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 if (kn->kn_status & KN_DETACHED) 338 return; 339 340 p = kn->kn_ptr.p_proc; 341 knlist_remove(&p->p_klist, kn, 0); 342 kn->kn_ptr.p_proc = NULL; 343 } 344 345 /* XXX - move to kern_proc.c? */ 346 static int 347 filt_proc(struct knote *kn, long hint) 348 { 349 struct proc *p = kn->kn_ptr.p_proc; 350 u_int event; 351 352 /* 353 * mask off extra data 354 */ 355 event = (u_int)hint & NOTE_PCTRLMASK; 356 357 /* 358 * if the user is interested in this event, record it. 359 */ 360 if (kn->kn_sfflags & event) 361 kn->kn_fflags |= event; 362 363 /* 364 * process is gone, so flag the event as finished. 365 */ 366 if (event == NOTE_EXIT) { 367 if (!(kn->kn_status & KN_DETACHED)) 368 knlist_remove_inevent(&p->p_klist, kn); 369 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 370 kn->kn_ptr.p_proc = NULL; 371 return (1); 372 } 373 374 /* 375 * process forked, and user wants to track the new process, 376 * so attach a new knote to it, and immediately report an 377 * event with the parent's pid. 378 */ 379 if ((event == NOTE_FORK) && (kn->kn_sfflags & NOTE_TRACK)) { 380 struct kevent kev; 381 int error; 382 383 /* 384 * register knote with new process. 385 */ 386 kev.ident = hint & NOTE_PDATAMASK; /* pid */ 387 kev.filter = kn->kn_filter; 388 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 389 kev.fflags = kn->kn_sfflags; 390 kev.data = kn->kn_id; /* parent */ 391 kev.udata = kn->kn_kevent.udata; /* preserve udata */ 392 error = kqueue_register(kn->kn_kq, &kev, NULL, 0); 393 if (error) 394 kn->kn_fflags |= NOTE_TRACKERR; 395 } 396 397 return (kn->kn_fflags != 0); 398 } 399 400 static int 401 timertoticks(intptr_t data) 402 { 403 struct timeval tv; 404 int tticks; 405 406 tv.tv_sec = data / 1000; 407 tv.tv_usec = (data % 1000) * 1000; 408 tticks = tvtohz(&tv); 409 410 return tticks; 411 } 412 413 /* XXX - move to kern_timeout.c? */ 414 static void 415 filt_timerexpire(void *knx) 416 { 417 struct knote *kn = knx; 418 struct callout *calloutp; 419 420 kn->kn_data++; 421 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 422 423 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 424 calloutp = (struct callout *)kn->kn_hook; 425 callout_reset(calloutp, timertoticks(kn->kn_sdata), 426 filt_timerexpire, kn); 427 } 428 } 429 430 /* 431 * data contains amount of time to sleep, in milliseconds 432 */ 433 /* XXX - move to kern_timeout.c? */ 434 static int 435 filt_timerattach(struct knote *kn) 436 { 437 struct callout *calloutp; 438 439 atomic_add_int(&kq_ncallouts, 1); 440 441 if (kq_ncallouts >= kq_calloutmax) { 442 atomic_add_int(&kq_ncallouts, -1); 443 return (ENOMEM); 444 } 445 446 kn->kn_flags |= EV_CLEAR; /* automatically set */ 447 MALLOC(calloutp, struct callout *, sizeof(*calloutp), 448 M_KQUEUE, M_WAITOK); 449 callout_init(calloutp, 1); 450 kn->kn_hook = calloutp; 451 callout_reset(calloutp, timertoticks(kn->kn_sdata), filt_timerexpire, 452 kn); 453 454 return (0); 455 } 456 457 /* XXX - move to kern_timeout.c? */ 458 static void 459 filt_timerdetach(struct knote *kn) 460 { 461 struct callout *calloutp; 462 463 calloutp = (struct callout *)kn->kn_hook; 464 callout_drain(calloutp); 465 FREE(calloutp, M_KQUEUE); 466 atomic_add_int(&kq_ncallouts, -1); 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(fdp); 502 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 503 FILEDESC_UNLOCK(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 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 FILEDESC_UNLOCK(fdp); 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 