1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 4 * Copyright (c) 2009 Apple, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/kernel.h> 37 #include <sys/lock.h> 38 #include <sys/mutex.h> 39 #include <sys/proc.h> 40 #include <sys/malloc.h> 41 #include <sys/unistd.h> 42 #include <sys/file.h> 43 #include <sys/filedesc.h> 44 #include <sys/filio.h> 45 #include <sys/fcntl.h> 46 #include <sys/kthread.h> 47 #include <sys/selinfo.h> 48 #include <sys/queue.h> 49 #include <sys/event.h> 50 #include <sys/eventvar.h> 51 #include <sys/poll.h> 52 #include <sys/protosw.h> 53 #include <sys/sigio.h> 54 #include <sys/signalvar.h> 55 #include <sys/socket.h> 56 #include <sys/socketvar.h> 57 #include <sys/stat.h> 58 #include <sys/sysctl.h> 59 #include <sys/sysproto.h> 60 #include <sys/syscallsubr.h> 61 #include <sys/taskqueue.h> 62 #include <sys/uio.h> 63 #ifdef KTRACE 64 #include <sys/ktrace.h> 65 #endif 66 67 #include <vm/uma.h> 68 69 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 70 71 /* 72 * This lock is used if multiple kq locks are required. This possibly 73 * should be made into a per proc lock. 74 */ 75 static struct mtx kq_global; 76 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 77 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 78 if (!haslck) \ 79 mtx_lock(lck); \ 80 haslck = 1; \ 81 } while (0) 82 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 83 if (haslck) \ 84 mtx_unlock(lck); \ 85 haslck = 0; \ 86 } while (0) 87 88 TASKQUEUE_DEFINE_THREAD(kqueue); 89 90 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 91 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 92 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 93 struct thread *td, int waitok); 94 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 95 static void kqueue_release(struct kqueue *kq, int locked); 96 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 97 uintptr_t ident, int waitok); 98 static void kqueue_task(void *arg, int pending); 99 static int kqueue_scan(struct kqueue *kq, int maxevents, 100 struct kevent_copyops *k_ops, 101 const struct timespec *timeout, 102 struct kevent *keva, struct thread *td); 103 static void kqueue_wakeup(struct kqueue *kq); 104 static struct filterops *kqueue_fo_find(int filt); 105 static void kqueue_fo_release(int filt); 106 107 static fo_rdwr_t kqueue_read; 108 static fo_rdwr_t kqueue_write; 109 static fo_truncate_t kqueue_truncate; 110 static fo_ioctl_t kqueue_ioctl; 111 static fo_poll_t kqueue_poll; 112 static fo_kqfilter_t kqueue_kqfilter; 113 static fo_stat_t kqueue_stat; 114 static fo_close_t kqueue_close; 115 116 static struct fileops kqueueops = { 117 .fo_read = kqueue_read, 118 .fo_write = kqueue_write, 119 .fo_truncate = kqueue_truncate, 120 .fo_ioctl = kqueue_ioctl, 121 .fo_poll = kqueue_poll, 122 .fo_kqfilter = kqueue_kqfilter, 123 .fo_stat = kqueue_stat, 124 .fo_close = kqueue_close, 125 }; 126 127 static int knote_attach(struct knote *kn, struct kqueue *kq); 128 static void knote_drop(struct knote *kn, struct thread *td); 129 static void knote_enqueue(struct knote *kn); 130 static void knote_dequeue(struct knote *kn); 131 static void knote_init(void); 132 static struct knote *knote_alloc(int waitok); 133 static void knote_free(struct knote *kn); 134 135 static void filt_kqdetach(struct knote *kn); 136 static int filt_kqueue(struct knote *kn, long hint); 137 static int filt_procattach(struct knote *kn); 138 static void filt_procdetach(struct knote *kn); 139 static int filt_proc(struct knote *kn, long hint); 140 static int filt_fileattach(struct knote *kn); 141 static void filt_timerexpire(void *knx); 142 static int filt_timerattach(struct knote *kn); 143 static void filt_timerdetach(struct knote *kn); 144 static int filt_timer(struct knote *kn, long hint); 145 static int filt_userattach(struct knote *kn); 146 static void filt_userdetach(struct knote *kn); 147 static int filt_user(struct knote *kn, long hint); 148 static void filt_usertouch(struct knote *kn, struct kevent *kev, 149 u_long type); 150 151 static struct filterops file_filtops = { 152 .f_isfd = 1, 153 .f_attach = filt_fileattach, 154 }; 155 static struct filterops kqread_filtops = { 156 .f_isfd = 1, 157 .f_detach = filt_kqdetach, 158 .f_event = filt_kqueue, 159 }; 160 /* XXX - move to kern_proc.c? */ 161 static struct filterops proc_filtops = { 162 .f_isfd = 0, 163 .f_attach = filt_procattach, 164 .f_detach = filt_procdetach, 165 .f_event = filt_proc, 166 }; 167 static struct filterops timer_filtops = { 168 .f_isfd = 0, 169 .f_attach = filt_timerattach, 170 .f_detach = filt_timerdetach, 171 .f_event = filt_timer, 172 }; 173 static struct filterops user_filtops = { 174 .f_attach = filt_userattach, 175 .f_detach = filt_userdetach, 176 .f_event = filt_user, 177 .f_touch = filt_usertouch, 178 }; 179 180 static uma_zone_t knote_zone; 181 static int kq_ncallouts = 0; 182 static int kq_calloutmax = (4 * 1024); 183 SYSCTL_INT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 184 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 185 186 /* XXX - ensure not KN_INFLUX?? */ 187 #define KNOTE_ACTIVATE(kn, islock) do { \ 188 if ((islock)) \ 189 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 190 else \ 191 KQ_LOCK((kn)->kn_kq); \ 192 (kn)->kn_status |= KN_ACTIVE; \ 193 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 194 knote_enqueue((kn)); \ 195 if (!(islock)) \ 196 KQ_UNLOCK((kn)->kn_kq); \ 197 } while(0) 198 #define KQ_LOCK(kq) do { \ 199 mtx_lock(&(kq)->kq_lock); \ 200 } while (0) 201 #define KQ_FLUX_WAKEUP(kq) do { \ 202 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 203 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 204 wakeup((kq)); \ 205 } \ 206 } while (0) 207 #define KQ_UNLOCK_FLUX(kq) do { \ 208 KQ_FLUX_WAKEUP(kq); \ 209 mtx_unlock(&(kq)->kq_lock); \ 210 } while (0) 211 #define KQ_UNLOCK(kq) do { \ 212 mtx_unlock(&(kq)->kq_lock); \ 213 } while (0) 214 #define KQ_OWNED(kq) do { \ 215 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 216 } while (0) 217 #define KQ_NOTOWNED(kq) do { \ 218 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 219 } while (0) 220 #define KN_LIST_LOCK(kn) do { \ 221 if (kn->kn_knlist != NULL) \ 222 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 223 } while (0) 224 #define KN_LIST_UNLOCK(kn) do { \ 225 if (kn->kn_knlist != NULL) \ 226 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 227 } while (0) 228 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 229 if (islocked) \ 230 KNL_ASSERT_LOCKED(knl); \ 231 else \ 232 KNL_ASSERT_UNLOCKED(knl); \ 233 } while (0) 234 #ifdef INVARIANTS 235 #define KNL_ASSERT_LOCKED(knl) do { \ 236 knl->kl_assert_locked((knl)->kl_lockarg); \ 237 } while (0) 238 #define KNL_ASSERT_UNLOCKED(knl) do { \ 239 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 240 } while (0) 241 #else /* !INVARIANTS */ 242 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 243 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 244 #endif /* INVARIANTS */ 245 246 #define KN_HASHSIZE 64 /* XXX should be tunable */ 247 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 248 249 static int 250 filt_nullattach(struct knote *kn) 251 { 252 253 return (ENXIO); 254 }; 255 256 struct filterops null_filtops = { 257 .f_isfd = 0, 258 .f_attach = filt_nullattach, 259 }; 260 261 /* XXX - make SYSINIT to add these, and move into respective modules. */ 262 extern struct filterops sig_filtops; 263 extern struct filterops fs_filtops; 264 265 /* 266 * Table for for all system-defined filters. 