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 #include "opt_kqueue.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/capsicum.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/rwlock.h> 42 #include <sys/proc.h> 43 #include <sys/malloc.h> 44 #include <sys/unistd.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/filio.h> 48 #include <sys/fcntl.h> 49 #include <sys/kthread.h> 50 #include <sys/selinfo.h> 51 #include <sys/queue.h> 52 #include <sys/event.h> 53 #include <sys/eventvar.h> 54 #include <sys/poll.h> 55 #include <sys/protosw.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sigio.h> 58 #include <sys/signalvar.h> 59 #include <sys/socket.h> 60 #include <sys/socketvar.h> 61 #include <sys/stat.h> 62 #include <sys/sysctl.h> 63 #include <sys/sysproto.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/taskqueue.h> 66 #include <sys/uio.h> 67 #include <sys/user.h> 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 #include <machine/atomic.h> 72 73 #include <vm/uma.h> 74 75 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 76 77 /* 78 * This lock is used if multiple kq locks are required. This possibly 79 * should be made into a per proc lock. 80 */ 81 static struct mtx kq_global; 82 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 83 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 84 if (!haslck) \ 85 mtx_lock(lck); \ 86 haslck = 1; \ 87 } while (0) 88 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 89 if (haslck) \ 90 mtx_unlock(lck); \ 91 haslck = 0; \ 92 } while (0) 93 94 TASKQUEUE_DEFINE_THREAD(kqueue_ctx); 95 96 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 97 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 98 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 99 struct thread *td, int waitok); 100 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 101 static void kqueue_release(struct kqueue *kq, int locked); 102 static void kqueue_destroy(struct kqueue *kq); 103 static void kqueue_drain(struct kqueue *kq, struct thread *td); 104 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 105 uintptr_t ident, int waitok); 106 static void kqueue_task(void *arg, int pending); 107 static int kqueue_scan(struct kqueue *kq, int maxevents, 108 struct kevent_copyops *k_ops, 109 const struct timespec *timeout, 110 struct kevent *keva, struct thread *td); 111 static void kqueue_wakeup(struct kqueue *kq); 112 static struct filterops *kqueue_fo_find(int filt); 113 static void kqueue_fo_release(int filt); 114 115 static fo_ioctl_t kqueue_ioctl; 116 static fo_poll_t kqueue_poll; 117 static fo_kqfilter_t kqueue_kqfilter; 118 static fo_stat_t kqueue_stat; 119 static fo_close_t kqueue_close; 120 static fo_fill_kinfo_t kqueue_fill_kinfo; 121 122 static struct fileops kqueueops = { 123 .fo_read = invfo_rdwr, 124 .fo_write = invfo_rdwr, 125 .fo_truncate = invfo_truncate, 126 .fo_ioctl = kqueue_ioctl, 127 .fo_poll = kqueue_poll, 128 .fo_kqfilter = kqueue_kqfilter, 129 .fo_stat = kqueue_stat, 130 .fo_close = kqueue_close, 131 .fo_chmod = invfo_chmod, 132 .fo_chown = invfo_chown, 133 .fo_sendfile = invfo_sendfile, 134 .fo_fill_kinfo = kqueue_fill_kinfo, 135 }; 136 137 static int knote_attach(struct knote *kn, struct kqueue *kq); 138 static void knote_drop(struct knote *kn, struct thread *td); 139 static void knote_drop_detached(struct knote *kn, struct thread *td); 140 static void knote_enqueue(struct knote *kn); 141 static void knote_dequeue(struct knote *kn); 142 static void knote_init(void); 143 static struct knote *knote_alloc(int waitok); 144 static void knote_free(struct knote *kn); 145 146 static void filt_kqdetach(struct knote *kn); 147 static int filt_kqueue(struct knote *kn, long hint); 148 static int filt_procattach(struct knote *kn); 149 static void filt_procdetach(struct knote *kn); 150 static int filt_proc(struct knote *kn, long hint); 151 static int filt_fileattach(struct knote *kn); 152 static void filt_timerexpire(void *knx); 153 static int filt_timerattach(struct knote *kn); 154 static void filt_timerdetach(struct knote *kn); 155 static int filt_timer(struct knote *kn, long hint); 156 static int filt_userattach(struct knote *kn); 157 static void filt_userdetach(struct knote *kn); 158 static int filt_user(struct knote *kn, long hint); 159 static void filt_usertouch(struct knote *kn, struct kevent *kev, 160 u_long type); 161 162 static struct filterops file_filtops = { 163 .f_isfd = 1, 164 .f_attach = filt_fileattach, 165 }; 166 static struct filterops kqread_filtops = { 167 .f_isfd = 1, 168 .f_detach = filt_kqdetach, 169 .f_event = filt_kqueue, 170 }; 171 /* XXX - move to kern_proc.c? */ 172 static struct filterops proc_filtops = { 173 .f_isfd = 0, 174 .f_attach = filt_procattach, 175 .f_detach = filt_procdetach, 176 .f_event = filt_proc, 177 }; 178 static struct filterops timer_filtops = { 179 .f_isfd = 0, 180 .f_attach = filt_timerattach, 181 .f_detach = filt_timerdetach, 182 .f_event = filt_timer, 183 }; 184 static struct filterops user_filtops = { 185 .f_attach = filt_userattach, 186 .f_detach = filt_userdetach, 187 .f_event = filt_user, 188 .f_touch = filt_usertouch, 189 }; 190 191 static uma_zone_t knote_zone; 192 static unsigned int kq_ncallouts = 0; 193 static unsigned int kq_calloutmax = 4 * 1024; 194 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 195 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 196 197 /* XXX - ensure not influx ? */ 198 #define KNOTE_ACTIVATE(kn, islock) do { \ 199 if ((islock)) \ 200 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 201 else \ 202 KQ_LOCK((kn)->kn_kq); \ 203 (kn)->kn_status |= KN_ACTIVE; \ 204 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 205 knote_enqueue((kn)); \ 206 if (!(islock)) \ 207 KQ_UNLOCK((kn)->kn_kq); \ 208 } while(0) 209 #define KQ_LOCK(kq) do { \ 210 mtx_lock(&(kq)->kq_lock); \ 211 } while (0) 212 #define KQ_FLUX_WAKEUP(kq) do { \ 213 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 214 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 215 wakeup((kq)); \ 216 } \ 217 } while (0) 218 #define KQ_UNLOCK_FLUX(kq) do { \ 219 KQ_FLUX_WAKEUP(kq); \ 220 mtx_unlock(&(kq)->kq_lock); \ 221 } while (0) 222 #define KQ_UNLOCK(kq) do { \ 223 mtx_unlock(&(kq)->kq_lock); \ 224 } while (0) 225 #define KQ_OWNED(kq) do { \ 226 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 227 } while (0) 228 #define KQ_NOTOWNED(kq) do { \ 229 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 230 } while (0) 231 232 static struct knlist * 233 kn_list_lock(struct knote *kn) 234 { 235 struct knlist *knl; 236 237 knl = kn->kn_knlist; 238 if (knl != NULL) 239 knl->kl_lock(knl->kl_lockarg); 240 return (knl); 241 } 242 243 static void 244 kn_list_unlock(struct knlist *knl) 245 { 246 bool do_free; 247 248 if (knl == NULL) 249 return; 250 do_free = knl->kl_autodestroy && knlist_empty(knl); 251 knl->kl_unlock(knl->kl_lockarg); 252 if (do_free) { 253 knlist_destroy(knl); 254 free(knl, M_KQUEUE); 255 } 256 } 257 258 static bool 259 kn_in_flux(struct knote *kn) 260 { 261 262 return (kn->kn_influx > 0); 263 } 264 265 static void 266 kn_enter_flux(struct knote *kn) 267 { 268 269 KQ_OWNED(kn->kn_kq); 270 MPASS(kn->kn_influx < INT_MAX); 271 kn->kn_influx++; 272 } 273 274 static bool 275 kn_leave_flux(struct knote *kn) 276 { 277 278 KQ_OWNED(kn->kn_kq); 279 MPASS(kn->kn_influx > 0); 280 kn->kn_influx--; 281 return (kn->kn_influx == 0); 282 } 283 284 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 285 if (islocked) \ 286 KNL_ASSERT_LOCKED(knl); \ 287 else \ 288 KNL_ASSERT_UNLOCKED(knl); \ 289 } while (0) 290 #ifdef INVARIANTS 291 #define KNL_ASSERT_LOCKED(knl) do { \ 292 knl->kl_assert_locked((knl)->kl_lockarg); \ 293 } while (0) 294 #define KNL_ASSERT_UNLOCKED(knl) do { \ 295 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 296 } while (0) 297 #else /* !INVARIANTS */ 298 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 299 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 300 #endif /* INVARIANTS */ 301 302 #ifndef KN_HASHSIZE 303 #define KN_HASHSIZE 64 /* XXX should be tunable */ 304 #endif 305 306 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 307 308 static int 309 filt_nullattach(struct knote *kn) 310 { 311 312 return (ENXIO); 313 }; 314 315 struct filterops null_filtops = { 316 .f_isfd = 0, 317 .f_attach = filt_nullattach, 318 }; 319 320 /* XXX - make SYSINIT to add these, and move into respective modules. */ 321 extern struct filterops sig_filtops; 322 extern struct filterops fs_filtops; 323 324 /* 325 * Table for for all system-defined filters. 