT(kn, kn_tqe); 1068 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1069 TAILQ_INSERT_BEFORE(kn, &local_marker, kn_tqe); 1070 continue; 1071 } 1072 1073 /* 1074 * We can't skip a knote undergoing processing, otherwise 1075 * we risk not returning it when the user process expects 1076 * it should be returned. Sleep and retry. 1077 */ 1078 if (knote_acquire(kn) == 0) 1079 continue; 1080 1081 /* 1082 * Remove the event for processing. 1083 * 1084 * WARNING! We must leave KN_QUEUED set to prevent the 1085 * event from being KNOTE_ACTIVATE()d while 1086 * the queue state is in limbo, in case we 1087 * block. 1088 * 1089 * WARNING! We must set KN_PROCESSING to avoid races 1090 * against deletion or another thread's 1091 * processing. 1092 */ 1093 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1094 kq->kq_count--; 1095 1096 /* 1097 * We have to deal with an extremely important race against 1098 * file descriptor close()s here. The file descriptor can 1099 * disappear MPSAFE, and there is a small window of 1100 * opportunity between that and the call to knote_fdclose(). 1101 * 1102 * If we hit that window here while doselect or dopoll is 1103 * trying to delete a spurious event they will not be able 1104 * to match up the event against a knote and will go haywire. 1105 */ 1106 if ((kn->kn_fop->f_flags & FILTEROP_ISFD) && 1107 checkfdclosed(kq->kq_fdp, kn->kn_kevent.ident, kn->kn_fp)) { 1108 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1109 } 1110 1111 if (kn->kn_status & KN_DISABLED) { 1112 /* 1113 * If disabled we ensure the event is not queued 1114 * but leave its active bit set. On re-enablement 1115 * the event may be immediately triggered. 1116 */ 1117 kn->kn_status &= ~KN_QUEUED; 1118 } else if ((kn->kn_flags & EV_ONESHOT) == 0 && 1119 (kn->kn_status & KN_DELETING) == 0 && 1120 filter_event(kn, 0) == 0) { 1121 /* 1122 * If not running in one-shot mode and the event 1123 * is no longer present we ensure it is removed 1124 * from the queue and ignore it. 1125 */ 1126 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1127 } else { 1128 /* 1129 * Post the event 1130 */ 1131 *kevp++ = kn->kn_kevent; 1132 ++total; 1133 --count; 1134 1135 if (kn->kn_flags & EV_ONESHOT) { 1136 kn->kn_status &= ~KN_QUEUED; 1137 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1138 } else if (kn->kn_flags & EV_CLEAR) { 1139 kn->kn_data = 0; 1140 kn->kn_fflags = 0; 1141 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1142 } else { 1143 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1144 kq->kq_count++; 1145 } 1146 } 1147 1148 /* 1149 * Handle any post-processing states 1150 */ 1151 knote_release(kn); 1152 } 1153 TAILQ_REMOVE(&kq->kq_knpend, &local_marker, kn_tqe); 1154 1155 return (total); 1156 } 1157 1158 /* 1159 * XXX 1160 * This could be expanded to call kqueue_scan, if desired. 1161 * 1162 * MPSAFE 1163 */ 1164 static int 1165 kqueue_read(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1166 { 1167 return (ENXIO); 1168 } 1169 1170 /* 1171 * MPSAFE 1172 */ 1173 static int 1174 kqueue_write(struct file *fp, struct uio *uio, struct ucred *cred, int flags) 1175 { 1176 return (ENXIO); 1177 } 1178 1179 /* 1180 * MPALMOSTSAFE 1181 */ 1182 static int 1183 kqueue_ioctl(struct file *fp, u_long com, caddr_t data, 1184 struct ucred *cred, struct sysmsg *msg) 1185 { 1186 struct lwkt_token *tok; 1187 struct kqueue *kq; 1188 int error; 1189 1190 kq = (struct kqueue *)fp->f_data; 1191 tok = lwkt_token_pool_lookup(kq); 1192 lwkt_gettoken(tok); 1193 1194 switch(com) { 1195 case FIOASYNC: 1196 if (*(int *)data) 1197 kq->kq_state |= KQ_ASYNC; 