267 */ 268 static struct mtx filterops_lock; 269 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 270 MTX_DEF); 271 static struct { 272 struct filterops *for_fop; 273 int for_refcnt; 274 } sysfilt_ops[EVFILT_SYSCOUNT] = { 275 { &file_filtops }, /* EVFILT_READ */ 276 { &file_filtops }, /* EVFILT_WRITE */ 277 { &null_filtops }, /* EVFILT_AIO */ 278 { &file_filtops }, /* EVFILT_VNODE */ 279 { &proc_filtops }, /* EVFILT_PROC */ 280 { &sig_filtops }, /* EVFILT_SIGNAL */ 281 { &timer_filtops }, /* EVFILT_TIMER */ 282 { &null_filtops }, /* former EVFILT_NETDEV */ 283 { &fs_filtops }, /* EVFILT_FS */ 284 { &null_filtops }, /* EVFILT_LIO */ 285 { &user_filtops }, /* EVFILT_USER */ 286 }; 287 288 /* 289 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 290 * method. 291 */ 292 static int 293 filt_fileattach(struct knote *kn) 294 { 295 296 return (fo_kqfilter(kn->kn_fp, kn)); 297 } 298 299 /*ARGSUSED*/ 300 static int 301 kqueue_kqfilter(struct file *fp, struct knote *kn) 302 { 303 struct kqueue *kq = kn->kn_fp->f_data; 304 305 if (kn->kn_filter != EVFILT_READ) 306 return (EINVAL); 307 308 kn->kn_status |= KN_KQUEUE; 309 kn->kn_fop = &kqread_filtops; 310 knlist_add(&kq->kq_sel.si_note, kn, 0); 311 312 return (0); 313 } 314 315 static void 316 filt_kqdetach(struct knote *kn) 317 { 318 struct kqueue *kq = kn->kn_fp->f_data; 319 320 knlist_remove(&kq->kq_sel.si_note, kn, 0); 321 } 322 323 /*ARGSUSED*/ 324 static int 325 filt_kqueue(struct knote *kn, long hint) 326 { 327 struct kqueue *kq = kn->kn_fp->f_data; 328 329 kn->kn_data = kq->kq_count; 330 return (kn->kn_data > 0); 331 } 332 333 /* XXX - move to kern_proc.c? */ 334 static int 335 filt_procattach(struct knote *kn) 336 { 337 struct proc *p; 338 int immediate; 339 int error; 340 341 immediate = 0; 342 p = pfind(kn->kn_id); 343 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 344 p = zpfind(kn->kn_id); 345 immediate = 1; 346 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 347 immediate = 1; 348 } 349 350 if (p == NULL) 351 return (ESRCH); 352 if ((error = p_cansee(curthread, p))) 353 return (error); 354 355 kn->kn_ptr.p_proc = p; 356 kn->kn_flags |= EV_CLEAR; /* automatically set */ 357 358 /* 359 * internal flag indicating registration done by kernel 360 */ 361 if (kn->kn_flags & EV_FLAG1) { 362 kn->kn_data = kn->kn_sdata; /* ppid */ 363 kn->kn_fflags = NOTE_CHILD; 364 kn->kn_flags &= ~EV_FLAG1; 365 } 366 367 if (immediate == 0) 368 knlist_add(&p->p_klist, kn, 1); 369 370 /* 371 * Immediately activate any exit notes if the target process is a 372 * zombie. This is necessary to handle the case where the target 373 * process, e.g. a child, dies before the kevent is registered. 374 */ 375 if (immediate && filt_proc(kn, NOTE_EXIT)) 376 KNOTE_ACTIVATE(kn, 0); 377 378 PROC_UNLOCK(p); 379 380 return (0); 381 } 382 383 /* 384 * The knote may be attached to a different process, which may exit, 385 * leaving nothing for the knote to be attached to. So when the process 386 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 387 * it will be deleted when read out. However, as part of the knote deletion, 388 * this routine is called, so a check is needed to avoid actually performing 389 * a detach, because the original process does not exist any more. 390 */ 391 /* XXX - move to kern_proc.c? */ 392 static void 393 filt_procdetach(struct knote *kn) 394 { 395 struct proc *p; 396 397 p = kn->kn_ptr.p_proc; 398 knlist_remove(&p->p_klist, kn, 0); 399 kn->kn_ptr.p_proc = NULL; 400 } 401 402 /* XXX - move to kern_proc.c? */ 403 static int 404 filt_proc(struct knote *kn, long hint) 405 { 406 struct proc *p = kn->kn_ptr.p_proc; 407 u_int event; 408 409 /* 410 * mask off extra data 411 */ 412 event = (u_int)hint & NOTE_PCTRLMASK; 413 414 /* 415 * if the user is interested in this event, record it. 416 */ 417 if (kn->kn_sfflags & event) 418 kn->kn_fflags |= event; 419 420 /* 421 * process is gone, so flag the event as finished. 422 */ 423 if (event == NOTE_EXIT) { 424 if (!(kn->kn_status & KN_DETACHED)) 425 knlist_remove_inevent(&p->p_klist, kn); 426 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 427 kn->kn_data = p->p_xstat; 428 kn->kn_ptr.p_proc = NULL; 429 return (1); 430 } 431 432 return (kn->kn_fflags != 0); 433 } 434 435 /* 436 * Called when the process forked. It mostly does the same as the 437 * knote(), activating all knotes registered to be activated when the 438 * process forked. Additionally, for each knote attached to the 439 * parent, check whether user wants to track the new process. If so 440 * attach a new knote to it, and immediately report an event with the 441 * child's pid. 442 */ 443 void 444 knote_fork(struct knlist *list, int pid) 445 { 446 struct kqueue *kq; 447 struct knote *kn; 448 struct kevent kev; 449 int error; 450 451 if (list == NULL) 452 return; 453 list->kl_lock(list->kl_lockarg); 454 455 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 456 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 457 continue; 458 kq = kn->kn_kq; 459 KQ_LOCK(kq); 460 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 461 KQ_UNLOCK(kq); 462 continue; 463 } 464 465 /* 466 * The same as knote(), activate the event. 467 */ 468 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 469 kn->kn_status |= KN_HASKQLOCK; 470 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid)) 471 KNOTE_ACTIVATE(kn, 1); 472 kn->kn_status &= ~KN_HASKQLOCK; 473 KQ_UNLOCK(kq); 474 continue; 475 } 476 477 /* 478 * The NOTE_TRACK case. In addition to the activation 479 * of the event, we need to register new event to 480 * track the child. Drop the locks in preparation for 481 * the call to kqueue_register(). 482 */ 483 kn->kn_status |= KN_INFLUX; 484 KQ_UNLOCK(kq); 485 list->kl_unlock(list->kl_lockarg); 486 487 /* 488 * Activate existing knote and register a knote with 489 * new process. 