326 */ 327 static struct mtx filterops_lock; 328 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 329 MTX_DEF); 330 static struct { 331 struct filterops *for_fop; 332 int for_nolock; 333 int for_refcnt; 334 } sysfilt_ops[EVFILT_SYSCOUNT] = { 335 { &file_filtops, 1 }, /* EVFILT_READ */ 336 { &file_filtops, 1 }, /* EVFILT_WRITE */ 337 { &null_filtops }, /* EVFILT_AIO */ 338 { &file_filtops, 1 }, /* EVFILT_VNODE */ 339 { &proc_filtops, 1 }, /* EVFILT_PROC */ 340 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 341 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 342 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 343 { &fs_filtops, 1 }, /* EVFILT_FS */ 344 { &null_filtops }, /* EVFILT_LIO */ 345 { &user_filtops, 1 }, /* EVFILT_USER */ 346 { &null_filtops }, /* EVFILT_SENDFILE */ 347 { &file_filtops, 1 }, /* EVFILT_EMPTY */ 348 }; 349 350 /* 351 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 352 * method. 353 */ 354 static int 355 filt_fileattach(struct knote *kn) 356 { 357 358 return (fo_kqfilter(kn->kn_fp, kn)); 359 } 360 361 /*ARGSUSED*/ 362 static int 363 kqueue_kqfilter(struct file *fp, struct knote *kn) 364 { 365 struct kqueue *kq = kn->kn_fp->f_data; 366 367 if (kn->kn_filter != EVFILT_READ) 368 return (EINVAL); 369 370 kn->kn_status |= KN_KQUEUE; 371 kn->kn_fop = &kqread_filtops; 372 knlist_add(&kq->kq_sel.si_note, kn, 0); 373 374 return (0); 375 } 376 377 static void 378 filt_kqdetach(struct knote *kn) 379 { 380 struct kqueue *kq = kn->kn_fp->f_data; 381 382 knlist_remove(&kq->kq_sel.si_note, kn, 0); 383 } 384 385 /*ARGSUSED*/ 386 static int 387 filt_kqueue(struct knote *kn, long hint) 388 { 389 struct kqueue *kq = kn->kn_fp->f_data; 390 391 kn->kn_data = kq->kq_count; 392 return (kn->kn_data > 0); 393 } 394 395 /* XXX - move to kern_proc.c? */ 396 static int 397 filt_procattach(struct knote *kn) 398 { 399 struct proc *p; 400 int error; 401 bool exiting, immediate; 402 403 exiting = immediate = false; 404 p = pfind(kn->kn_id); 405 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 406 p = zpfind(kn->kn_id); 407 exiting = true; 408 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 409 exiting = true; 410 } 411 412 if (p == NULL) 413 return (ESRCH); 414 if ((error = p_cansee(curthread, p))) { 415 PROC_UNLOCK(p); 416 return (error); 417 } 418 419 kn->kn_ptr.p_proc = p; 420 kn->kn_flags |= EV_CLEAR; /* automatically set */ 421 422 /* 423 * Internal flag indicating registration done by kernel for the 424 * purposes of getting a NOTE_CHILD notification. 425 */ 426 if (kn->kn_flags & EV_FLAG2) { 427 kn->kn_flags &= ~EV_FLAG2; 428 kn->kn_data = kn->kn_sdata; /* ppid */ 429 kn->kn_fflags = NOTE_CHILD; 430 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK); 431 immediate = true; /* Force immediate activation of child note. */ 432 } 433 /* 434 * Internal flag indicating registration done by kernel (for other than 435 * NOTE_CHILD). 436 */ 437 if (kn->kn_flags & EV_FLAG1) { 438 kn->kn_flags &= ~EV_FLAG1; 439 } 440 441 knlist_add(p->p_klist, kn, 1); 442 443 /* 444 * Immediately activate any child notes or, in the case of a zombie 445 * target process, exit notes. The latter is necessary to handle the 446 * case where the target process, e.g. a child, dies before the kevent 447 * is registered. 448 */ 449 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT))) 450 KNOTE_ACTIVATE(kn, 0); 451 452 PROC_UNLOCK(p); 453 454 return (0); 455 } 456 457 /* 458 * The knote may be attached to a different process, which may exit, 459 * leaving nothing for the knote to be attached to. So when the process 460 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 461 * it will be deleted when read out. However, as part of the knote deletion, 462 * this routine is called, so a check is needed to avoid actually performing 463 * a detach, because the original process does not exist any more. 464 */ 465 /* XXX - move to kern_proc.c? */ 466 static void 467 filt_procdetach(struct knote *kn) 468 { 469 470 knlist_remove(kn->kn_knlist, kn, 0); 471 kn->kn_ptr.p_proc = NULL; 472 } 473 474 /* XXX - move to kern_proc.c? */ 475 static int 476 filt_proc(struct knote *kn, long hint) 477 { 478 struct proc *p; 479 u_int event; 480 481 p = kn->kn_ptr.p_proc; 482 if (p == NULL) /* already activated, from attach filter */ 483 return (0); 484 485 /* Mask off extra data. */ 486 event = (u_int)hint & NOTE_PCTRLMASK; 487 488 /* If the user is interested in this event, record it. */ 489 if (kn->kn_sfflags & event) 490 kn->kn_fflags |= event; 491 492 /* Process is gone, so flag the event as finished. */ 493 if (event == NOTE_EXIT) { 494 kn->kn_flags |= EV_EOF | EV_ONESHOT; 495 kn->kn_ptr.p_proc = NULL; 496 if (kn->kn_fflags & NOTE_EXIT) 497 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 498 if (kn->kn_fflags == 0) 499 kn->kn_flags |= EV_DROP; 500 return (1); 501 } 502 503 return (kn->kn_fflags != 0); 504 } 505 506 /* 507 * Called when the process forked. It mostly does the same as the 508 * knote(), activating all knotes registered to be activated when the 509 * process forked. Additionally, for each knote attached to the 510 * parent, check whether user wants to track the new process. If so 511 * attach a new knote to it, and immediately report an event with the 512 * child's pid. 513 */ 514 void 515 knote_fork(struct knlist *list, int pid) 516 { 517 struct kqueue *kq; 518 struct knote *kn; 519 struct kevent kev; 520 int error; 521 522 if (list == NULL) 523 return; 524 list->kl_lock(list->kl_lockarg); 525 526 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 527 kq = kn->kn_kq; 528 KQ_LOCK(kq); 529 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 530 KQ_UNLOCK(kq); 531 continue; 532 } 533 534 /* 535 * The same as knote(), activate the event. 536 */ 537 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 538 kn->kn_status |= KN_HASKQLOCK; 539 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 540 KNOTE_ACTIVATE(kn, 1); 541 kn->kn_status &= ~KN_HASKQLOCK; 542 KQ_UNLOCK(kq); 543 continue; 544 } 545 546 /* 547 * The NOTE_TRACK case. In addition to the activation 548 * of the event, we need to register new events to 549 * track the child. Drop the locks in preparation for 550 * the call to kqueue_register(). 551 */ 552 kn_enter_flux(kn); 553 KQ_UNLOCK(kq); 554 list->kl_unlock(list->kl_lockarg); 555 556 /* 557 * Activate existing knote and register tracking knotes with 558 * new process. 559 * 560 * First register a knote to get just the child notice. This 561 * must be a separate note from a potential NOTE_EXIT 562 * notification since both NOTE_CHILD and NOTE_EXIT are defined 563 * to use the data field (in conflicting ways). 564 */ 565 kev.ident = pid; 566 kev.filter = kn->kn_filter; 567 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | 568 EV_FLAG2; 569 kev.fflags = kn->kn_sfflags; 570 kev.data = kn->kn_id; /* parent */ 571 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 572 error = kqueue_register(kq, &kev, NULL, 0); 573 if (error) 574 kn->kn_fflags |= NOTE_TRACKERR; 575 576 /* 577 * Then register another knote to track other potential events 578 * from the new process. 