1198 else 1199 kq->kq_state &= ~KQ_ASYNC; 1200 error = 0; 1201 break; 1202 case FIOSETOWN: 1203 error = fsetown(*(int *)data, &kq->kq_sigio); 1204 break; 1205 default: 1206 error = ENOTTY; 1207 break; 1208 } 1209 lwkt_reltoken(tok); 1210 return (error); 1211 } 1212 1213 /* 1214 * MPSAFE 1215 */ 1216 static int 1217 kqueue_stat(struct file *fp, struct stat *st, struct ucred *cred) 1218 { 1219 struct kqueue *kq = (struct kqueue *)fp->f_data; 1220 1221 bzero((void *)st, sizeof(*st)); 1222 st->st_size = kq->kq_count; 1223 st->st_blksize = sizeof(struct kevent); 1224 st->st_mode = S_IFIFO; 1225 return (0); 1226 } 1227 1228 /* 1229 * MPSAFE 1230 */ 1231 static int 1232 kqueue_close(struct file *fp) 1233 { 1234 struct kqueue *kq = (struct kqueue *)fp->f_data; 1235 1236 kqueue_terminate(kq); 1237 1238 fp->f_data = NULL; 1239 funsetown(&kq->kq_sigio); 1240 1241 kfree(kq, M_KQUEUE); 1242 return (0); 1243 } 1244 1245 static void 1246 kqueue_wakeup(struct kqueue *kq) 1247 { 1248 if (kq->kq_state & KQ_SLEEP) { 1249 kq->kq_state &= ~KQ_SLEEP; 1250 wakeup(kq); 1251 } 1252 KNOTE(&kq->kq_kqinfo.ki_note, 0); 1253 } 1254 1255 /* 1256 * Calls filterops f_attach function, acquiring mplock if filter is not 1257 * marked as FILTEROP_MPSAFE. 1258 * 1259 * Caller must be holding the related kq token 1260 */ 1261 static int 1262 filter_attach(struct knote *kn) 1263 { 1264 int ret; 1265 1266 if (!(kn->kn_fop->f_flags & FILTEROP_MPSAFE)) { 1267 get_mplock(); 1268 ret = kn->kn_fop->f_attach(kn); 1269 rel_mplock(); 1270 } else { 1271 ret = kn->kn_fop->f_attach(kn); 1272 } 1273 1274 return (ret); 1275 } 1276 1277 /* 1278 * Detach the knote and drop it, destroying the knote. 1279 * 1280 * Calls filterops f_detach function, acquiring mplock if filter is not 1281 * marked as FILTEROP_MPSAFE. 1282 * 1283 * Caller must be holding the related kq token 1284 */ 1285 static void 1286 knote_detach_and_drop(struct knote *kn) 1287 { 1288 kn->kn_status |= KN_DELETING | KN_REPROCESS; 1289 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1290 kn->kn_fop->f_detach(kn); 1291 } else { 1292 get_mplock(); 1293 kn->kn_fop->f_detach(kn); 1294 rel_mplock(); 1295 } 1296 knote_drop(kn); 1297 } 1298 1299 /* 1300 * Calls filterops f_event function, acquiring mplock if filter is not 1301 * marked as FILTEROP_MPSAFE. 1302 * 1303 * If the knote is in the middle of being created or deleted we cannot 1304 * safely call the filter op. 1305 * 1306 * Caller must be holding the related kq token 1307 */ 1308 static int 1309 filter_event(struct knote *kn, long hint) 1310 { 1311 int ret; 1312 1313 if (kn->kn_fop->f_flags & FILTEROP_MPSAFE) { 1314 ret = kn->kn_fop->f_event(kn, hint); 1315 } else { 1316 get_mplock(); 1317 ret = kn->kn_fop->f_event(kn, hint); 1318 rel_mplock(); 1319 } 1320 return (ret); 1321 } 1322 1323 /* 1324 * Walk down a list of knotes, activating them if their event has triggered. 1325 * 1326 * If we encounter any knotes which are undergoing processing we just mark 1327 * them for reprocessing and do not try to [re]activate the knote. However, 1328 * if a hint is being passed we have to wait and that makes things a bit 1329 * sticky. 1330 */ 1331 void 1332 knote(struct klist *list, long hint) 1333 { 1334 struct kqueue *kq; 1335 struct knote *kn; 1336 struct knote *kntmp; 1337 1338 lwkt_getpooltoken(list); 1339 restart: 1340 SLIST_FOREACH(kn, list, kn_next) { 1341 kq = kn->kn_kq; 1342 lwkt_getpooltoken(kq); 1343 1344 /* temporary verification hack */ 1345 SLIST_FOREACH(kntmp, list, kn_next) { 1346 if (kn == kntmp) 1347 break; 1348 } 1349 if (kn != kntmp || kn->kn_kq != kq) { 1350 lwkt_relpooltoken(kq); 1351 goto restart; 1352 } 1353 1354 if (kn->kn_status & KN_PROCESSING) { 1355 /* 1356 * Someone else is processing the knote, ask the 1357 * other thread to reprocess it and don't mess 1358 * with it otherwise. 