490 */ 491 kev.ident = pid; 492 kev.filter = kn->kn_filter; 493 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 494 kev.fflags = kn->kn_sfflags; 495 kev.data = kn->kn_id; /* parent */ 496 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 497 error = kqueue_register(kq, &kev, NULL, 0); 498 if (kn->kn_fop->f_event(kn, NOTE_FORK | pid)) 499 KNOTE_ACTIVATE(kn, 0); 500 if (error) 501 kn->kn_fflags |= NOTE_TRACKERR; 502 KQ_LOCK(kq); 503 kn->kn_status &= ~KN_INFLUX; 504 KQ_UNLOCK_FLUX(kq); 505 list->kl_lock(list->kl_lockarg); 506 } 507 list->kl_unlock(list->kl_lockarg); 508 } 509 510 static int 511 timertoticks(intptr_t data) 512 { 513 struct timeval tv; 514 int tticks; 515 516 tv.tv_sec = data / 1000; 517 tv.tv_usec = (data % 1000) * 1000; 518 tticks = tvtohz(&tv); 519 520 return tticks; 521 } 522 523 /* XXX - move to kern_timeout.c? */ 524 static void 525 filt_timerexpire(void *knx) 526 { 527 struct knote *kn = knx; 528 struct callout *calloutp; 529 530 kn->kn_data++; 531 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 532 533 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 534 calloutp = (struct callout *)kn->kn_hook; 535 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata), 536 filt_timerexpire, kn); 537 } 538 } 539 540 /* 541 * data contains amount of time to sleep, in milliseconds 542 */ 543 /* XXX - move to kern_timeout.c? */ 544 static int 545 filt_timerattach(struct knote *kn) 546 { 547 struct callout *calloutp; 548 549 atomic_add_int(&kq_ncallouts, 1); 550 551 if (kq_ncallouts >= kq_calloutmax) { 552 atomic_add_int(&kq_ncallouts, -1); 553 return (ENOMEM); 554 } 555 556 kn->kn_flags |= EV_CLEAR; /* automatically set */ 557 kn->kn_status &= ~KN_DETACHED; /* knlist_add usually sets it */ 558 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 559 callout_init(calloutp, CALLOUT_MPSAFE); 560 kn->kn_hook = calloutp; 561 callout_reset_curcpu(calloutp, timertoticks(kn->kn_sdata), 562 filt_timerexpire, kn); 563 564 return (0); 565 } 566 567 /* XXX - move to kern_timeout.c? */ 568 static void 569 filt_timerdetach(struct knote *kn) 570 { 571 struct callout *calloutp; 572 573 calloutp = (struct callout *)kn->kn_hook; 574 callout_drain(calloutp); 575 free(calloutp, M_KQUEUE); 576 atomic_add_int(&kq_ncallouts, -1); 577 kn->kn_status |= KN_DETACHED; /* knlist_remove usually clears it */ 578 } 579 580 /* XXX - move to kern_timeout.c? */ 581 static int 582 filt_timer(struct knote *kn, long hint) 583 { 584 585 return (kn->kn_data != 0); 586 } 587 588 static int 589 filt_userattach(struct knote *kn) 590 { 591 592 /* 593 * EVFILT_USER knotes are not attached to anything in the kernel. 594 */ 595 kn->kn_hook = NULL; 596 if (kn->kn_fflags & NOTE_TRIGGER) 597 kn->kn_hookid = 1; 598 else 599 kn->kn_hookid = 0; 600 return (0); 601 } 602 603 static void 604 filt_userdetach(__unused struct knote *kn) 605 { 606 607 /* 608 * EVFILT_USER knotes are not attached to anything in the kernel. 609 */ 610 } 611 612 static int 613 filt_user(struct knote *kn, __unused long hint) 614 { 615 616 return (kn->kn_hookid); 617 } 618 619 static void 620 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 621 { 622 u_int ffctrl; 623 624 switch (type) { 625 case EVENT_REGISTER: 626 if (kev->fflags & NOTE_TRIGGER) 627 kn->kn_hookid = 1; 628 629 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 630 kev->fflags &= NOTE_FFLAGSMASK; 631 switch (ffctrl) { 632 case NOTE_FFNOP: 633 break; 634 635 case NOTE_FFAND: 636 kn->kn_sfflags &= kev->fflags; 637 break; 638 639 case NOTE_FFOR: 640 kn->kn_sfflags |= kev->fflags; 641 break; 642 643 case NOTE_FFCOPY: 644 kn->kn_sfflags = kev->fflags; 645 break; 646 647 default: 648 /* XXX Return error? */ 649 break; 650 } 651 kn->kn_sdata = kev->data; 652 if (kev->flags & EV_CLEAR) { 653 kn->kn_hookid = 0; 654 kn->kn_data = 0; 655 kn->kn_fflags = 0; 656 } 657 break; 658 659 case EVENT_PROCESS: 660 *kev = kn->kn_kevent; 661 kev->fflags = kn->kn_sfflags; 662 kev->data = kn->kn_sdata; 663 if (kn->kn_flags & EV_CLEAR) { 664 kn->kn_hookid = 0; 665 kn->kn_data = 0; 666 kn->kn_fflags = 0; 667 } 668 break; 669 670 default: 671 panic("filt_usertouch() - invalid type (%ld)", type); 672 break; 673 } 674 } 675 676 int 677 kqueue(struct thread *td, struct kqueue_args *uap) 678 { 679 struct filedesc *fdp; 680 struct kqueue *kq; 681 struct file *fp; 682 int fd, error; 683 684 fdp = td->td_proc->p_fd; 685 error = falloc(td, &fp, &fd); 686 if (error) 687 goto done2; 688 689 /* An extra reference on `nfp' has been held for us by falloc(). */ 690 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 691 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 692 TAILQ_INIT(&kq->kq_head); 693 kq->kq_fdp = fdp; 694 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 695 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 696 697 FILEDESC_XLOCK(fdp); 698 SLIST_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 699 FILEDESC_XUNLOCK(fdp); 700 701 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 702 fdrop(fp, td); 703 704 td->td_retval[0] = fd; 705 done2: 706 return (error); 707 } 708 709 #ifndef _SYS_SYSPROTO_H_ 710 struct kevent_args { 711 int fd; 712 const struct kevent *changelist; 713 int nchanges; 714 struct kevent *eventlist; 715 int nevents; 716 const struct timespec *timeout; 717 }; 718 #endif 719 int 720 kevent(struct thread *td, struct kevent_args *uap) 721 { 722 struct timespec ts, *tsp; 723 struct kevent_copyops k_ops = { uap, 724 kevent_copyout, 725 kevent_copyin}; 726 int error; 727 #ifdef KTRACE 728 struct uio ktruio; 729 struct iovec ktriov; 730 struct uio *ktruioin = NULL; 731 struct uio *ktruioout = NULL; 732 #endif 733 734 if (uap->timeout != NULL) { 735 error = copyin(uap->timeout, &ts, sizeof(ts)); 736 if (error) 737 return (error); 738 tsp = &ts; 739 } else 740 tsp = NULL; 741 742 #ifdef KTRACE 743 if (KTRPOINT(td, KTR_GENIO)) { 744 ktriov.iov_base = uap->changelist; 745 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 746 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 747 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 748 .uio_td = td }; 749 ktruioin = cloneuio(&ktruio); 750 ktriov.iov_base = uap->eventlist; 751 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 752 ktruioout = cloneuio(&ktruio); 753 } 754 #endif 755 756 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 757 &k_ops, tsp); 758 759 #ifdef KTRACE 760 if (ktruioin != NULL) { 761 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 762 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 763 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 764 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 765 } 766 #endif 767 768 return (error); 769 } 770 771 /* 772 * Copy 'count' items into the destination list pointed to by uap->eventlist. 773 */ 774 static int 775 kevent_copyout(void *arg, struct kevent *kevp, int count) 776 { 777 struct kevent_args *uap; 778 int error; 779 780 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 781 uap = (struct kevent_args *)arg; 782 783 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 784 if (error == 0) 785 uap->eventlist += count; 786 return (error); 787 } 788 789 /* 790 * Copy 'count' items from the list pointed to by uap->changelist. 