579 */ 580 kev.ident = pid; 581 kev.filter = kn->kn_filter; 582 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 583 kev.fflags = kn->kn_sfflags; 584 kev.data = kn->kn_id; /* parent */ 585 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 586 error = kqueue_register(kq, &kev, NULL, 0); 587 if (error) 588 kn->kn_fflags |= NOTE_TRACKERR; 589 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 590 KNOTE_ACTIVATE(kn, 0); 591 KQ_LOCK(kq); 592 kn_leave_flux(kn); 593 KQ_UNLOCK_FLUX(kq); 594 list->kl_lock(list->kl_lockarg); 595 } 596 list->kl_unlock(list->kl_lockarg); 597 } 598 599 /* 600 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 601 * interval timer support code. 602 */ 603 604 #define NOTE_TIMER_PRECMASK (NOTE_SECONDS|NOTE_MSECONDS|NOTE_USECONDS| \ 605 NOTE_NSECONDS) 606 607 static sbintime_t 608 timer2sbintime(intptr_t data, int flags) 609 { 610 611 /* 612 * Macros for converting to the fractional second portion of an 613 * sbintime_t using 64bit multiplication to improve precision. 614 */ 615 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 616 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 617 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 618 switch (flags & NOTE_TIMER_PRECMASK) { 619 case NOTE_SECONDS: 620 #ifdef __LP64__ 621 if (data > (SBT_MAX / SBT_1S)) 622 return (SBT_MAX); 623 #endif 624 return ((sbintime_t)data << 32); 625 case NOTE_MSECONDS: /* FALLTHROUGH */ 626 case 0: 627 if (data >= 1000) { 628 int64_t secs = data / 1000; 629 #ifdef __LP64__ 630 if (secs > (SBT_MAX / SBT_1S)) 631 return (SBT_MAX); 632 #endif 633 return (secs << 32 | MS_TO_SBT(data % 1000)); 634 } 635 return MS_TO_SBT(data); 636 case NOTE_USECONDS: 637 if (data >= 1000000) { 638 int64_t secs = data / 1000000; 639 #ifdef __LP64__ 640 if (secs > (SBT_MAX / SBT_1S)) 641 return (SBT_MAX); 642 #endif 643 return (secs << 32 | US_TO_SBT(data % 1000000)); 644 } 645 return US_TO_SBT(data); 646 case NOTE_NSECONDS: 647 if (data >= 1000000000) { 648 int64_t secs = data / 1000000000; 649 #ifdef __LP64__ 650 if (secs > (SBT_MAX / SBT_1S)) 651 return (SBT_MAX); 652 #endif 653 return (secs << 32 | US_TO_SBT(data % 1000000000)); 654 } 655 return (NS_TO_SBT(data)); 656 default: 657 break; 658 } 659 return (-1); 660 } 661 662 struct kq_timer_cb_data { 663 struct callout c; 664 sbintime_t next; /* next timer event fires at */ 665 sbintime_t to; /* precalculated timer period */ 666 }; 667 668 static void 669 filt_timerexpire(void *knx) 670 { 671 struct knote *kn; 672 struct kq_timer_cb_data *kc; 673 674 kn = knx; 675 kn->kn_data++; 676 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 677 678 if ((kn->kn_flags & EV_ONESHOT) != 0) 679 return; 680 681 kc = kn->kn_ptr.p_v; 682 kc->next += kc->to; 683 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 684 PCPU_GET(cpuid), C_ABSOLUTE); 685 } 686 687 /* 688 * data contains amount of time to sleep 689 */ 690 static int 691 filt_timerattach(struct knote *kn) 692 { 693 struct kq_timer_cb_data *kc; 694 sbintime_t to; 695 unsigned int ncallouts; 696 697 if (kn->kn_sdata < 0) 698 return (EINVAL); 699 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 700 kn->kn_sdata = 1; 701 /* Only precision unit are supported in flags so far */ 702 if ((kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) != 0) 703 return (EINVAL); 704 705 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 706 if (to < 0) 707 return (EINVAL); 708 709 do { 710 ncallouts = kq_ncallouts; 711 if (ncallouts >= kq_calloutmax) 712 return (ENOMEM); 713 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 714 715 kn->kn_flags |= EV_CLEAR; /* automatically set */ 716 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 717 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 718 callout_init(&kc->c, 1); 719 kc->next = to + sbinuptime(); 720 kc->to = to; 721 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 722 PCPU_GET(cpuid), C_ABSOLUTE); 723 724 return (0); 725 } 726 727 static void 728 filt_timerdetach(struct knote *kn) 729 { 730 struct kq_timer_cb_data *kc; 731 unsigned int old; 732 733 kc = kn->kn_ptr.p_v; 734 callout_drain(&kc->c); 735 free(kc, M_KQUEUE); 736 old = atomic_fetchadd_int(&kq_ncallouts, -1); 737 KASSERT(old > 0, ("Number of callouts cannot become negative")); 738 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 739 } 740 741 static int 742 filt_timer(struct knote *kn, long hint) 743 { 744 745 return (kn->kn_data != 0); 746 } 747 748 static int 749 filt_userattach(struct knote *kn) 750 { 751 752 /* 753 * EVFILT_USER knotes are not attached to anything in the kernel. 754 */ 755 kn->kn_hook = NULL; 756 if (kn->kn_fflags & NOTE_TRIGGER) 757 kn->kn_hookid = 1; 758 else 759 kn->kn_hookid = 0; 760 return (0); 761 } 762 763 static void 764 filt_userdetach(__unused struct knote *kn) 765 { 766 767 /* 768 * EVFILT_USER knotes are not attached to anything in the kernel. 769 */ 770 } 771 772 static int 773 filt_user(struct knote *kn, __unused long hint) 774 { 775 776 return (kn->kn_hookid); 777 } 778 779 static void 780 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 781 { 782 u_int ffctrl; 783 784 switch (type) { 785 case EVENT_REGISTER: 786 if (kev->fflags & NOTE_TRIGGER) 787 kn->kn_hookid = 1; 788 789 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 790 kev->fflags &= NOTE_FFLAGSMASK; 791 switch (ffctrl) { 792 case NOTE_FFNOP: 793 break; 794 795 case NOTE_FFAND: 796 kn->kn_sfflags &= kev->fflags; 797 break; 798 799 case NOTE_FFOR: 800 kn->kn_sfflags |= kev->fflags; 801 break; 802 803 case NOTE_FFCOPY: 804 kn->kn_sfflags = kev->fflags; 805 break; 806 807 default: 808 /* XXX Return error? */ 809 break; 810 } 811 kn->kn_sdata = kev->data; 812 if (kev->flags & EV_CLEAR) { 813 kn->kn_hookid = 0; 814 kn->kn_data = 0; 815 kn->kn_fflags = 0; 816 } 817 break; 818 819 case EVENT_PROCESS: 820 *kev = kn->kn_kevent; 821 kev->fflags = kn->kn_sfflags; 822 kev->data = kn->kn_sdata; 823 if (kn->kn_flags & EV_CLEAR) { 824 kn->kn_hookid = 0; 825 kn->kn_data = 0; 826 kn->kn_fflags = 0; 827 } 828 break; 829 830 default: 831 panic("filt_usertouch() - invalid type (%ld)", type); 832 break; 833 } 834 } 835 836 int 837 sys_kqueue(struct thread *td, struct kqueue_args *uap) 838 { 839 840 return (kern_kqueue(td, 0, NULL)); 841 } 842 843 static void 844 kqueue_init(struct kqueue *kq) 845 { 846 847 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 848 TAILQ_INIT(&kq->kq_head); 849 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 850 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 851 } 852 853 int 854 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 855 { 856 struct filedesc *fdp; 857 struct kqueue *kq; 858 struct file *fp; 859 struct ucred *cred; 860 int fd, error; 861 862 fdp = td->td_proc->p_fd; 863 cred = td->td_ucred; 864 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 865 return (ENOMEM); 866 867 error = falloc_caps(td, &fp, &fd, flags, fcaps); 868 if (error != 0) { 869 chgkqcnt(cred->cr_ruidinfo, -1, 0); 870 return (error); 871 } 872 873 /* An extra reference on `fp' has been held for us by falloc(). */ 874 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 875 kqueue_init(kq); 876 kq->kq_fdp = fdp; 877 kq->kq_cred = crhold(cred); 878 879 FILEDESC_XLOCK(fdp); 880 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 881 FILEDESC_XUNLOCK(fdp); 882 883 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 884 fdrop(fp, td); 885 886 td->td_retval[0] = fd; 887 return (0); 888 } 889 890 static size_t 891 kev_iovlen(int n, u_int kgio) 892 { 893 894 if (n < 0 || n >= kgio / sizeof(struct kevent)) 895 return (kgio); 896 return (n * sizeof(struct kevent)); 897 } 898 899 #ifndef _SYS_SYSPROTO_H_ 900 struct kevent_args { 901 int fd; 902 const struct kevent *changelist; 903 int nchanges; 904 struct kevent *eventlist; 905 int nevents; 906 const struct timespec *timeout; 907 }; 908 #endif 909 int 910 sys_kevent(struct thread *td, struct kevent_args *uap) 911 { 912 struct timespec ts, *tsp; 913 struct kevent_copyops k_ops = { uap, 914 kevent_copyout, 915 kevent_copyin}; 916 int error; 917 #ifdef KTRACE 918 struct uio ktruio; 919 struct iovec ktriov; 920 struct uio *ktruioin = NULL; 921 struct uio *ktruioout = NULL; 922 u_int kgio; 923 #endif 924 925 if (uap->timeout != NULL) { 926 error = copyin(uap->timeout, &ts, sizeof(ts)); 927 if (error) 928 return (error); 929 tsp = &ts; 930 } else 931 tsp = NULL; 932 933 #ifdef KTRACE 934 if (KTRPOINT(td, KTR_GENIO)) { 935 kgio = ktr_geniosize; 936 ktriov.iov_base = uap->changelist; 937 ktriov.iov_len = kev_iovlen(uap->nchanges, kgio); 938 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 939 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 940 .uio_td = td }; 941 ktruioin = cloneuio(&ktruio); 942 ktriov.iov_base = uap->eventlist; 943 ktriov.iov_len = kev_iovlen(uap->nevents, kgio); 944 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 945 ktruioout = cloneuio(&ktruio); 946 } 947 #endif 948 949 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 950 &k_ops, tsp); 951 952 #ifdef KTRACE 953 if (ktruioin != NULL) { 954 ktruioin->uio_resid = kev_iovlen(uap->nchanges, kgio); 955 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 956 ktruioout->uio_resid = kev_iovlen(td->td_retval[0], kgio); 957 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 958 } 959 #endif 960 961 return (error); 962 } 963 964 /* 965 * Copy 'count' items into the destination list pointed to by uap->eventlist. 966 */ 967 static int 968 kevent_copyout(void *arg, struct kevent *kevp, int count) 969 { 970 struct kevent_args *uap; 971 int error; 972 973 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 974 uap = (struct kevent_args *)arg; 975 976 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 977 if (error == 0) 978 uap->eventlist += count; 979 return (error); 980 } 981 982 /* 983 * Copy 'count' items from the list pointed to by uap->changelist. 984 */ 985 static int 986 kevent_copyin(void *arg, struct kevent *kevp, int count) 987 { 988 struct kevent_args *uap; 989 int error; 990 991 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 992 uap = (struct kevent_args *)arg; 993 994 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 995 if (error == 0) 996 uap->changelist += count; 997 return (error); 998 } 999 1000 int 1001 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1002 struct kevent_copyops *k_ops, const struct timespec *timeout) 1003 { 1004 cap_rights_t rights; 1005 struct file *fp; 1006 int error; 1007 1008 cap_rights_init(&rights); 1009 if (nchanges > 0) 1010 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 1011 if (nevents > 0) 1012 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 1013 error = fget(td, fd, &rights, &fp); 1014 if (error != 0) 1015 return (error); 1016 1017 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1018 fdrop(fp, td); 1019 1020 return (error); 1021 } 1022 1023 static int 1024 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1025 struct kevent_copyops *k_ops, const struct timespec *timeout) 1026 { 1027 struct kevent keva[KQ_NEVENTS]; 1028 struct kevent *kevp, *changes; 1029 int i, n, nerrors, error; 1030 1031 nerrors = 0; 1032 while (nchanges > 0) { 1033 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1034 error = k_ops->k_copyin(k_ops->arg, keva, n); 1035 if (error) 1036 return (error); 1037 changes = keva; 1038 for (i = 0; i < n; i++) { 1039 kevp = &changes[i]; 1040 if (!kevp->filter) 1041 continue; 1042 kevp->flags &= ~EV_SYSFLAGS; 1043 error = kqueue_register(kq, kevp, td, 1); 1044 if (error || (kevp->flags & EV_RECEIPT)) { 1045 if (nevents == 0) 1046 return (error); 1047 kevp->flags = EV_ERROR; 1048 kevp->data = error; 1049 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1050 nevents--; 1051 nerrors++; 1052 } 1053 } 1054 nchanges -= n; 1055 } 1056 if (nerrors) { 1057 td->td_retval[0] = nerrors; 1058 return (0); 1059 } 1060 1061 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1062 } 1063 1064 int 1065 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1066 struct kevent_copyops *k_ops, const struct timespec *timeout) 1067 { 1068 struct kqueue *kq; 1069 int error; 1070 1071 error = kqueue_acquire(fp, &kq); 1072 if (error != 0) 1073 return (error); 1074 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1075 kqueue_release(kq, 0); 1076 return (error); 1077 } 1078 1079 /* 1080 * Performs a kevent() call on a temporarily created kqueue. This can be 1081 * used to perform one-shot polling, similar to poll() and select(). 1082 */ 1083 int 1084 kern_kevent_anonymous(struct thread *td, int nevents, 1085 struct kevent_copyops *k_ops) 1086 { 1087 struct kqueue kq = {}; 1088 int error; 1089 1090 kqueue_init(&kq); 1091 kq.kq_refcnt = 1; 1092 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1093 kqueue_drain(&kq, td); 1094 kqueue_destroy(&kq); 1095 return (error); 1096 } 1097 1098 int 1099 kqueue_add_filteropts(int filt, struct filterops *filtops) 1100 { 1101 int error; 1102 1103 error = 0; 1104 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1105 printf( 1106 "trying to add a filterop that is out of range: %d is beyond %d\n", 1107 ~filt, EVFILT_SYSCOUNT); 1108 return EINVAL; 1109 } 1110 mtx_lock(&filterops_lock); 1111 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1112 sysfilt_ops[~filt].for_fop != NULL) 1113 error = EEXIST; 1114 else { 1115 sysfilt_ops[~filt].for_fop = filtops; 1116 sysfilt_ops[~filt].for_refcnt = 0; 1117 } 1118 mtx_unlock(&filterops_lock); 1119 1120 return (error); 1121 } 1122 1123 int 1124 kqueue_del_filteropts(int filt) 1125 { 1126 int error; 1127 1128 error = 0; 1129 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1130 return EINVAL; 1131 1132 mtx_lock(&filterops_lock); 1133 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1134 sysfilt_ops[~filt].for_fop == NULL) 1135 error = EINVAL; 1136 else if (sysfilt_ops[~filt].for_refcnt != 0) 1137 error = EBUSY; 1138 else { 1139 sysfilt_ops[~filt].for_fop = &null_filtops; 1140 sysfilt_ops[~filt].for_refcnt = 0; 1141 } 1142 mtx_unlock(&filterops_lock); 1143 1144 return error; 1145 } 1146 1147 static struct filterops * 1148 kqueue_fo_find(int filt) 1149 { 1150 1151 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1152 return NULL; 1153 1154 if (sysfilt_ops[~filt].for_nolock) 1155 return sysfilt_ops[~filt].for_fop; 1156 1157 mtx_lock(&filterops_lock); 1158 sysfilt_ops[~filt].for_refcnt++; 1159 if (sysfilt_ops[~filt].for_fop == NULL) 1160 sysfilt_ops[~filt].for_fop = &null_filtops; 1161 mtx_unlock(&filterops_lock); 1162 1163 return sysfilt_ops[~filt].for_fop; 1164 } 1165 1166 static void 1167 kqueue_fo_release(int filt) 1168 { 1169 1170 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1171 return; 1172 1173 if (sysfilt_ops[~filt].for_nolock) 1174 return; 1175 1176 mtx_lock(&filterops_lock); 1177 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1178 ("filter object refcount not valid on release")); 1179 sysfilt_ops[~filt].for_refcnt--; 1180 mtx_unlock(&filterops_lock); 1181 } 1182 1183 /* 1184 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1185 * influence if memory allocation should wait. Make sure it is 0 if you 1186 * hold any mutexes. 