1359 */ 1360 if (hint == 0) { 1361 kn->kn_status |= KN_REPROCESS; 1362 lwkt_relpooltoken(kq); 1363 continue; 1364 } 1365 1366 /* 1367 * If the hint is non-zero we have to wait or risk 1368 * losing the state the caller is trying to update. 1369 * 1370 * XXX This is a real problem, certain process 1371 * and signal filters will bump kn_data for 1372 * already-processed notes more than once if 1373 * we restart the list scan. FIXME. 1374 */ 1375 kn->kn_status |= KN_WAITING | KN_REPROCESS; 1376 tsleep(kn, 0, "knotec", hz); 1377 lwkt_relpooltoken(kq); 1378 goto restart; 1379 } 1380 1381 /* 1382 * Become the reprocessing master ourselves. 1383 * 1384 * If hint is non-zer running the event is mandatory 1385 * when not deleting so do it whether reprocessing is 1386 * set or not. 1387 */ 1388 kn->kn_status |= KN_PROCESSING; 1389 if ((kn->kn_status & KN_DELETING) == 0) { 1390 if (filter_event(kn, hint)) 1391 KNOTE_ACTIVATE(kn); 1392 } 1393 if (knote_release(kn)) { 1394 lwkt_relpooltoken(kq); 1395 goto restart; 1396 } 1397 lwkt_relpooltoken(kq); 1398 } 1399 lwkt_relpooltoken(list); 1400 } 1401 1402 /* 1403 * Insert knote at head of klist. 1404 * 1405 * This function may only be called via a filter function and thus 1406 * kq_token should already be held and marked for processing. 1407 */ 1408 void 1409 knote_insert(struct klist *klist, struct knote *kn) 1410 { 1411 lwkt_getpooltoken(klist); 1412 KKASSERT(kn->kn_status & KN_PROCESSING); 1413 SLIST_INSERT_HEAD(klist, kn, kn_next); 1414 lwkt_relpooltoken(klist); 1415 } 1416 1417 /* 1418 * Remove knote from a klist 1419 * 1420 * This function may only be called via a filter function and thus 1421 * kq_token should already be held and marked for processing. 1422 */ 1423 void 1424 knote_remove(struct klist *klist, struct knote *kn) 1425 { 1426 lwkt_getpooltoken(klist); 1427 KKASSERT(kn->kn_status & KN_PROCESSING); 1428 SLIST_REMOVE(klist, kn, knote, kn_next); 1429 lwkt_relpooltoken(klist); 1430 } 1431 1432 #if 0 1433 /* 1434 * Remove all knotes from a specified klist 1435 * 1436 * Only called from aio. 1437 */ 1438 void 1439 knote_empty(struct klist *list) 1440 { 1441 struct knote *kn; 1442 1443 lwkt_gettoken(&kq_token); 1444 while ((kn = SLIST_FIRST(list)) != NULL) { 1445 if (knote_acquire(kn)) 1446 knote_detach_and_drop(kn); 1447 } 1448 lwkt_reltoken(&kq_token); 1449 } 1450 #endif 1451 1452 void 1453 knote_assume_knotes(struct kqinfo *src, struct kqinfo *dst, 1454 struct filterops *ops, void *hook) 1455 { 1456 struct kqueue *kq; 1457 struct knote *kn; 1458 1459 lwkt_getpooltoken(&src->ki_note); 1460 lwkt_getpooltoken(&dst->ki_note); 1461 while ((kn = SLIST_FIRST(&src->ki_note)) != NULL) { 1462 kq = kn->kn_kq; 1463 lwkt_getpooltoken(kq); 1464 if (SLIST_FIRST(&src->ki_note) != kn || kn->kn_kq != kq) { 1465 lwkt_relpooltoken(kq); 1466 continue; 1467 } 1468 if (knote_acquire(kn)) { 1469 knote_remove(&src->ki_note, kn); 1470 kn->kn_fop = ops; 1471 kn->kn_hook = hook; 1472 knote_insert(&dst->ki_note, kn); 1473 knote_release(kn); 1474 /* kn may be invalid now */ 1475 } 1476 lwkt_relpooltoken(kq); 1477 } 1478 lwkt_relpooltoken(&dst->ki_note); 1479 lwkt_relpooltoken(&src->ki_note); 1480 } 1481 1482 /* 1483 * Remove all knotes referencing a specified fd 1484 */ 1485 void 1486 knote_fdclose(struct file *fp, struct filedesc *fdp, int fd) 1487 { 1488 struct kqueue *kq; 1489 struct