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->kq_state |= KQ_SLEEP; 1110 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, 1111 "kqread", timeout); 1112 } 1113 if (error == 0) 1114 goto retry; 1115 /* don't restart after signals... */ 1116 if (error == ERESTART) 1117 error = EINTR; 1118 else if (error == EWOULDBLOCK) 1119 error = 0; 1120 goto done; 1121 } 1122 1123 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1124 while (count) { 1125 KQ_OWNED(kq); 1126 kn = TAILQ_FIRST(&kq->kq_head); 1127 1128 if ((kn->kn_status == KN_MARKER && kn != marker) || 1129 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1130 kq->kq_state |= KQ_FLUXWAIT; 1131 error = msleep(kq, &kq->kq_lock, PSOCK, 1132 "kqflxwt", 0); 1133 continue; 1134 } 1135 1136 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1137 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1138 kn->kn_status &= ~KN_QUEUED; 1139 kq->kq_count--; 1140 continue; 1141 } 1142 if (kn == marker) { 1143 KQ_FLUX_WAKEUP(kq); 1144 if (count == maxevents) 1145 goto retry; 1146 goto done; 1147 } 1148 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1149 ("KN_INFLUX set when not suppose to be")); 1150 1151 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1152 kn->kn_status &= ~KN_QUEUED; 1153 kn->kn_status |= KN_INFLUX; 1154 kq->kq_count--; 1155 KQ_UNLOCK(kq); 1156 /* 1157 * We don't need to lock the list since we've marked 1158 * it _INFLUX. 1159 */ 1160 *kevp = kn->kn_kevent; 1161 kn->kn_fop->f_detach(kn); 1162 knote_drop(kn, td); 1163 KQ_LOCK(kq); 1164 kn = NULL; 1165 } else { 1166 kn->kn_status |= KN_INFLUX; 1167 KQ_UNLOCK(kq); 1168 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1169 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1170 KN_LIST_LOCK(kn); 1171 if (kn->kn_fop->f_event(kn, 0) == 0) { 1172 KN_LIST_UNLOCK(kn); 1173 KQ_LOCK(kq); 1174 kn->kn_status &= 1175 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1176 kq->kq_count--; 1177 continue; 1178 } 1179 *kevp = kn->kn_kevent; 1180 KQ_LOCK(kq); 1181 if (kn->kn_flags & EV_CLEAR) { 1182 kn->kn_data = 0; 1183 kn->kn_fflags = 0; 1184 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1185 kq->kq_count--; 1186 } else 1187 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1188 KN_LIST_UNLOCK(kn); 1189 kn->kn_status &= ~(KN_INFLUX); 1190 } 1191 1192 /* we are returning a copy to the user */ 1193 kevp++; 1194 nkev++; 1195 count--; 1196 1197 if (nkev == KQ_NEVENTS) { 1198 KQ_UNLOCK_FLUX(kq); 1199 error = copyout(keva, ulistp, sizeof *keva * nkev); 1200 ulistp += nkev; 1201 nkev = 0; 1202 kevp = keva; 1203 KQ_LOCK(kq); 1204 if (error) 1205 break; 1206 } 1207 } 1208 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1209 done: 1210 KQ_OWNED(kq); 1211 KQ_UNLOCK_FLUX(kq); 1212 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1213 knote_free(marker); 1214 done_nl: 1215 KQ_NOTOWNED(kq); 1216 if (nkev != 0) 1217 error = copyout(keva, ulistp, sizeof *keva * nkev); 1218 td->td_retval[0] = maxevents - count; 1219 return (error); 1220 } 1221 1222 /* 1223 * XXX 1224 * This could be expanded to call kqueue_scan, if desired. 1225 */ 1226 /*ARGSUSED*/ 1227 static int 1228 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1229 int flags, struct thread *td) 1230 { 1231 return (ENXIO); 1232 } 1233 1234 /*ARGSUSED*/ 1235 static int 1236 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1237 int flags, struct thread *td) 1238 { 1239 return (ENXIO); 1240 } 1241 1242 /*ARGSUSED*/ 1243 static int 1244 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1245 struct ucred *active_cred, struct thread *td) 1246 { 1247 /* 1248 * Enabling sigio causes two major problems: 1249 * 1) infinite recursion: 1250 * Synopsys: kevent is being used to track signals and have FIOASYNC 1251 * set. On receipt of a signal this will cause a kqueue to recurse 1252 * into itself over and over. Sending the sigio causes the kqueue 1253 * to become ready, which in turn posts sigio again, forever. 