1187 */ 1188 static int 1189 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1190 { 1191 struct filterops *fops; 1192 struct file *fp; 1193 struct knote *kn, *tkn; 1194 struct knlist *knl; 1195 cap_rights_t rights; 1196 int error, filt, event; 1197 int haskqglobal, filedesc_unlock; 1198 1199 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1200 return (EINVAL); 1201 1202 fp = NULL; 1203 kn = NULL; 1204 knl = NULL; 1205 error = 0; 1206 haskqglobal = 0; 1207 filedesc_unlock = 0; 1208 1209 filt = kev->filter; 1210 fops = kqueue_fo_find(filt); 1211 if (fops == NULL) 1212 return EINVAL; 1213 1214 if (kev->flags & EV_ADD) { 1215 /* 1216 * Prevent waiting with locks. Non-sleepable 1217 * allocation failures are handled in the loop, only 1218 * if the spare knote appears to be actually required. 1219 */ 1220 tkn = knote_alloc(waitok); 1221 } else { 1222 tkn = NULL; 1223 } 1224 1225 findkn: 1226 if (fops->f_isfd) { 1227 KASSERT(td != NULL, ("td is NULL")); 1228 if (kev->ident > INT_MAX) 1229 error = EBADF; 1230 else 1231 error = fget(td, kev->ident, 1232 cap_rights_init(&rights, CAP_EVENT), &fp); 1233 if (error) 1234 goto done; 1235 1236 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1237 kev->ident, 0) != 0) { 1238 /* try again */ 1239 fdrop(fp, td); 1240 fp = NULL; 1241 error = kqueue_expand(kq, fops, kev->ident, waitok); 1242 if (error) 1243 goto done; 1244 goto findkn; 1245 } 1246 1247 if (fp->f_type == DTYPE_KQUEUE) { 1248 /* 1249 * If we add some intelligence about what we are doing, 1250 * we should be able to support events on ourselves. 1251 * We need to know when we are doing this to prevent 1252 * getting both the knlist lock and the kq lock since 1253 * they are the same thing. 1254 */ 1255 if (fp->f_data == kq) { 1256 error = EINVAL; 1257 goto done; 1258 } 1259 1260 /* 1261 * Pre-lock the filedesc before the global 1262 * lock mutex, see the comment in 1263 * kqueue_close(). 1264 */ 1265 FILEDESC_XLOCK(td->td_proc->p_fd); 1266 filedesc_unlock = 1; 1267 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1268 } 1269 1270 KQ_LOCK(kq); 1271 if (kev->ident < kq->kq_knlistsize) { 1272 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1273 if (kev->filter == kn->kn_filter) 1274 break; 1275 } 1276 } else { 1277 if ((kev->flags & EV_ADD) == EV_ADD) 1278 kqueue_expand(kq, fops, kev->ident, waitok); 1279 1280 KQ_LOCK(kq); 1281 1282 /* 1283 * If possible, find an existing knote to use for this kevent. 1284 */ 1285 if (kev->filter == EVFILT_PROC && 1286 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1287 /* This is an internal creation of a process tracking 1288 * note. Don't attempt to coalesce this with an 1289 * existing note. 1290 */ 1291 ; 1292 } else if (kq->kq_knhashmask != 0) { 1293 struct klist *list; 1294 1295 list = &kq->kq_knhash[ 1296 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1297 SLIST_FOREACH(kn, list, kn_link) 1298 if (kev->ident == kn->kn_id && 1299 kev->filter == kn->kn_filter) 1300 break; 1301 } 1302 } 1303 1304 /* knote is in the process of changing, wait for it to stabilize. */ 1305 if (kn != NULL && kn_in_flux(kn)) { 1306 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1307 if (filedesc_unlock) { 1308 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1309 filedesc_unlock = 0; 1310 } 1311 kq->kq_state |= KQ_FLUXWAIT; 1312 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1313 if (fp != NULL) { 1314 fdrop(fp, td); 1315 fp = NULL; 1316 } 1317 goto findkn; 1318 } 1319 1320 /* 1321 * kn now contains the matching knote, or NULL if no match 1322 */ 1323 if (kn == NULL) { 1324 if (kev->flags & EV_ADD) { 1325 kn = tkn; 1326 tkn = NULL; 1327 if (kn == NULL) { 1328 KQ_UNLOCK(kq); 1329 error = ENOMEM; 1330 goto done; 1331 } 1332 kn->kn_fp = fp; 1333 kn->kn_kq = kq; 1334 kn->kn_fop = fops; 1335 /* 1336 * apply reference counts to knote structure, and 1337 * do not release it at the end of this routine. 1338 */ 1339 fops = NULL; 1340 fp = NULL; 1341 1342 kn->kn_sfflags = kev->fflags; 1343 kn->kn_sdata = kev->data; 1344 kev->fflags = 0; 1345 kev->data = 0; 1346 kn->kn_kevent = *kev; 1347 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1348 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1349 kn->kn_status = KN_DETACHED; 1350 kn_enter_flux(kn); 1351 1352 error = knote_attach(kn, kq); 1353 KQ_UNLOCK(kq); 1354 if (error != 0) { 1355 tkn = kn; 1356 goto done; 1357 } 1358 1359 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1360 knote_drop_detached(kn, td); 1361 goto done; 1362 } 1363 knl = kn_list_lock(kn); 1364 goto done_ev_add; 1365 } else { 1366 /* No matching knote and the EV_ADD flag is not set. */ 1367 KQ_UNLOCK(kq); 1368 error = ENOENT; 1369 goto done; 1370 } 1371 } 1372 1373 if (kev->flags & EV_DELETE) { 1374 kn_enter_flux(kn); 1375 KQ_UNLOCK(kq); 1376 knote_drop(kn, td); 1377 goto done; 1378 } 1379 1380 if (kev->flags & EV_FORCEONESHOT) { 1381 kn->kn_flags |= EV_ONESHOT; 1382 KNOTE_ACTIVATE(kn, 1); 1383 } 1384 1385 /* 1386 * The user may change some filter values after the initial EV_ADD, 1387 * but doing so will not reset any filter which has already been 1388 * triggered. 1389 */ 1390 kn->kn_status |= KN_SCAN; 1391 kn_enter_flux(kn); 1392 KQ_UNLOCK(kq); 1393 knl = kn_list_lock(kn); 1394 kn->kn_kevent.udata = kev->udata; 1395 if (!fops->f_isfd && fops->f_touch != NULL) { 1396 fops->f_touch(kn, kev, EVENT_REGISTER); 1397 } else { 1398 kn->kn_sfflags = kev->fflags; 1399 kn->kn_sdata = kev->data; 1400 } 1401 1402 /* 1403 * We can get here with kn->kn_knlist == NULL. This can happen when 1404 * the initial attach event decides that the event is "completed" 1405 * already. i.e. filt_procattach is called on a zombie process. It 1406 * will call filt_proc which will remove it from the list, and NULL 1407 * kn_knlist. 1408 */ 1409 done_ev_add: 1410 if ((kev->flags & EV_ENABLE) != 0) 1411 kn->kn_status &= ~KN_DISABLED; 1412 else if ((kev->flags & EV_DISABLE) != 0) 1413 kn->kn_status |= KN_DISABLED; 1414 1415 if ((kn->kn_status & KN_DISABLED) == 0) 1416 event = kn->kn_fop->f_event(kn, 0); 1417 else 1418 event = 0; 1419 1420 KQ_LOCK(kq); 1421 if (event) 1422 kn->kn_status |= KN_ACTIVE; 1423 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1424 KN_ACTIVE) 1425 knote_enqueue(kn); 1426 kn->kn_status &= ~KN_SCAN; 1427 kn_leave_flux(kn); 1428 kn_list_unlock(knl); 1429 KQ_UNLOCK_FLUX(kq); 1430 1431 done: 1432 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1433 if (filedesc_unlock) 1434 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1435 if (fp != NULL) 1436 fdrop(fp, td); 1437 knote_free(tkn); 1438 if (fops != NULL) 1439 kqueue_fo_release(filt); 1440 return (error); 1441 } 1442 1443 static int 1444 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1445 { 1446 int error; 1447 struct kqueue *kq; 1448 1449 error = 0; 1450 1451 kq = fp->f_data; 1452 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1453 return (EBADF); 1454 *kqp = kq; 1455 KQ_LOCK(kq); 1456 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1457 KQ_UNLOCK(kq); 1458 return (EBADF); 1459 } 1460 kq->kq_refcnt++; 1461 KQ_UNLOCK(kq); 1462 1463 return error; 1464 } 1465 1466 static void 1467 kqueue_release(struct kqueue *kq, int locked) 1468 { 1469 if (locked) 1470 KQ_OWNED(kq); 1471 else 1472 KQ_LOCK(kq); 1473 kq->kq_refcnt--; 1474 if (kq->kq_refcnt == 1) 1475 wakeup(&kq->kq_refcnt); 1476 if (!locked) 1477 KQ_UNLOCK(kq); 1478 } 1479 1480 static void 1481 kqueue_schedtask(struct kqueue *kq) 1482 { 1483 1484 KQ_OWNED(kq); 1485 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1486 ("scheduling kqueue task while draining")); 1487 1488 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1489 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1490 kq->kq_state |= KQ_TASKSCHED; 1491 } 1492 } 1493 1494 /* 1495 * Expand the kq to make sure we have storage for fops/ident pair. 1496 * 1497 * Return 0 on success (or no work necessary), return errno on failure. 