791 */ 792 static int 793 kevent_copyin(void *arg, struct kevent *kevp, int count) 794 { 795 struct kevent_args *uap; 796 int error; 797 798 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 799 uap = (struct kevent_args *)arg; 800 801 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 802 if (error == 0) 803 uap->changelist += count; 804 return (error); 805 } 806 807 int 808 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 809 struct kevent_copyops *k_ops, const struct timespec *timeout) 810 { 811 struct kevent keva[KQ_NEVENTS]; 812 struct kevent *kevp, *changes; 813 struct kqueue *kq; 814 struct file *fp; 815 int i, n, nerrors, error; 816 817 if ((error = fget(td, fd, &fp)) != 0) 818 return (error); 819 if ((error = kqueue_acquire(fp, &kq)) != 0) 820 goto done_norel; 821 822 nerrors = 0; 823 824 while (nchanges > 0) { 825 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 826 error = k_ops->k_copyin(k_ops->arg, keva, n); 827 if (error) 828 goto done; 829 changes = keva; 830 for (i = 0; i < n; i++) { 831 kevp = &changes[i]; 832 if (!kevp->filter) 833 continue; 834 kevp->flags &= ~EV_SYSFLAGS; 835 error = kqueue_register(kq, kevp, td, 1); 836 if (error || (kevp->flags & EV_RECEIPT)) { 837 if (nevents != 0) { 838 kevp->flags = EV_ERROR; 839 kevp->data = error; 840 (void) k_ops->k_copyout(k_ops->arg, 841 kevp, 1); 842 nevents--; 843 nerrors++; 844 } else { 845 goto done; 846 } 847 } 848 } 849 nchanges -= n; 850 } 851 if (nerrors) { 852 td->td_retval[0] = nerrors; 853 error = 0; 854 goto done; 855 } 856 857 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 858 done: 859 kqueue_release(kq, 0); 860 done_norel: 861 fdrop(fp, td); 862 return (error); 863 } 864 865 int 866 kqueue_add_filteropts(int filt, struct filterops *filtops) 867 { 868 int error; 869 870 error = 0; 871 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 872 printf( 873 "trying to add a filterop that is out of range: %d is beyond %d\n", 874 ~filt, EVFILT_SYSCOUNT); 875 return EINVAL; 876 } 877 mtx_lock(&filterops_lock); 878 if (sysfilt_ops[~filt].for_fop != &null_filtops && 879 sysfilt_ops[~filt].for_fop != NULL) 880 error = EEXIST; 881 else { 882 sysfilt_ops[~filt].for_fop = filtops; 883 sysfilt_ops[~filt].for_refcnt = 0; 884 } 885 mtx_unlock(&filterops_lock); 886 887 return (error); 888 } 889 890 int 891 kqueue_del_filteropts(int filt) 892 { 893 int error; 894 895 error = 0; 896 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 897 return EINVAL; 898 899 mtx_lock(&filterops_lock); 900 if (sysfilt_ops[~filt].for_fop == &null_filtops || 901 sysfilt_ops[~filt].for_fop == NULL) 902 error = EINVAL; 903 else if (sysfilt_ops[~filt].for_refcnt != 0) 904 error = EBUSY; 905 else { 906 sysfilt_ops[~filt].for_fop = &null_filtops; 907 sysfilt_ops[~filt].for_refcnt = 0; 908 } 909 mtx_unlock(&filterops_lock); 910 911 return error; 912 } 913 914 static struct filterops * 915 kqueue_fo_find(int filt) 916 { 917 918 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 919 return NULL; 920 921 mtx_lock(&filterops_lock); 922 sysfilt_ops[~filt].for_refcnt++; 923 if (sysfilt_ops[~filt].for_fop == NULL) 924 sysfilt_ops[~filt].for_fop = &null_filtops; 925 mtx_unlock(&filterops_lock); 926 927 return sysfilt_ops[~filt].for_fop; 928 } 929 930 static void 931 kqueue_fo_release(int filt) 932 { 933 934 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 935 return; 936 937 mtx_lock(&filterops_lock); 938 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 939 ("filter object refcount not valid on release")); 940 sysfilt_ops[~filt].for_refcnt--; 941 mtx_unlock(&filterops_lock); 942 } 943 944 /* 945 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 946 * influence if memory allocation should wait. Make sure it is 0 if you 947 * hold any mutexes. 948 */ 949 static int 950 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 951 { 952 struct filterops *fops; 953 struct file *fp; 954 struct knote *kn, *tkn; 955 int error, filt, event; 956 int haskqglobal; 957 958 fp = NULL; 959 kn = NULL; 960 error = 0; 961 haskqglobal = 0; 962 963 filt = kev->filter; 964 fops = kqueue_fo_find(filt); 965 if (fops == NULL) 966 return EINVAL; 967 968 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 969 970 findkn: 971 if (fops->f_isfd) { 972 KASSERT(td != NULL, ("td is NULL")); 973 error = fget(td, kev->ident, &fp); 974 if (error) 975 goto done; 976 977 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 978 kev->ident, 0) != 0) { 979 /* try again */ 980 fdrop(fp, td); 981 fp = NULL; 982 error = kqueue_expand(kq, fops, kev->ident, waitok); 983 if (error) 984 goto done; 985 goto findkn; 986 } 987 988 if (fp->f_type == DTYPE_KQUEUE) { 989 /* 990 * if we add some inteligence about what we are doing, 991 * we should be able to support events on ourselves. 992 * We need to know when we are doing this to prevent 993 * getting both the knlist lock and the kq lock since 994 * they are the same thing. 995 */ 996 if (fp->f_data == kq) { 997 error = EINVAL; 998 goto done; 999 } 1000 1001 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1002 } 1003 1004 KQ_LOCK(kq); 1005 if (kev->ident < kq->kq_knlistsize) { 1006 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1007 if (kev->filter == kn->kn_filter) 1008 break; 1009 } 1010 } else { 1011 if ((kev->flags & EV_ADD) == EV_ADD) 1012 kqueue_expand(kq, fops, kev->ident, waitok); 1013 1014 KQ_LOCK(kq); 1015 if (kq->kq_knhashmask != 0) { 1016 struct klist *list; 1017 1018 list = &kq->kq_knhash[ 1019 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1020 SLIST_FOREACH(kn, list, kn_link) 1021 if (kev->ident == kn->kn_id && 1022 kev->filter == kn->kn_filter) 1023 break; 1024 } 1025 } 1026 1027 /* knote is in the process of changing, wait for it to stablize. */ 1028 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1029 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1030 kq->kq_state |= KQ_FLUXWAIT; 1031 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1032 if (fp != NULL) { 1033 fdrop(fp, td); 1034 fp = NULL; 1035 } 1036 goto findkn; 1037 } 1038 1039 /* 1040 * kn now contains the matching knote, or NULL if no match 1041 */ 1042 if (kn == NULL) { 1043 if (kev->flags & EV_ADD) { 1044 kn = tkn; 1045 tkn = NULL; 1046 if (kn == NULL) { 1047 KQ_UNLOCK(kq); 1048 error = ENOMEM; 1049 goto done; 1050 } 1051 kn->kn_fp = fp; 1052 kn->kn_kq = kq; 1053 kn->kn_fop = fops; 1054 /* 1055 * apply reference counts to knote structure, and 1056 * do not release it at the end of this routine. 1057 */ 1058 fops = NULL; 1059 fp = NULL; 1060 1061 kn->kn_sfflags = kev->fflags; 1062 kn->kn_sdata = kev->data; 1063 kev->fflags = 0; 1064 kev->data = 0; 1065 kn->kn_kevent = *kev; 1066 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1067 EV_ENABLE | EV_DISABLE); 1068 kn->kn_status = KN_INFLUX|KN_DETACHED; 1069 1070 error = knote_attach(kn, kq); 1071 KQ_UNLOCK(kq); 1072 if (error != 0) { 1073 tkn = kn; 1074 goto done; 1075 } 1076 1077 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1078 knote_drop(kn, td); 1079 goto done; 1080 } 1081 KN_LIST_LOCK(kn); 1082 goto done_ev_add; 1083 } else { 1084 /* No matching knote and the EV_ADD flag is not set. */ 1085 KQ_UNLOCK(kq); 1086 error = ENOENT; 1087 goto done; 1088 } 1089 } 1090 1091 if (kev->flags & EV_DELETE) { 1092 kn->kn_status |= KN_INFLUX; 1093 KQ_UNLOCK(kq); 1094 if (!(kn->kn_status & KN_DETACHED)) 1095 kn->kn_fop->f_detach(kn); 1096 knote_drop(kn, td); 1097 goto done; 1098 } 1099 1100 /* 1101 * The user may change some filter values after the initial EV_ADD, 1102 * but doing so will not reset any filter which has already been 1103 * triggered. 