1254 * Solution: this can be solved by setting a flag in the kqueue that 1255 * we have a SIGIO in progress. 1256 * 2) locking problems: 1257 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1258 * us above the proc and pgrp locks. 1259 * Solution: Post a signal using an async mechanism, being sure to 1260 * record a generation count in the delivery so that we do not deliver 1261 * a signal to the wrong process. 1262 * 1263 * Note, these two mechanisms are somewhat mutually exclusive! 1264 */ 1265 #if 0 1266 struct kqueue *kq; 1267 1268 kq = fp->f_data; 1269 switch (cmd) { 1270 case FIOASYNC: 1271 if (*(int *)data) { 1272 kq->kq_state |= KQ_ASYNC; 1273 } else { 1274 kq->kq_state &= ~KQ_ASYNC; 1275 } 1276 return (0); 1277 1278 case FIOSETOWN: 1279 return (fsetown(*(int *)data, &kq->kq_sigio)); 1280 1281 case FIOGETOWN: 1282 *(int *)data = fgetown(&kq->kq_sigio); 1283 return (0); 1284 } 1285 #endif 1286 1287 return (ENOTTY); 1288 } 1289 1290 /*ARGSUSED*/ 1291 static int 1292 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1293 struct thread *td) 1294 { 1295 struct kqueue *kq; 1296 int revents = 0; 1297 int error; 1298 1299 if ((error = kqueue_aquire(fp, &kq))) 1300 return POLLERR; 1301 1302 KQ_LOCK(kq); 1303 if (events & (POLLIN | POLLRDNORM)) { 1304 if (kq->kq_count) { 1305 revents |= events & (POLLIN | POLLRDNORM); 1306 } else { 1307 selrecord(td, &kq->kq_sel); 1308 kq->kq_state |= KQ_SEL; 1309 } 1310 } 1311 kqueue_release(kq, 1); 1312 KQ_UNLOCK(kq); 1313 return (revents); 1314 } 1315 1316 /*ARGSUSED*/ 1317 static int 1318 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1319 struct thread *td) 1320 { 1321 1322 return (ENXIO); 1323 } 1324 1325 /*ARGSUSED*/ 1326 static int 1327 kqueue_close(struct file *fp, struct thread *td) 1328 { 1329 struct kqueue *kq = fp->f_data; 1330 struct filedesc *fdp; 1331 struct knote *kn; 1332 int i; 1333 int error; 1334 1335 GIANT_REQUIRED; 1336 1337 if ((error = kqueue_aquire(fp, &kq))) 1338 return error; 1339 1340 KQ_LOCK(kq); 1341 1342 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1343 ("kqueue already closing")); 1344 kq->kq_state |= KQ_CLOSING; 1345 if (kq->kq_refcnt > 1) 1346 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1347 1348 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1349 fdp = kq->kq_fdp; 1350 1351 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1352 ("kqueue's knlist not empty")); 1353 1354 for (i = 0; i < kq->kq_knlistsize; i++) { 1355 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1356 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1357 ("KN_INFLUX set when not suppose to be")); 1358 kn->kn_status |= KN_INFLUX; 1359 KQ_UNLOCK(kq); 1360 kn->kn_fop->f_detach(kn); 1361 knote_drop(kn, td); 1362 KQ_LOCK(kq); 1363 } 1364 } 1365 if (kq->kq_knhashmask != 0) { 1366 for (i = 0; i <= kq->kq_knhashmask; i++) { 1367 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1368 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1369 ("KN_INFLUX set when not suppose to be")); 1370 kn->kn_status |= KN_INFLUX; 1371 KQ_UNLOCK(kq); 1372 kn->kn_fop->f_detach(kn); 1373 knote_drop(kn, td); 1374 KQ_LOCK(kq); 1375 } 1376 } 1377 } 1378 1379 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1380 kq->kq_state |= KQ_TASKDRAIN; 