1498 * 1499 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1500 * If kqueue_register is called from a non-fd context, there usually/should 1501 * be no locks held. 1502 */ 1503 static int 1504 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1505 int waitok) 1506 { 1507 struct klist *list, *tmp_knhash, *to_free; 1508 u_long tmp_knhashmask; 1509 int size; 1510 int fd; 1511 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1512 1513 KQ_NOTOWNED(kq); 1514 1515 to_free = NULL; 1516 if (fops->f_isfd) { 1517 fd = ident; 1518 if (kq->kq_knlistsize <= fd) { 1519 size = kq->kq_knlistsize; 1520 while (size <= fd) 1521 size += KQEXTENT; 1522 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1523 if (list == NULL) 1524 return ENOMEM; 1525 KQ_LOCK(kq); 1526 if (kq->kq_knlistsize > fd) { 1527 to_free = list; 1528 list = NULL; 1529 } else { 1530 if (kq->kq_knlist != NULL) { 1531 bcopy(kq->kq_knlist, list, 1532 kq->kq_knlistsize * sizeof(*list)); 1533 to_free = kq->kq_knlist; 1534 kq->kq_knlist = NULL; 1535 } 1536 bzero((caddr_t)list + 1537 kq->kq_knlistsize * sizeof(*list), 1538 (size - kq->kq_knlistsize) * sizeof(*list)); 1539 kq->kq_knlistsize = size; 1540 kq->kq_knlist = list; 1541 } 1542 KQ_UNLOCK(kq); 1543 } 1544 } else { 1545 if (kq->kq_knhashmask == 0) { 1546 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1547 &tmp_knhashmask); 1548 if (tmp_knhash == NULL) 1549 return ENOMEM; 1550 KQ_LOCK(kq); 1551 if (kq->kq_knhashmask == 0) { 1552 kq->kq_knhash = tmp_knhash; 1553 kq->kq_knhashmask = tmp_knhashmask; 1554 } else { 1555 to_free = tmp_knhash; 1556 } 1557 KQ_UNLOCK(kq); 1558 } 1559 } 1560 free(to_free, M_KQUEUE); 1561 1562 KQ_NOTOWNED(kq); 1563 return 0; 1564 } 1565 1566 static void 1567 kqueue_task(void *arg, int pending) 1568 { 1569 struct kqueue *kq; 1570 int haskqglobal; 1571 1572 haskqglobal = 0; 1573 kq = arg; 1574 1575 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1576 KQ_LOCK(kq); 1577 1578 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1579 1580 kq->kq_state &= ~KQ_TASKSCHED; 1581 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1582 wakeup(&kq->kq_state); 1583 } 1584 KQ_UNLOCK(kq); 1585 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1586 } 1587 1588 /* 1589 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1590 * We treat KN_MARKER knotes as if they are in flux. 1591 */ 1592 static int 1593 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1594 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1595 { 1596 struct kevent *kevp; 1597 struct knote *kn, *marker; 1598 struct knlist *knl; 1599 sbintime_t asbt, rsbt; 1600 int count, error, haskqglobal, influx, nkev, touch; 1601 1602 count = maxevents; 1603 nkev = 0; 1604 error = 0; 1605 haskqglobal = 0; 1606 1607 if (maxevents == 0) 1608 goto done_nl; 1609 1610 rsbt = 0; 1611 if (tsp != NULL) { 1612 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1613 tsp->tv_nsec >= 1000000000) { 1614 error = EINVAL; 1615 goto done_nl; 1616 } 1617 if (timespecisset(tsp)) { 1618 if (tsp->tv_sec <= INT32_MAX) { 1619 rsbt = tstosbt(*tsp); 1620 if (TIMESEL(&asbt, rsbt)) 1621 asbt += tc_tick_sbt; 1622 if (asbt <= SBT_MAX - rsbt) 1623 asbt += rsbt; 1624 else 1625 asbt = 0; 1626 rsbt >>= tc_precexp; 1627 } else 1628 asbt = 0; 1629 } else 1630 asbt = -1; 1631 } else 1632 asbt = 0; 1633 marker = knote_alloc(1); 1634 marker->kn_status = KN_MARKER; 1635 KQ_LOCK(kq); 1636 1637 retry: 1638 kevp = keva; 1639 if (kq->kq_count == 0) { 1640 if (asbt == -1) { 1641 error = EWOULDBLOCK; 1642 } else { 1643 kq->kq_state |= KQ_SLEEP; 1644 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1645 "kqread", asbt, rsbt, C_ABSOLUTE); 1646 } 1647 if (error == 0) 1648 goto retry; 1649 /* don't restart after signals... */ 1650 if (error == ERESTART) 1651 error = EINTR; 1652 else if (error == EWOULDBLOCK) 1653 error = 0; 1654 goto done; 1655 } 1656 1657 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1658 influx = 0; 1659 while (count) { 1660 KQ_OWNED(kq); 1661 kn = TAILQ_FIRST(&kq->kq_head); 1662 1663 if ((kn->kn_status == KN_MARKER && kn != marker) || 1664 kn_in_flux(kn)) { 1665 if (influx) { 1666 influx = 0; 1667 KQ_FLUX_WAKEUP(kq); 1668 } 1669 kq->kq_state |= KQ_FLUXWAIT; 1670 error = msleep(kq, &kq->kq_lock, PSOCK, 1671 "kqflxwt", 0); 1672 continue; 1673 } 1674 1675 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1676 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1677 kn->kn_status &= ~KN_QUEUED; 1678 kq->kq_count--; 1679 continue; 1680 } 1681 if (kn == marker) { 1682 KQ_FLUX_WAKEUP(kq); 1683 if (count == maxevents) 1684 goto retry; 1685 goto done; 1686 } 1687 KASSERT(!kn_in_flux(kn), 1688 ("knote %p is unexpectedly in flux", kn)); 1689 1690 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1691 kn->kn_status &= ~KN_QUEUED; 1692 kn_enter_flux(kn); 1693 kq->kq_count--; 1694 KQ_UNLOCK(kq); 1695 /* 1696 * We don't need to lock the list since we've 1697 * marked it as in flux. 1698 */ 1699 knote_drop(kn, td); 1700 KQ_LOCK(kq); 1701 continue; 1702 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1703 kn->kn_status &= ~KN_QUEUED; 1704 kn_enter_flux(kn); 1705 kq->kq_count--; 1706 KQ_UNLOCK(kq); 1707 /* 1708 * We don't need to lock the list since we've 1709 * marked the knote as being in flux. 1710 */ 1711 *kevp = kn->kn_kevent; 1712 knote_drop(kn, td); 1713 KQ_LOCK(kq); 1714 kn = NULL; 1715 } else { 1716 kn->kn_status |= KN_SCAN; 1717 kn_enter_flux(kn); 1718 KQ_UNLOCK(kq); 1719 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1720 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1721 knl = kn_list_lock(kn); 1722 if (kn->kn_fop->f_event(kn, 0) == 0) { 1723 KQ_LOCK(kq); 1724 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1725 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1726 KN_SCAN); 1727 kn_leave_flux(kn); 1728 kq->kq_count--; 1729 kn_list_unlock(knl); 1730 influx = 1; 1731 continue; 1732 } 1733 touch = (!kn->kn_fop->f_isfd && 1734 kn->kn_fop->f_touch != NULL); 1735 if (touch) 1736 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1737 else 1738 *kevp = kn->kn_kevent; 1739 KQ_LOCK(kq); 1740 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1741 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1742 /* 1743 * Manually clear knotes who weren't 1744 * 'touch'ed. 1745 */ 1746 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1747 kn->kn_data = 0; 1748 kn->kn_fflags = 0; 1749 } 1750 if (kn->kn_flags & EV_DISPATCH) 1751 kn->kn_status |= KN_DISABLED; 1752 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1753 kq->kq_count--; 1754 } else 1755 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1756 1757 kn->kn_status &= ~KN_SCAN; 1758 kn_leave_flux(kn); 1759 kn_list_unlock(knl); 1760 influx = 1; 1761 } 1762 1763 /* we are returning a copy to the user */ 1764 kevp++; 1765 nkev++; 1766 count--; 1767 1768 if (nkev == KQ_NEVENTS) { 1769 influx = 0; 1770 KQ_UNLOCK_FLUX(kq); 1771 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1772 nkev = 0; 1773 kevp = keva; 1774 KQ_LOCK(kq); 1775 if (error) 1776 break; 1777 } 1778 } 1779 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1780 done: 1781 KQ_OWNED(kq); 1782 KQ_UNLOCK_FLUX(kq); 1783 knote_free(marker); 1784 done_nl: 1785 KQ_NOTOWNED(kq); 1786 if (nkev != 0) 1787 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1788 td->td_retval[0] = maxevents - count; 1789 return (error); 1790 } 1791 1792 /*ARGSUSED*/ 1793 static int 1794 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1795 struct ucred *active_cred, struct thread *td) 1796 { 1797 /* 1798 * Enabling sigio causes two major problems: 1799 * 1) infinite recursion: 1800 * Synopsys: kevent is being used to track signals and have FIOASYNC 1801 * set. On receipt of a signal this will cause a kqueue to recurse 1802 * into itself over and over. Sending the sigio causes the kqueue 1803 * to become ready, which in turn posts sigio again, forever. 