1104 */ 1105 kn->kn_status |= KN_INFLUX; 1106 KQ_UNLOCK(kq); 1107 KN_LIST_LOCK(kn); 1108 kn->kn_kevent.udata = kev->udata; 1109 if (!fops->f_isfd && fops->f_touch != NULL) { 1110 fops->f_touch(kn, kev, EVENT_REGISTER); 1111 } else { 1112 kn->kn_sfflags = kev->fflags; 1113 kn->kn_sdata = kev->data; 1114 } 1115 1116 /* 1117 * We can get here with kn->kn_knlist == NULL. This can happen when 1118 * the initial attach event decides that the event is "completed" 1119 * already. i.e. filt_procattach is called on a zombie process. It 1120 * will call filt_proc which will remove it from the list, and NULL 1121 * kn_knlist. 1122 */ 1123 done_ev_add: 1124 event = kn->kn_fop->f_event(kn, 0); 1125 KQ_LOCK(kq); 1126 if (event) 1127 KNOTE_ACTIVATE(kn, 1); 1128 kn->kn_status &= ~KN_INFLUX; 1129 KN_LIST_UNLOCK(kn); 1130 1131 if ((kev->flags & EV_DISABLE) && 1132 ((kn->kn_status & KN_DISABLED) == 0)) { 1133 kn->kn_status |= KN_DISABLED; 1134 } 1135 1136 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1137 kn->kn_status &= ~KN_DISABLED; 1138 if ((kn->kn_status & KN_ACTIVE) && 1139 ((kn->kn_status & KN_QUEUED) == 0)) 1140 knote_enqueue(kn); 1141 } 1142 KQ_UNLOCK_FLUX(kq); 1143 1144 done: 1145 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1146 if (fp != NULL) 1147 fdrop(fp, td); 1148 if (tkn != NULL) 1149 knote_free(tkn); 1150 if (fops != NULL) 1151 kqueue_fo_release(filt); 1152 return (error); 1153 } 1154 1155 static int 1156 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1157 { 1158 int error; 1159 struct kqueue *kq; 1160 1161 error = 0; 1162 1163 kq = fp->f_data; 1164 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1165 return (EBADF); 1166 *kqp = kq; 1167 KQ_LOCK(kq); 1168 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1169 KQ_UNLOCK(kq); 1170 return (EBADF); 1171 } 1172 kq->kq_refcnt++; 1173 KQ_UNLOCK(kq); 1174 1175 return error; 1176 } 1177 1178 static void 1179 kqueue_release(struct kqueue *kq, int locked) 1180 { 1181 if (locked) 1182 KQ_OWNED(kq); 1183 else 1184 KQ_LOCK(kq); 1185 kq->kq_refcnt--; 1186 if (kq->kq_refcnt == 1) 1187 wakeup(&kq->kq_refcnt); 1188 if (!locked) 1189 KQ_UNLOCK(kq); 1190 } 1191 1192 static void 1193 kqueue_schedtask(struct kqueue *kq) 1194 { 1195 1196 KQ_OWNED(kq); 1197 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1198 ("scheduling kqueue task while draining")); 1199 1200 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1201 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1202 kq->kq_state |= KQ_TASKSCHED; 1203 } 1204 } 1205 1206 /* 1207 * Expand the kq to make sure we have storage for fops/ident pair. 1208 * 1209 * Return 0 on success (or no work necessary), return errno on failure. 1210 * 1211 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1212 * If kqueue_register is called from a non-fd context, there usually/should 1213 * be no locks held. 1214 */ 1215 static int 1216 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1217 int waitok) 1218 { 1219 struct klist *list, *tmp_knhash; 1220 u_long tmp_knhashmask; 1221 int size; 1222 int fd; 1223 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1224 1225 KQ_NOTOWNED(kq); 1226 1227 if (fops->f_isfd) { 1228 fd = ident; 1229 if (kq->kq_knlistsize <= fd) { 1230 size = kq->kq_knlistsize; 1231 while (size <= fd) 1232 size += KQEXTENT; 1233 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1234 if (list == NULL) 1235 return ENOMEM; 1236 KQ_LOCK(kq); 1237 if (kq->kq_knlistsize > fd) { 1238 free(list, M_KQUEUE); 1239 list = NULL; 1240 } else { 1241 if (kq->kq_knlist != NULL) { 1242 bcopy(kq->kq_knlist, list, 1243 kq->kq_knlistsize * sizeof(*list)); 1244 free(kq->kq_knlist, M_KQUEUE); 1245 kq->kq_knlist = NULL; 1246 } 1247 bzero((caddr_t)list + 1248 kq->kq_knlistsize * sizeof(*list), 1249 (size - kq->kq_knlistsize) * sizeof(*list)); 1250 kq->kq_knlistsize = size; 1251 kq->kq_knlist = list; 1252 } 1253 KQ_UNLOCK(kq); 1254 } 1255 } else { 1256 if (kq->kq_knhashmask == 0) { 1257 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1258 &tmp_knhashmask); 1259 if (tmp_knhash == NULL) 1260 return ENOMEM; 1261 KQ_LOCK(kq); 1262 if (kq->kq_knhashmask == 0) { 1263 kq->kq_knhash = tmp_knhash; 1264 kq->kq_knhashmask = tmp_knhashmask; 1265 } else { 1266 free(tmp_knhash, M_KQUEUE); 1267 } 1268 KQ_UNLOCK(kq); 1269 } 1270 } 1271 1272 KQ_NOTOWNED(kq); 1273 return 0; 1274 } 1275 1276 static void 1277 kqueue_task(void *arg, int pending) 1278 { 1279 struct kqueue *kq; 1280 int haskqglobal; 1281 1282 haskqglobal = 0; 1283 kq = arg; 1284 1285 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1286 KQ_LOCK(kq); 1287 1288 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1289 1290 kq->kq_state &= ~KQ_TASKSCHED; 1291 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1292 wakeup(&kq->kq_state); 1293 } 1294 KQ_UNLOCK(kq); 1295 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1296 } 1297 1298 /* 1299 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1300 * We treat KN_MARKER knotes as if they are INFLUX. 1301 */ 1302 static int 1303 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1304 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1305 { 1306 struct kevent *kevp; 1307 struct timeval atv, rtv, ttv; 1308 struct knote *kn, *marker; 1309 int count, timeout, nkev, error, influx; 1310 int haskqglobal, touch; 1311 1312 count = maxevents; 1313 nkev = 0; 1314 error = 0; 1315 haskqglobal = 0; 1316 1317 if (maxevents == 0) 1318 goto done_nl; 1319 1320 if (tsp != NULL) { 1321 TIMESPEC_TO_TIMEVAL(&atv, tsp); 1322 if (itimerfix(&atv)) { 1323 error = EINVAL; 1324 goto done_nl; 1325 } 1326 if (tsp->tv_sec == 0 && tsp->tv_nsec == 0) 1327 timeout = -1; 1328 else 1329 timeout = atv.tv_sec > 24 * 60 * 60 ? 1330 24 * 60 * 60 * hz : tvtohz(&atv); 1331 getmicrouptime(&rtv); 1332 timevaladd(&atv, &rtv); 1333 } else { 1334 atv.tv_sec = 0; 1335 atv.tv_usec = 0; 1336 timeout = 0; 1337 } 1338 marker = knote_alloc(1); 1339 if (marker == NULL) { 1340 error = ENOMEM; 1341 goto done_nl; 1342 } 1343 marker->kn_status = KN_MARKER; 1344 KQ_LOCK(kq); 1345 goto start; 1346 1347 retry: 1348 if (atv.tv_sec || atv.tv_usec) { 1349 getmicrouptime(&rtv); 1350 if (timevalcmp(&rtv, &atv, >=)) 1351 goto done; 1352 ttv = atv; 1353 timevalsub(&ttv, &rtv); 1354 timeout = ttv.tv_sec > 24 * 60 * 60 ? 