1381 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1382 } 1383 1384 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1385 kq->kq_state &= ~KQ_SEL; 1386 selwakeuppri(&kq->kq_sel, PSOCK); 1387 } 1388 1389 KQ_UNLOCK(kq); 1390 1391 FILEDESC_LOCK(fdp); 1392 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); 1393 FILEDESC_UNLOCK(fdp); 1394 1395 knlist_destroy(&kq->kq_sel.si_note); 1396 mtx_destroy(&kq->kq_lock); 1397 kq->kq_fdp = NULL; 1398 1399 if (kq->kq_knhash != NULL) 1400 free(kq->kq_knhash, M_KQUEUE); 1401 if (kq->kq_knlist != NULL) 1402 free(kq->kq_knlist, M_KQUEUE); 1403 1404 funsetown(&kq->kq_sigio); 1405 free(kq, M_KQUEUE); 1406 fp->f_data = NULL; 1407 1408 return (0); 1409 } 1410 1411 static void 1412 kqueue_wakeup(struct kqueue *kq) 1413 { 1414 KQ_OWNED(kq); 1415 1416 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1417 kq->kq_state &= ~KQ_SLEEP; 1418 wakeup(kq); 1419 } 1420 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1421 kq->kq_state &= ~KQ_SEL; 1422 selwakeuppri(&kq->kq_sel, PSOCK); 1423 } 1424 if (!knlist_empty(&kq->kq_sel.si_note)) 1425 kqueue_schedtask(kq); 1426 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1427 pgsigio(&kq->kq_sigio, SIGIO, 0); 1428 } 1429 } 1430 1431 /* 1432 * Walk down a list of knotes, activating them if their event has triggered. 1433 * 1434 * There is a possibility to optimize in the case of one kq watching another. 1435 * Instead of scheduling a task to wake it up, you could pass enough state 1436 * down the chain to make up the parent kqueue. Make this code functional 1437 * first. 1438 */ 1439 void 1440 knote(struct knlist *list, long hint, int islocked) 1441 { 1442 struct kqueue *kq; 1443 struct knote *kn; 1444 1445 if (list == NULL) 1446 return; 1447 1448 mtx_assert(list->kl_lock, islocked ? MA_OWNED : MA_NOTOWNED); 1449 if (!islocked) 1450 mtx_lock(list->kl_lock); 1451 /* 1452 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1453 * the kqueue scheduling, but this will introduce four 1454 * lock/unlock's for each knote to test. If we do, continue to use 1455 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1456 * only safe if you want to remove the current item, which we are 1457 * not doing. 1458 */ 1459 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1460 kq = kn->kn_kq; 1461 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1462 KQ_LOCK(kq); 1463 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1464 kn->kn_status |= KN_HASKQLOCK; 1465 if (kn->kn_fop->f_event(kn, hint)) 1466 KNOTE_ACTIVATE(kn, 1); 1467 kn->kn_status &= ~KN_HASKQLOCK; 1468 } 1469 KQ_UNLOCK(kq); 1470 } 1471 kq = NULL; 1472 } 1473 if (!islocked) 1474 mtx_unlock(list->kl_lock); 1475 } 1476 1477 /* 1478 * add a knote to a knlist 1479 */ 1480 void 1481 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1482 { 1483 mtx_assert(knl->kl_lock, islocked ? MA_OWNED : MA_NOTOWNED); 1484 KQ_NOTOWNED(kn->kn_kq); 1485 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1486 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1487 if (!islocked) 1488 mtx_lock(knl->kl_lock); 1489 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1490 if (!islocked) 1491 mtx_unlock(knl->kl_lock); 1492 KQ_LOCK(kn->kn_kq); 1493 kn->kn_knlist = knl; 1494 kn->kn_status &= ~KN_DETACHED; 1495 KQ_UNLOCK(kn->kn_kq); 1496 } 1497 1498 static void 1499 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1500 { 1501 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1502 mtx_assert(knl->kl_lock, knlislocked ? MA_OWNED : MA_NOTOWNED); 1503 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1504 if (!kqislocked) 