knote *kn; 1490 struct knote *kntmp; 1491 1492 lwkt_getpooltoken(&fp->f_klist); 1493 restart: 1494 SLIST_FOREACH(kn, &fp->f_klist, kn_link) { 1495 if (kn->kn_kq->kq_fdp == fdp && kn->kn_id == fd) { 1496 kq = kn->kn_kq; 1497 lwkt_getpooltoken(kq); 1498 1499 /* temporary verification hack */ 1500 SLIST_FOREACH(kntmp, &fp->f_klist, kn_link) { 1501 if (kn == kntmp) 1502 break; 1503 } 1504 if (kn != kntmp || kn->kn_kq->kq_fdp != fdp || 1505 kn->kn_id != fd || kn->kn_kq != kq) { 1506 lwkt_relpooltoken(kq); 1507 goto restart; 1508 } 1509 if (knote_acquire(kn)) 1510 knote_detach_and_drop(kn); 1511 lwkt_relpooltoken(kq); 1512 goto restart; 1513 } 1514 } 1515 lwkt_relpooltoken(&fp->f_klist); 1516 } 1517 1518 /* 1519 * Low level attach function. 1520 * 1521 * The knote should already be marked for processing. 1522 * Caller must hold the related kq token. 1523 */ 1524 static void 1525 knote_attach(struct knote *kn) 1526 { 1527 struct klist *list; 1528 struct kqueue *kq = kn->kn_kq; 1529 1530 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1531 KKASSERT(kn->kn_fp); 1532 list = &kn->kn_fp->f_klist; 1533 } else { 1534 if (kq->kq_knhashmask == 0) 1535 kq->kq_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1536 &kq->kq_knhashmask); 1537 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1538 } 1539 lwkt_getpooltoken(list); 1540 SLIST_INSERT_HEAD(list, kn, kn_link); 1541 TAILQ_INSERT_HEAD(&kq->kq_knlist, kn, kn_kqlink); 1542 lwkt_relpooltoken(list); 1543 } 1544 1545 /* 1546 * Low level drop function. 1547 * 1548 * The knote should already be marked for processing. 1549 * Caller must hold the related kq token. 1550 */ 1551 static void 1552 knote_drop(struct knote *kn) 1553 { 1554 struct kqueue *kq; 1555 struct klist *list; 1556 1557 kq = kn->kn_kq; 1558 1559 if (kn->kn_fop->f_flags & FILTEROP_ISFD) 1560 list = &kn->kn_fp->f_klist; 1561 else 1562 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1563 1564 lwkt_getpooltoken(list); 1565 SLIST_REMOVE(list, kn, knote, kn_link); 1566 TAILQ_REMOVE(&kq->kq_knlist, kn, kn_kqlink); 1567 if (kn->kn_status & KN_QUEUED) 1568 knote_dequeue(kn); 1569 if (kn->kn_fop->f_flags & FILTEROP_ISFD) { 1570 fdrop(kn->kn_fp); 1571 kn->kn_fp = NULL; 1572 } 1573 knote_free(kn); 1574 lwkt_relpooltoken(list); 1575 } 1576 1577 /* 1578 * Low level enqueue function. 1579 * 1580 * The knote should already be marked for processing. 1581 * Caller must be holding the kq token 1582 */ 1583 static void 1584 knote_enqueue(struct knote *kn) 1585 { 1586 struct kqueue *kq = kn->kn_kq; 1587 1588 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1589 TAILQ_INSERT_TAIL(&kq->kq_knpend, kn, kn_tqe); 1590 kn->kn_status |= KN_QUEUED; 1591 ++kq->kq_count; 1592 1593 /* 1594 * Send SIGIO on request (typically set up as a mailbox signal) 1595 */ 1596 if (kq->kq_sigio && (kq->kq_state & KQ_ASYNC) && kq->kq_count == 1) 1597 pgsigio(kq->kq_sigio, SIGIO, 0); 1598 1599 kqueue_wakeup(kq); 1600 } 1601 1602 /* 1603 * Low level dequeue function. 1604 * 1605 * The knote should already be marked for processing. 1606 * Caller must be holding the kq token 1607 */ 1608 static void 1609 knote_dequeue(struct knote *kn) 1610 { 1611 struct kqueue *kq = kn->kn_kq; 1612 1613 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1614 TAILQ_REMOVE(&kq->kq_knpend, kn, kn_tqe); 1615 kn->kn_status &= ~KN_QUEUED; 1616 kq->kq_count--; 1617 } 1618 1619 static struct knote * 1620 knote_alloc(void) 1621 { 1622 return kmalloc(sizeof(struct knote), M_KQUEUE, M_WAITOK); 1623 } 1624 1625 static void 1626 knote_free(struct knote *kn) 1627 { 1628 kfree(kn, M_KQUEUE); 1629 } 1630