1355 24 * 60 * 60 * hz : tvtohz(&ttv); 1356 } 1357 1358 start: 1359 kevp = keva; 1360 if (kq->kq_count == 0) { 1361 if (timeout < 0) { 1362 error = EWOULDBLOCK; 1363 } else { 1364 kq->kq_state |= KQ_SLEEP; 1365 error = msleep(kq, &kq->kq_lock, PSOCK | PCATCH, 1366 "kqread", timeout); 1367 } 1368 if (error == 0) 1369 goto retry; 1370 /* don't restart after signals... */ 1371 if (error == ERESTART) 1372 error = EINTR; 1373 else if (error == EWOULDBLOCK) 1374 error = 0; 1375 goto done; 1376 } 1377 1378 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1379 influx = 0; 1380 while (count) { 1381 KQ_OWNED(kq); 1382 kn = TAILQ_FIRST(&kq->kq_head); 1383 1384 if ((kn->kn_status == KN_MARKER && kn != marker) || 1385 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1386 if (influx) { 1387 influx = 0; 1388 KQ_FLUX_WAKEUP(kq); 1389 } 1390 kq->kq_state |= KQ_FLUXWAIT; 1391 error = msleep(kq, &kq->kq_lock, PSOCK, 1392 "kqflxwt", 0); 1393 continue; 1394 } 1395 1396 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1397 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1398 kn->kn_status &= ~KN_QUEUED; 1399 kq->kq_count--; 1400 continue; 1401 } 1402 if (kn == marker) { 1403 KQ_FLUX_WAKEUP(kq); 1404 if (count == maxevents) 1405 goto retry; 1406 goto done; 1407 } 1408 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1409 ("KN_INFLUX set when not suppose to be")); 1410 1411 if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1412 kn->kn_status &= ~KN_QUEUED; 1413 kn->kn_status |= KN_INFLUX; 1414 kq->kq_count--; 1415 KQ_UNLOCK(kq); 1416 /* 1417 * We don't need to lock the list since we've marked 1418 * it _INFLUX. 1419 */ 1420 *kevp = kn->kn_kevent; 1421 if (!(kn->kn_status & KN_DETACHED)) 1422 kn->kn_fop->f_detach(kn); 1423 knote_drop(kn, td); 1424 KQ_LOCK(kq); 1425 kn = NULL; 1426 } else { 1427 kn->kn_status |= KN_INFLUX; 1428 KQ_UNLOCK(kq); 1429 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1430 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1431 KN_LIST_LOCK(kn); 1432 if (kn->kn_fop->f_event(kn, 0) == 0) { 1433 KQ_LOCK(kq); 1434 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1435 kn->kn_status &= 1436 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1437 kq->kq_count--; 1438 KN_LIST_UNLOCK(kn); 1439 influx = 1; 1440 continue; 1441 } 1442 touch = (!kn->kn_fop->f_isfd && 1443 kn->kn_fop->f_touch != NULL); 1444 if (touch) 1445 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1446 else 1447 *kevp = kn->kn_kevent; 1448 KQ_LOCK(kq); 1449 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1450 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1451 /* 1452 * Manually clear knotes who weren't 1453 * 'touch'ed. 1454 */ 1455 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1456 kn->kn_data = 0; 1457 kn->kn_fflags = 0; 1458 } 1459 if (kn->kn_flags & EV_DISPATCH) 1460 kn->kn_status |= KN_DISABLED; 1461 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1462 kq->kq_count--; 1463 } else 1464 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1465 1466 kn->kn_status &= ~(KN_INFLUX); 1467 KN_LIST_UNLOCK(kn); 1468 influx = 1; 1469 } 1470 1471 /* we are returning a copy to the user */ 1472 kevp++; 1473 nkev++; 1474 count--; 1475 1476 if (nkev == KQ_NEVENTS) { 1477 influx = 0; 1478 KQ_UNLOCK_FLUX(kq); 1479 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1480 nkev = 0; 1481 kevp = keva; 1482 KQ_LOCK(kq); 1483 if (error) 1484 break; 1485 } 1486 } 1487 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1488 done: 1489 KQ_OWNED(kq); 1490 KQ_UNLOCK_FLUX(kq); 1491 knote_free(marker); 1492 done_nl: 1493 KQ_NOTOWNED(kq); 1494 if (nkev != 0) 1495 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1496 td->td_retval[0] = maxevents - count; 1497 return (error); 1498 } 1499 1500 /* 1501 * XXX 1502 * This could be expanded to call kqueue_scan, if desired. 1503 */ 1504 /*ARGSUSED*/ 1505 static int 1506 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1507 int flags, struct thread *td) 1508 { 1509 return (ENXIO); 1510 } 1511 1512 /*ARGSUSED*/ 1513 static int 1514 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1515 int flags, struct thread *td) 1516 { 1517 return (ENXIO); 1518 } 1519 1520 /*ARGSUSED*/ 1521 static int 1522 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1523 struct thread *td) 1524 { 1525 1526 return (EINVAL); 1527 } 1528 1529 /*ARGSUSED*/ 1530 static int 1531 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1532 struct ucred *active_cred, struct thread *td) 1533 { 1534 /* 1535 * Enabling sigio causes two major problems: 1536 * 1) infinite recursion: 1537 * Synopsys: kevent is being used to track signals and have FIOASYNC 1538 * set. On receipt of a signal this will cause a kqueue to recurse 1539 * into itself over and over. Sending the sigio causes the kqueue 1540 * to become ready, which in turn posts sigio again, forever. 1541 * Solution: this can be solved by setting a flag in the kqueue that 1542 * we have a SIGIO in progress. 1543 * 2) locking problems: 1544 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1545 * us above the proc and pgrp locks. 1546 * Solution: Post a signal using an async mechanism, being sure to 1547 * record a generation count in the delivery so that we do not deliver 1548 * a signal to the wrong process. 1549 * 1550 * Note, these two mechanisms are somewhat mutually exclusive! 1551 */ 1552 #if 0 1553 struct kqueue *kq; 1554 1555 kq = fp->f_data; 1556 switch (cmd) { 1557 case FIOASYNC: 1558 if (*(int *)data) { 1559 kq->kq_state |= KQ_ASYNC; 1560 } else { 1561 kq->kq_state &= ~KQ_ASYNC; 1562 } 1563 return (0); 1564 1565 case FIOSETOWN: 1566 return (fsetown(*(int *)data, &kq->kq_sigio)); 1567 1568 case FIOGETOWN: 1569 *(int *)data = fgetown(&kq->kq_sigio); 1570 return (0); 1571 } 1572 #endif 1573 1574 return (ENOTTY); 1575 } 1576 1577 /*ARGSUSED*/ 1578 static int 1579 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1580 struct thread *td) 1581 { 1582 struct kqueue *kq; 1583 int revents = 0; 1584 int error; 1585 1586 if ((error = kqueue_acquire(fp, &kq))) 1587 return POLLERR; 1588 1589 KQ_LOCK(kq); 1590 if (events & (POLLIN | POLLRDNORM)) { 1591 if (kq->kq_count) { 1592 revents |= events & (POLLIN | POLLRDNORM); 1593 } else { 1594 selrecord(td, &kq->kq_sel); 1595 if (SEL_WAITING(&kq->kq_sel)) 1596 kq->kq_state |= KQ_SEL; 1597 } 1598 } 1599 kqueue_release(kq, 1); 1600 KQ_UNLOCK(kq); 1601 return (revents); 1602 } 1603 1604 /*ARGSUSED*/ 1605 static int 1606 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1607 struct thread *td) 1608 { 1609 1610 bzero((void *)st, sizeof *st); 1611 /* 1612 * We no longer return kq_count because the unlocked value is useless. 1613 * If you spent all this time getting the count, why not spend your 1614 * syscall better by calling kevent? 1615 * 1616 * XXX - This is needed for libc_r. 1617 */ 1618 st->st_mode = S_IFIFO; 1619 return (0); 1620 } 1621 1622 /*ARGSUSED*/ 1623 static int 1624 kqueue_close(struct file *fp, struct thread *td) 1625 { 1626 struct kqueue *kq = fp->f_data; 1627 struct filedesc *fdp; 1628 struct knote *kn; 1629 int i; 1630 int error; 1631 1632 if ((error = kqueue_acquire(fp, &kq))) 1633 return error; 1634 1635 KQ_LOCK(kq); 1636 1637 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1638 ("kqueue already closing")); 1639 kq->kq_state |= KQ_CLOSING; 1640 if (kq->kq_refcnt > 1) 1641 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1642 1643 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1644 fdp = kq->kq_fdp; 1645 1646 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1647 ("kqueue's knlist not empty")); 1648 1649 for (i = 0; i < kq->kq_knlistsize; i++) { 1650 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1651 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1652 kq->kq_state |= KQ_FLUXWAIT; 1653 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1654 continue; 1655 } 1656 kn->kn_status |= KN_INFLUX; 1657 KQ_UNLOCK(kq); 1658 if (!