1505 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1506 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1507 if (!knlislocked) 1508 mtx_lock(knl->kl_lock); 1509 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1510 kn->kn_knlist = NULL; 1511 if (!knlislocked) 1512 mtx_unlock(knl->kl_lock); 1513 if (!kqislocked) 1514 KQ_LOCK(kn->kn_kq); 1515 kn->kn_status |= KN_DETACHED; 1516 if (!kqislocked) 1517 KQ_UNLOCK(kn->kn_kq); 1518 } 1519 1520 /* 1521 * remove all knotes from a specified klist 1522 */ 1523 void 1524 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1525 { 1526 1527 knlist_remove_kq(knl, kn, islocked, 0); 1528 } 1529 1530 /* 1531 * remove knote from a specified klist while in f_event handler. 1532 */ 1533 void 1534 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1535 { 1536 1537 knlist_remove_kq(knl, kn, 1, 1538 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1539 } 1540 1541 int 1542 knlist_empty(struct knlist *knl) 1543 { 1544 1545 mtx_assert(knl->kl_lock, MA_OWNED); 1546 return SLIST_EMPTY(&knl->kl_list); 1547 } 1548 1549 static struct mtx knlist_lock; 1550 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1551 MTX_DEF); 1552 1553 void 1554 knlist_init(struct knlist *knl, struct mtx *mtx) 1555 { 1556 1557 if (mtx == NULL) 1558 knl->kl_lock = &knlist_lock; 1559 else 1560 knl->kl_lock = mtx; 1561 1562 SLIST_INIT(&knl->kl_list); 1563 } 1564 1565 void 1566 knlist_destroy(struct knlist *knl) 1567 { 1568 1569 #ifdef INVARIANTS 1570 /* 1571 * if we run across this error, we need to find the offending 1572 * driver and have it call knlist_clear. 1573 */ 1574 if (!SLIST_EMPTY(&knl->kl_list)) 1575 printf("WARNING: destroying knlist w/ knotes on it!\n"); 1576 #endif 1577 1578 knl->kl_lock = NULL; 1579 SLIST_INIT(&knl->kl_list); 1580 } 1581 1582 /* 1583 * Even if we are locked, we may need to drop the lock to allow any influx 1584 * knotes time to "settle". 1585 */ 1586 void 1587 knlist_clear(struct knlist *knl, int islocked) 1588 { 1589 struct knote *kn; 1590 struct kqueue *kq; 1591 1592 if (islocked) 1593 mtx_assert(knl->kl_lock, MA_OWNED); 1594 else { 1595 mtx_assert(knl->kl_lock, MA_NOTOWNED); 1596 again: /* need to reaquire lock since we have dropped it */ 1597 mtx_lock(knl->kl_lock); 1598 } 1599 1600 SLIST_FOREACH(kn, &knl->kl_list, kn_selnext) { 1601 kq = kn->kn_kq; 1602 KQ_LOCK(kq); 1603 if ((kn->kn_status & KN_INFLUX) && 1604 (kn->kn_status & KN_DETACHED) != KN_DETACHED) { 1605 KQ_UNLOCK(kq); 1606 continue; 1607 } 1608 /* Make sure cleared knotes disappear soon */ 1609 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 1610 knlist_remove_kq(knl, kn, 1, 1); 1611 KQ_UNLOCK(kq); 1612 kq = NULL; 1613 } 1614 1615 if (!SLIST_EMPTY(&knl->kl_list)) { 1616 /* there are still KN_INFLUX remaining */ 1617 kn = SLIST_FIRST(&knl->kl_list); 1618 kq = kn->kn_kq; 1619 KQ_LOCK(kq); 1620 KASSERT(kn->kn_status & KN_INFLUX, 1621 ("knote removed w/o list lock")); 1622 mtx_unlock(knl->kl_lock); 1623 kq->kq_state |= KQ_FLUXWAIT; 1624 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 1625 kq = NULL; 1626 goto again; 1627 } 1628 1629 SLIST_INIT(&knl->kl_list); 1630 1631 if (islocked) 1632 mtx_assert(knl->kl_lock, MA_OWNED); 1633 else { 1634 mtx_unlock(knl->kl_lock); 1635 mtx_assert(knl->kl_lock, MA_NOTOWNED); 1636 } 1637 } 1638 1639 /* 1640 * remove all knotes referencing a specified fd 1641 * must be called with FILEDESC lock. This prevents a race where a new fd 1642 * comes along and occupies the entry and we attach a knote to the fd. 1643 */ 1644 void 1645 knote_fdclose(struct thread *td, int fd) 1646 { 1647 struct filedesc *fdp = td->td_proc->p_fd; 1648 struct kqueue *kq; 1649 struct knote *kn; 1650 int influx; 1651 1652 FILEDESC_LOCK_ASSERT(fdp, MA_OWNED); 1653 1654 /* 1655 * We shouldn't have to worry about new kevents appearing on fd 1656 * since filedesc is locked. 