1804 * Solution: this can be solved by setting a flag in the kqueue that 1805 * we have a SIGIO in progress. 1806 * 2) locking problems: 1807 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1808 * us above the proc and pgrp locks. 1809 * Solution: Post a signal using an async mechanism, being sure to 1810 * record a generation count in the delivery so that we do not deliver 1811 * a signal to the wrong process. 1812 * 1813 * Note, these two mechanisms are somewhat mutually exclusive! 1814 */ 1815 #if 0 1816 struct kqueue *kq; 1817 1818 kq = fp->f_data; 1819 switch (cmd) { 1820 case FIOASYNC: 1821 if (*(int *)data) { 1822 kq->kq_state |= KQ_ASYNC; 1823 } else { 1824 kq->kq_state &= ~KQ_ASYNC; 1825 } 1826 return (0); 1827 1828 case FIOSETOWN: 1829 return (fsetown(*(int *)data, &kq->kq_sigio)); 1830 1831 case FIOGETOWN: 1832 *(int *)data = fgetown(&kq->kq_sigio); 1833 return (0); 1834 } 1835 #endif 1836 1837 return (ENOTTY); 1838 } 1839 1840 /*ARGSUSED*/ 1841 static int 1842 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1843 struct thread *td) 1844 { 1845 struct kqueue *kq; 1846 int revents = 0; 1847 int error; 1848 1849 if ((error = kqueue_acquire(fp, &kq))) 1850 return POLLERR; 1851 1852 KQ_LOCK(kq); 1853 if (events & (POLLIN | POLLRDNORM)) { 1854 if (kq->kq_count) { 1855 revents |= events & (POLLIN | POLLRDNORM); 1856 } else { 1857 selrecord(td, &kq->kq_sel); 1858 if (SEL_WAITING(&kq->kq_sel)) 1859 kq->kq_state |= KQ_SEL; 1860 } 1861 } 1862 kqueue_release(kq, 1); 1863 KQ_UNLOCK(kq); 1864 return (revents); 1865 } 1866 1867 /*ARGSUSED*/ 1868 static int 1869 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1870 struct thread *td) 1871 { 1872 1873 bzero((void *)st, sizeof *st); 1874 /* 1875 * We no longer return kq_count because the unlocked value is useless. 1876 * If you spent all this time getting the count, why not spend your 1877 * syscall better by calling kevent? 1878 * 1879 * XXX - This is needed for libc_r. 1880 */ 1881 st->st_mode = S_IFIFO; 1882 return (0); 1883 } 1884 1885 static void 1886 kqueue_drain(struct kqueue *kq, struct thread *td) 1887 { 1888 struct knote *kn; 1889 int i; 1890 1891 KQ_LOCK(kq); 1892 1893 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1894 ("kqueue already closing")); 1895 kq->kq_state |= KQ_CLOSING; 1896 if (kq->kq_refcnt > 1) 1897 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1898 1899 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1900 1901 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1902 ("kqueue's knlist not empty")); 1903 1904 for (i = 0; i < kq->kq_knlistsize; i++) { 1905 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1906 if (kn_in_flux(kn)) { 1907 kq->kq_state |= KQ_FLUXWAIT; 1908 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1909 continue; 1910 } 1911 kn_enter_flux(kn); 1912 KQ_UNLOCK(kq); 1913 knote_drop(kn, td); 1914 KQ_LOCK(kq); 1915 } 1916 } 1917 if (kq->kq_knhashmask != 0) { 1918 for (i = 0; i <= kq->kq_knhashmask; i++) { 1919 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1920 if (kn_in_flux(kn)) { 1921 kq->kq_state |= KQ_FLUXWAIT; 1922 msleep(kq, &kq->kq_lock, PSOCK, 1923 "kqclo2", 0); 1924 continue; 1925 } 1926 kn_enter_flux(kn); 1927 KQ_UNLOCK(kq); 1928 knote_drop(kn, td); 1929 KQ_LOCK(kq); 1930 } 1931 } 1932 } 1933 1934 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1935 kq->kq_state |= KQ_TASKDRAIN; 1936 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1937 } 1938 1939 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1940 selwakeuppri(&kq->kq_sel, PSOCK); 1941 if (!SEL_WAITING(&kq->kq_sel)) 1942 kq->kq_state &= ~KQ_SEL; 1943 } 1944 1945 KQ_UNLOCK(kq); 1946 } 1947 1948 static void 1949 kqueue_destroy(struct kqueue *kq) 1950 { 1951 1952 KASSERT(kq->kq_fdp == NULL, 1953 ("kqueue still attached to a file descriptor")); 1954 seldrain(&kq->kq_sel); 1955 knlist_destroy(&kq->kq_sel.si_note); 1956 mtx_destroy(&kq->kq_lock); 1957 1958 if (kq->kq_knhash != NULL) 1959 free(kq->kq_knhash, M_KQUEUE); 1960 if (kq->kq_knlist != NULL) 1961 free(kq->kq_knlist, M_KQUEUE); 1962 1963 funsetown(&kq->kq_sigio); 1964 } 1965 1966 /*ARGSUSED*/ 1967 static int 1968 kqueue_close(struct file *fp, struct thread *td) 1969 { 1970 struct kqueue *kq = fp->f_data; 1971 struct filedesc *fdp; 1972 int error; 1973 int filedesc_unlock; 1974 1975 if ((error = kqueue_acquire(fp, &kq))) 1976 return error; 1977 kqueue_drain(kq, td); 1978 1979 /* 1980 * We could be called due to the knote_drop() doing fdrop(), 1981 * called from kqueue_register(). In this case the global 1982 * lock is owned, and filedesc sx is locked before, to not 1983 * take the sleepable lock after non-sleepable. 1984 */ 1985 fdp = kq->kq_fdp; 1986 kq->kq_fdp = NULL; 1987 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1988 FILEDESC_XLOCK(fdp); 1989 filedesc_unlock = 1; 1990 } else 1991 filedesc_unlock = 0; 1992 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1993 if (filedesc_unlock) 1994 FILEDESC_XUNLOCK(fdp); 1995 1996 kqueue_destroy(kq); 1997 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1998 crfree(kq->kq_cred); 1999 free(kq, M_KQUEUE); 2000 fp->f_data = NULL; 2001 2002 return (0); 2003 } 2004 2005 static int 2006 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2007 { 2008 2009 kif->kf_type = KF_TYPE_KQUEUE; 2010 return (0); 2011 } 2012 2013 static void 2014 kqueue_wakeup(struct kqueue *kq) 2015 { 2016 KQ_OWNED(kq); 2017 2018 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2019 kq->kq_state &= ~KQ_SLEEP; 2020 wakeup(kq); 2021 } 2022 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2023 selwakeuppri(&kq->kq_sel, PSOCK); 2024 if (!SEL_WAITING(&kq->kq_sel)) 2025 kq->kq_state &= ~KQ_SEL; 2026 } 2027 if (!knlist_empty(&kq->kq_sel.si_note)) 2028 kqueue_schedtask(kq); 2029 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2030 pgsigio(&kq->kq_sigio, SIGIO, 0); 2031 } 2032 } 2033 2034 /* 2035 * Walk down a list of knotes, activating them if their event has triggered. 2036 * 2037 * There is a possibility to optimize in the case of one kq watching another. 2038 * Instead of scheduling a task to wake it up, you could pass enough state 2039 * down the chain to make up the parent kqueue. Make this code functional 2040 * first. 2041 */ 2042 void 2043 knote(struct knlist *list, long hint, int lockflags) 2044 { 2045 struct kqueue *kq; 2046 struct knote *kn, *tkn; 2047 int error; 2048 2049 if (list == NULL) 2050 return; 2051 2052 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2053 2054 if ((lockflags & KNF_LISTLOCKED) == 0) 2055 list->kl_lock(list->kl_lockarg); 2056 2057 /* 2058 * If we unlock the list lock (and enter influx), we can 2059 * eliminate the kqueue scheduling, but this will introduce 2060 * four lock/unlock's for each knote to test. Also, marker 2061 * would be needed to keep iteration position, since filters 2062 * or other threads could remove events. 2063 */ 2064 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2065 kq = kn->kn_kq; 2066 KQ_LOCK(kq); 2067 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2068 /* 2069 * Do not process the influx notes, except for 2070 * the influx coming from the kq unlock in the 2071 * kqueue_scan(). In the later case, we do 2072 * not interfere with the scan, since the code 2073 * fragment in kqueue_scan() locks the knlist, 2074 * and cannot proceed until we finished. 