(kn->kn_status & KN_DETACHED)) 1659 kn->kn_fop->f_detach(kn); 1660 knote_drop(kn, td); 1661 KQ_LOCK(kq); 1662 } 1663 } 1664 if (kq->kq_knhashmask != 0) { 1665 for (i = 0; i <= kq->kq_knhashmask; i++) { 1666 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1667 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1668 kq->kq_state |= KQ_FLUXWAIT; 1669 msleep(kq, &kq->kq_lock, PSOCK, 1670 "kqclo2", 0); 1671 continue; 1672 } 1673 kn->kn_status |= KN_INFLUX; 1674 KQ_UNLOCK(kq); 1675 if (!(kn->kn_status & KN_DETACHED)) 1676 kn->kn_fop->f_detach(kn); 1677 knote_drop(kn, td); 1678 KQ_LOCK(kq); 1679 } 1680 } 1681 } 1682 1683 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1684 kq->kq_state |= KQ_TASKDRAIN; 1685 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1686 } 1687 1688 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1689 selwakeuppri(&kq->kq_sel, PSOCK); 1690 if (!SEL_WAITING(&kq->kq_sel)) 1691 kq->kq_state &= ~KQ_SEL; 1692 } 1693 1694 KQ_UNLOCK(kq); 1695 1696 FILEDESC_XLOCK(fdp); 1697 SLIST_REMOVE(&fdp->fd_kqlist, kq, kqueue, kq_list); 1698 FILEDESC_XUNLOCK(fdp); 1699 1700 knlist_destroy(&kq->kq_sel.si_note); 1701 mtx_destroy(&kq->kq_lock); 1702 kq->kq_fdp = NULL; 1703 1704 if (kq->kq_knhash != NULL) 1705 free(kq->kq_knhash, M_KQUEUE); 1706 if (kq->kq_knlist != NULL) 1707 free(kq->kq_knlist, M_KQUEUE); 1708 1709 funsetown(&kq->kq_sigio); 1710 free(kq, M_KQUEUE); 1711 fp->f_data = NULL; 1712 1713 return (0); 1714 } 1715 1716 static void 1717 kqueue_wakeup(struct kqueue *kq) 1718 { 1719 KQ_OWNED(kq); 1720 1721 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1722 kq->kq_state &= ~KQ_SLEEP; 1723 wakeup(kq); 1724 } 1725 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1726 selwakeuppri(&kq->kq_sel, PSOCK); 1727 if (!SEL_WAITING(&kq->kq_sel)) 1728 kq->kq_state &= ~KQ_SEL; 1729 } 1730 if (!knlist_empty(&kq->kq_sel.si_note)) 1731 kqueue_schedtask(kq); 1732 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1733 pgsigio(&kq->kq_sigio, SIGIO, 0); 1734 } 1735 } 1736 1737 /* 1738 * Walk down a list of knotes, activating them if their event has triggered. 1739 * 1740 * There is a possibility to optimize in the case of one kq watching another. 1741 * Instead of scheduling a task to wake it up, you could pass enough state 1742 * down the chain to make up the parent kqueue. Make this code functional 1743 * first. 1744 */ 1745 void 1746 knote(struct knlist *list, long hint, int lockflags) 1747 { 1748 struct kqueue *kq; 1749 struct knote *kn; 1750 int error; 1751 1752 if (list == NULL) 1753 return; 1754 1755 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1756 1757 if ((lockflags & KNF_LISTLOCKED) == 0) 1758 list->kl_lock(list->kl_lockarg); 1759 1760 /* 1761 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1762 * the kqueue scheduling, but this will introduce four 1763 * lock/unlock's for each knote to test. If we do, continue to use 1764 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1765 * only safe if you want to remove the current item, which we are 1766 * not doing. 1767 */ 1768 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1769 kq = kn->kn_kq; 1770 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1771 KQ_LOCK(kq); 1772 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1773 KQ_UNLOCK(kq); 1774 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1775 kn->kn_status |= KN_INFLUX; 1776 KQ_UNLOCK(kq); 1777 error = kn->kn_fop->f_event(kn, hint); 1778 KQ_LOCK(kq); 1779 kn->kn_status &= ~KN_INFLUX; 1780 if (error) 1781 KNOTE_ACTIVATE(kn, 1); 1782 KQ_UNLOCK_FLUX(kq); 1783 } else { 1784 kn->kn_status |= KN_HASKQLOCK; 1785 if (kn->kn_fop->f_event(kn, hint)) 1786 KNOTE_ACTIVATE(kn, 1); 1787 kn->kn_status &= ~KN_HASKQLOCK; 1788 KQ_UNLOCK(kq); 1789 } 1790 } 1791 kq = NULL; 1792 } 1793 if ((lockflags & KNF_LISTLOCKED) == 0) 1794 list->kl_unlock(list->kl_lockarg); 1795 } 1796 1797 /* 1798 * add a knote to a knlist 1799 */ 1800 void 1801 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1802 { 1803 KNL_ASSERT_LOCK(knl, islocked); 1804 KQ_NOTOWNED(kn->kn_kq); 1805 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1806 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1807 if (!islocked) 1808 knl->kl_lock(knl->kl_lockarg); 1809 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1810 if (!islocked) 1811 knl->kl_unlock(knl->kl_lockarg); 1812 KQ_LOCK(kn->kn_kq); 1813 kn->kn_knlist = knl; 1814 kn->kn_status &= ~KN_DETACHED; 1815 KQ_UNLOCK(kn->kn_kq); 1816 } 1817 1818 static void 1819 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1820 { 1821 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1822 KNL_ASSERT_LOCK(knl, knlislocked); 1823 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1824 if (!kqislocked) 1825 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1826 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1827 if (!knlislocked) 1828 knl->kl_lock(knl->kl_lockarg); 1829 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1830 kn->kn_knlist = NULL; 1831 if (!knlislocked) 1832 knl->kl_unlock(knl->kl_lockarg); 1833 if (!kqislocked) 1834 KQ_LOCK(kn->kn_kq); 1835 kn->kn_status |= KN_DETACHED; 1836 if (!kqislocked) 1837 KQ_UNLOCK(kn->kn_kq); 1838 } 1839 1840 /* 1841 * remove all knotes from a specified klist 1842 */ 1843 void 1844 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1845 { 1846 1847 knlist_remove_kq(knl, kn, islocked, 0); 1848 } 1849 1850 /* 1851 * remove knote from a specified klist while in f_event handler. 1852 */ 1853 void 1854 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1855 { 1856 1857 knlist_remove_kq(knl, kn, 1, 1858 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1859 } 1860 1861 int 1862 knlist_empty(struct knlist *knl) 1863 { 1864 KNL_ASSERT_LOCKED(knl); 1865 return SLIST_EMPTY(&knl->kl_list); 1866 } 1867 1868 static struct mtx knlist_lock; 1869 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1870 MTX_DEF); 1871 static void knlist_mtx_lock(void *arg); 1872 static void knlist_mtx_unlock(void *arg); 1873 1874 static void 1875 knlist_mtx_lock(void *arg) 1876 { 1877 mtx_lock((struct mtx *)arg); 1878 } 1879 1880 static void 1881 knlist_mtx_unlock(void *arg) 1882 { 1883 mtx_unlock((struct mtx *)arg); 1884 } 1885 1886 static void 1887 knlist_mtx_assert_locked(void *arg) 1888 { 1889 mtx_assert((struct mtx *)arg, MA_OWNED); 1890 } 1891 1892 static void 1893 knlist_mtx_assert_unlocked(void *arg) 1894 { 1895 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1896 } 1897 1898 void 1899 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 1900 void (*kl_unlock)(void *), 1901 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 1902 { 1903 1904 if (lock == NULL) 1905 knl->kl_lockarg = &knlist_lock; 1906 else 1907 knl->kl_lockarg = lock; 1908 1909 if (kl_lock == NULL) 1910 knl->kl_lock = knlist_mtx_lock; 1911 else 1912 knl->kl_lock = kl_lock; 1913 if (kl_unlock == NULL) 1914 knl->kl_unlock = knlist_mtx_unlock; 1915 else 1916 knl->kl_unlock = kl_unlock; 1917 if (kl_assert_locked == NULL) 1918 knl->kl_assert_locked = knlist_mtx_assert_locked; 1919 else 1920 knl->kl_assert_locked = kl_assert_locked; 1921 if (kl_assert_unlocked == NULL) 1922 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 1923 else 1924 knl->kl_assert_unlocked = kl_assert_unlocked; 1925 1926 SLIST_INIT(&knl->kl_list); 1927 } 1928 1929 void 1930 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 1931 { 1932 1933 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 1934 } 1935 1936 void 1937 knlist_destroy(struct knlist *knl) 1938 { 1939 1940 #ifdef INVARIANTS 1941 /* 1942 * if we run across this error, we need to find the offending 1943 * driver and have it call knlist_clear. 