1657 */ 1658 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 1659 KQ_LOCK(kq); 1660 1661 again: 1662 influx = 0; 1663 while (kq->kq_knlistsize > fd && 1664 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 1665 if (kn->kn_status & KN_INFLUX) { 1666 /* someone else might be waiting on our knote */ 1667 if (influx) 1668 wakeup(kq); 1669 kq->kq_state |= KQ_FLUXWAIT; 1670 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 1671 goto again; 1672 } 1673 kn->kn_status |= KN_INFLUX; 1674 KQ_UNLOCK(kq); 1675 kn->kn_fop->f_detach(kn); 1676 knote_drop(kn, td); 1677 influx = 1; 1678 KQ_LOCK(kq); 1679 } 1680 KQ_UNLOCK_FLUX(kq); 1681 } 1682 } 1683 1684 static int 1685 knote_attach(struct knote *kn, struct kqueue *kq) 1686 { 1687 struct klist *list; 1688 1689 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 1690 KQ_OWNED(kq); 1691 1692 if (kn->kn_fop->f_isfd) { 1693 if (kn->kn_id >= kq->kq_knlistsize) 1694 return ENOMEM; 1695 list = &kq->kq_knlist[kn->kn_id]; 1696 } else { 1697 if (kq->kq_knhash == NULL) 1698 return ENOMEM; 1699 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1700 } 1701 1702 SLIST_INSERT_HEAD(list, kn, kn_link); 1703 1704 return 0; 1705 } 1706 1707 /* 1708 * knote must already have been detatched using the f_detach method. 1709 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 1710 * to prevent other removal. 1711 */ 1712 static void 1713 knote_drop(struct knote *kn, struct thread *td) 1714 { 1715 struct kqueue *kq; 1716 struct klist *list; 1717 1718 kq = kn->kn_kq; 1719 1720 KQ_NOTOWNED(kq); 1721 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 1722 ("knote_drop called without KN_INFLUX set in kn_status")); 1723 1724 KQ_LOCK(kq); 1725 if (kn->kn_fop->f_isfd) 1726 list = &kq->kq_knlist[kn->kn_id]; 1727 else 1728 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 1729 1730 SLIST_REMOVE(list, kn, knote, kn_link); 1731 if (kn->kn_status & KN_QUEUED) 1732 knote_dequeue(kn); 1733 KQ_UNLOCK_FLUX(kq); 1734 1735 if (kn->kn_fop->f_isfd) { 1736 fdrop(kn->kn_fp, td); 1737 kn->kn_fp = NULL; 1738 } 1739 kqueue_fo_release(kn->kn_kevent.filter); 1740 kn->kn_fop = NULL; 1741 knote_free(kn); 1742 } 1743 1744 static void 1745 knote_enqueue(struct knote *kn) 1746 { 1747 struct kqueue *kq = kn->kn_kq; 1748 1749 KQ_OWNED(kn->kn_kq); 1750 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 1751 1752 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1753 kn->kn_status |= KN_QUEUED; 1754 kq->kq_count++; 1755 kqueue_wakeup(kq); 1756 } 1757 1758 static void 1759 knote_dequeue(struct knote *kn) 1760 { 1761 struct kqueue *kq = kn->kn_kq; 1762 1763 KQ_OWNED(kn->kn_kq); 1764 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 1765 1766 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1767 kn->kn_status &= ~KN_QUEUED; 1768 kq->kq_count--; 1769 } 1770 1771 static void 1772 knote_init(void) 1773 { 1774 1775 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 1776 NULL, NULL, UMA_ALIGN_PTR, 0); 1777 } 1778 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL) 1779 1780 static struct knote * 1781 knote_alloc(int waitok) 1782 { 1783 return ((struct knote *)uma_zalloc(knote_zone, 1784 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 1785 } 1786 1787 static void 1788 knote_free(struct knote *kn) 1789 { 1790 if (kn != NULL) 1791 uma_zfree(knote_zone, kn); 1792 } 1793