1944 */ 1945 if (!SLIST_EMPTY(&knl->kl_list)) 1946 printf("WARNING: destroying knlist w/ knotes on it!\n"); 1947 #endif 1948 1949 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 1950 SLIST_INIT(&knl->kl_list); 1951 } 1952 1953 /* 1954 * Even if we are locked, we may need to drop the lock to allow any influx 1955 * knotes time to "settle". 1956 */ 1957 void 1958 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 1959 { 1960 struct knote *kn, *kn2; 1961 struct kqueue *kq; 1962 1963 if (islocked) 1964 KNL_ASSERT_LOCKED(knl); 1965 else { 1966 KNL_ASSERT_UNLOCKED(knl); 1967 again: /* need to reacquire lock since we have dropped it */ 1968 knl->kl_lock(knl->kl_lockarg); 1969 } 1970 1971 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 1972 kq = kn->kn_kq; 1973 KQ_LOCK(kq); 1974 if ((kn->kn_status & KN_INFLUX)) { 1975 KQ_UNLOCK(kq); 1976 continue; 1977 } 1978 knlist_remove_kq(knl, kn, 1, 1); 1979 if (killkn) { 1980 kn->kn_status |= KN_INFLUX | KN_DETACHED; 1981 KQ_UNLOCK(kq); 1982 knote_drop(kn, td); 1983 } else { 1984 /* Make sure cleared knotes disappear soon */ 1985 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 1986 KQ_UNLOCK(kq); 1987 } 1988 kq = NULL; 1989 } 1990 1991 if (!SLIST_EMPTY(&knl->kl_list)) { 1992 /* there are still KN_INFLUX remaining */ 1993 kn = SLIST_FIRST(&knl->kl_list); 1994 kq = kn->kn_kq; 1995 KQ_LOCK(kq); 1996 KASSERT(kn->kn_status & KN_INFLUX, 1997 ("knote removed w/o list lock")); 1998 knl->kl_unlock(knl->kl_lockarg); 1999 kq->kq_state |= KQ_FLUXWAIT; 2000 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2001 kq = NULL; 2002 goto again; 2003 } 2004 2005 if (islocked) 2006 KNL_ASSERT_LOCKED(knl); 2007 else { 2008 knl->kl_unlock(knl->kl_lockarg); 2009 KNL_ASSERT_UNLOCKED(knl); 2010 } 2011 } 2012 2013 /* 2014 * Remove all knotes referencing a specified fd must be called with FILEDESC 2015 * lock. This prevents a race where a new fd comes along and occupies the 2016 * entry and we attach a knote to the fd. 2017 */ 2018 void 2019 knote_fdclose(struct thread *td, int fd) 2020 { 2021 struct filedesc *fdp = td->td_proc->p_fd; 2022 struct kqueue *kq; 2023 struct knote *kn; 2024 int influx; 2025 2026 FILEDESC_XLOCK_ASSERT(fdp); 2027 2028 /* 2029 * We shouldn't have to worry about new kevents appearing on fd 2030 * since filedesc is locked. 2031 */ 2032 SLIST_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2033 KQ_LOCK(kq); 2034 2035 again: 2036 influx = 0; 2037 while (kq->kq_knlistsize > fd && 2038 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2039 if (kn->kn_status & KN_INFLUX) { 2040 /* someone else might be waiting on our knote */ 2041 if (influx) 2042 wakeup(kq); 2043 kq->kq_state |= KQ_FLUXWAIT; 2044 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2045 goto again; 2046 } 2047 kn->kn_status |= KN_INFLUX; 2048 KQ_UNLOCK(kq); 2049 if (!(kn->kn_status & KN_DETACHED)) 2050 kn->kn_fop->f_detach(kn); 2051 knote_drop(kn, td); 2052 influx = 1; 2053 KQ_LOCK(kq); 2054 } 2055 KQ_UNLOCK_FLUX(kq); 2056 } 2057 } 2058 2059 static int 2060 knote_attach(struct knote *kn, struct kqueue *kq) 2061 { 2062 struct klist *list; 2063 2064 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2065 KQ_OWNED(kq); 2066 2067 if (kn->kn_fop->f_isfd) { 2068 if (kn->kn_id >= kq->kq_knlistsize) 2069 return ENOMEM; 2070 list = &kq->kq_knlist[kn->kn_id]; 2071 } else { 2072 if (kq->kq_knhash == NULL) 2073 return ENOMEM; 2074 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2075 } 2076 2077 SLIST_INSERT_HEAD(list, kn, kn_link); 2078 2079 return 0; 2080 } 2081 2082 /* 2083 * knote must already have been detached using the f_detach method. 2084 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2085 * to prevent other removal. 2086 */ 2087 static void 2088 knote_drop(struct knote *kn, struct thread *td) 2089 { 2090 struct kqueue *kq; 2091 struct klist *list; 2092 2093 kq = kn->kn_kq; 2094 2095 KQ_NOTOWNED(kq); 2096 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2097 ("knote_drop called without KN_INFLUX set in kn_status")); 2098 2099 KQ_LOCK(kq); 2100 if (kn->kn_fop->f_isfd) 2101 list = &kq->kq_knlist[kn->kn_id]; 2102 else 2103 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2104 2105 if (!SLIST_EMPTY(list)) 2106 SLIST_REMOVE(list, kn, knote, kn_link); 2107 if (kn->kn_status & KN_QUEUED) 2108 knote_dequeue(kn); 2109 KQ_UNLOCK_FLUX(kq); 2110 2111 if (kn->kn_fop->f_isfd) { 2112 fdrop(kn->kn_fp, td); 2113 kn->kn_fp = NULL; 2114 } 2115 kqueue_fo_release(kn->kn_kevent.filter); 2116 kn->kn_fop = NULL; 2117 knote_free(kn); 2118 } 2119 2120 static void 2121 knote_enqueue(struct knote *kn) 2122 { 2123 struct kqueue *kq = kn->kn_kq; 2124 2125 KQ_OWNED(kn->kn_kq); 2126 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2127 2128 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2129 kn->kn_status |= KN_QUEUED; 2130 kq->kq_count++; 2131 kqueue_wakeup(kq); 2132 } 2133 2134 static void 2135 knote_dequeue(struct knote *kn) 2136 { 2137 struct kqueue *kq = kn->kn_kq; 2138 2139 KQ_OWNED(kn->kn_kq); 2140 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2141 2142 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2143 kn->kn_status &= ~KN_QUEUED; 2144 kq->kq_count--; 2145 } 2146 2147 static void 2148 knote_init(void) 2149 { 2150 2151 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2152 NULL, NULL, UMA_ALIGN_PTR, 0); 2153 } 2154 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2155 2156 static struct knote * 2157 knote_alloc(int waitok) 2158 { 2159 return ((struct knote *)uma_zalloc(knote_zone, 2160 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2161 } 2162 2163 static void 2164 knote_free(struct knote *kn) 2165 { 2166 if (kn != NULL) 2167 uma_zfree(knote_zone, kn); 2168 } 2169 2170 /* 2171 * Register the kev w/ the kq specified by fd. 2172 */ 2173 int 2174 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2175 { 2176 struct kqueue *kq; 2177 struct file *fp; 2178 int error; 2179 2180 if ((error = fget(td, fd, &fp)) != 0) 2181 return (error); 2182 if ((error = kqueue_acquire(fp, &kq)) != 0) 2183 goto noacquire; 2184 2185 error = kqueue_register(kq, kev, td, waitok); 2186 2187 kqueue_release(kq, 0); 2188 2189 noacquire: 2190 fdrop(fp, td); 2191 2192 return error; 2193 } 2194