2075 */ 2076 KQ_UNLOCK(kq); 2077 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2078 kn_enter_flux(kn); 2079 KQ_UNLOCK(kq); 2080 error = kn->kn_fop->f_event(kn, hint); 2081 KQ_LOCK(kq); 2082 kn_leave_flux(kn); 2083 if (error) 2084 KNOTE_ACTIVATE(kn, 1); 2085 KQ_UNLOCK_FLUX(kq); 2086 } else { 2087 kn->kn_status |= KN_HASKQLOCK; 2088 if (kn->kn_fop->f_event(kn, hint)) 2089 KNOTE_ACTIVATE(kn, 1); 2090 kn->kn_status &= ~KN_HASKQLOCK; 2091 KQ_UNLOCK(kq); 2092 } 2093 } 2094 if ((lockflags & KNF_LISTLOCKED) == 0) 2095 list->kl_unlock(list->kl_lockarg); 2096 } 2097 2098 /* 2099 * add a knote to a knlist 2100 */ 2101 void 2102 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2103 { 2104 2105 KNL_ASSERT_LOCK(knl, islocked); 2106 KQ_NOTOWNED(kn->kn_kq); 2107 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2108 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2109 ("knote %p was not detached", kn)); 2110 if (!islocked) 2111 knl->kl_lock(knl->kl_lockarg); 2112 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2113 if (!islocked) 2114 knl->kl_unlock(knl->kl_lockarg); 2115 KQ_LOCK(kn->kn_kq); 2116 kn->kn_knlist = knl; 2117 kn->kn_status &= ~KN_DETACHED; 2118 KQ_UNLOCK(kn->kn_kq); 2119 } 2120 2121 static void 2122 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2123 int kqislocked) 2124 { 2125 2126 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2127 KNL_ASSERT_LOCK(knl, knlislocked); 2128 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2129 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2130 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2131 ("knote %p was already detached", kn)); 2132 if (!knlislocked) 2133 knl->kl_lock(knl->kl_lockarg); 2134 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2135 kn->kn_knlist = NULL; 2136 if (!knlislocked) 2137 kn_list_unlock(knl); 2138 if (!kqislocked) 2139 KQ_LOCK(kn->kn_kq); 2140 kn->kn_status |= KN_DETACHED; 2141 if (!kqislocked) 2142 KQ_UNLOCK(kn->kn_kq); 2143 } 2144 2145 /* 2146 * remove knote from the specified knlist 2147 */ 2148 void 2149 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2150 { 2151 2152 knlist_remove_kq(knl, kn, islocked, 0); 2153 } 2154 2155 int 2156 knlist_empty(struct knlist *knl) 2157 { 2158 2159 KNL_ASSERT_LOCKED(knl); 2160 return (SLIST_EMPTY(&knl->kl_list)); 2161 } 2162 2163 static struct mtx knlist_lock; 2164 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2165 MTX_DEF); 2166 static void knlist_mtx_lock(void *arg); 2167 static void knlist_mtx_unlock(void *arg); 2168 2169 static void 2170 knlist_mtx_lock(void *arg) 2171 { 2172 2173 mtx_lock((struct mtx *)arg); 2174 } 2175 2176 static void 2177 knlist_mtx_unlock(void *arg) 2178 { 2179 2180 mtx_unlock((struct mtx *)arg); 2181 } 2182 2183 static void 2184 knlist_mtx_assert_locked(void *arg) 2185 { 2186 2187 mtx_assert((struct mtx *)arg, MA_OWNED); 2188 } 2189 2190 static void 2191 knlist_mtx_assert_unlocked(void *arg) 2192 { 2193 2194 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2195 } 2196 2197 static void 2198 knlist_rw_rlock(void *arg) 2199 { 2200 2201 rw_rlock((struct rwlock *)arg); 2202 } 2203 2204 static void 2205 knlist_rw_runlock(void *arg) 2206 { 2207 2208 rw_runlock((struct rwlock *)arg); 2209 } 2210 2211 static void 2212 knlist_rw_assert_locked(void *arg) 2213 { 2214 2215 rw_assert((struct rwlock *)arg, RA_LOCKED); 2216 } 2217 2218 static void 2219 knlist_rw_assert_unlocked(void *arg) 2220 { 2221 2222 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2223 } 2224 2225 void 2226 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2227 void (*kl_unlock)(void *), 2228 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2229 { 2230 2231 if (lock == NULL) 2232 knl->kl_lockarg = &knlist_lock; 2233 else 2234 knl->kl_lockarg = lock; 2235 2236 if (kl_lock == NULL) 2237 knl->kl_lock = knlist_mtx_lock; 2238 else 2239 knl->kl_lock = kl_lock; 2240 if (kl_unlock == NULL) 2241 knl->kl_unlock = knlist_mtx_unlock; 2242 else 2243 knl->kl_unlock = kl_unlock; 2244 if (kl_assert_locked == NULL) 2245 knl->kl_assert_locked = knlist_mtx_assert_locked; 2246 else 2247 knl->kl_assert_locked = kl_assert_locked; 2248 if (kl_assert_unlocked == NULL) 2249 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2250 else 2251 knl->kl_assert_unlocked = kl_assert_unlocked; 2252 2253 knl->kl_autodestroy = 0; 2254 SLIST_INIT(&knl->kl_list); 2255 } 2256 2257 void 2258 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2259 { 2260 2261 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2262 } 2263 2264 struct knlist * 2265 knlist_alloc(struct mtx *lock) 2266 { 2267 struct knlist *knl; 2268 2269 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2270 knlist_init_mtx(knl, lock); 2271 return (knl); 2272 } 2273 2274 void 2275 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2276 { 2277 2278 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2279 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2280 } 2281 2282 void 2283 knlist_destroy(struct knlist *knl) 2284 { 2285 2286 KASSERT(KNLIST_EMPTY(knl), 2287 ("destroying knlist %p with knotes on it", knl)); 2288 } 2289 2290 void 2291 knlist_detach(struct knlist *knl) 2292 { 2293 2294 KNL_ASSERT_LOCKED(knl); 2295 knl->kl_autodestroy = 1; 2296 if (knlist_empty(knl)) { 2297 knlist_destroy(knl); 2298 free(knl, M_KQUEUE); 2299 } 2300 } 2301 2302 /* 2303 * Even if we are locked, we may need to drop the lock to allow any influx 2304 * knotes time to "settle". 2305 */ 2306 void 2307 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2308 { 2309 struct knote *kn, *kn2; 2310 struct kqueue *kq; 2311 2312 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2313 if (islocked) 2314 KNL_ASSERT_LOCKED(knl); 2315 else { 2316 KNL_ASSERT_UNLOCKED(knl); 2317 again: /* need to reacquire lock since we have dropped it */ 2318 knl->kl_lock(knl->kl_lockarg); 2319 } 2320 2321 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2322 kq = kn->kn_kq; 2323 KQ_LOCK(kq); 2324 if (kn_in_flux(kn)) { 2325 KQ_UNLOCK(kq); 2326 continue; 2327 } 2328 knlist_remove_kq(knl, kn, 1, 1); 2329 if (killkn) { 2330 kn_enter_flux(kn); 2331 KQ_UNLOCK(kq); 2332 knote_drop_detached(kn, td); 2333 } else { 2334 /* Make sure cleared knotes disappear soon */ 2335 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2336 KQ_UNLOCK(kq); 2337 } 2338 kq = NULL; 2339 } 2340 2341 if (!SLIST_EMPTY(&knl->kl_list)) { 2342 /* there are still in flux knotes remaining */ 2343 kn = SLIST_FIRST(&knl->kl_list); 2344 kq = kn->kn_kq; 2345 KQ_LOCK(kq); 2346 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2347 knl->kl_unlock(knl->kl_lockarg); 2348 kq->kq_state |= KQ_FLUXWAIT; 2349 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2350 kq = NULL; 2351 goto again; 2352 } 2353 2354 if (islocked) 2355 KNL_ASSERT_LOCKED(knl); 2356 else { 2357 knl->kl_unlock(knl->kl_lockarg); 2358 KNL_ASSERT_UNLOCKED(knl); 2359 } 2360 } 2361 2362 /* 2363 * Remove all knotes referencing a specified fd must be called with FILEDESC 2364 * lock. This prevents a race where a new fd comes along and occupies the 2365 * entry and we attach a knote to the fd. 2366 */ 2367 void 2368 knote_fdclose(struct thread *td, int fd) 2369 { 2370 struct filedesc *fdp = td->td_proc->p_fd; 2371 struct kqueue *kq; 2372 struct knote *kn; 2373 int influx; 2374 2375 FILEDESC_XLOCK_ASSERT(fdp); 2376 2377 /* 2378 * We shouldn't have to worry about new kevents appearing on fd 2379 * since filedesc is locked. 2380 */ 2381 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2382 KQ_LOCK(kq); 2383 2384 again: 2385 influx = 0; 2386 while (kq->kq_knlistsize > fd && 2387 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2388 if (kn_in_flux(kn)) { 2389 /* someone else might be waiting on our knote */ 2390 if (influx) 2391 wakeup(kq); 2392 kq->kq_state |= KQ_FLUXWAIT; 2393 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2394 goto again; 2395 } 2396 kn_enter_flux(kn); 2397 KQ_UNLOCK(kq); 2398 influx = 1; 2399 knote_drop(kn, td); 2400 KQ_LOCK(kq); 2401 } 2402 KQ_UNLOCK_FLUX(kq); 2403 } 2404 } 2405 2406 static int 2407 knote_attach(struct knote *kn, struct kqueue *kq) 2408 { 2409 struct klist *list; 2410 2411 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2412 KQ_OWNED(kq); 2413 2414 if (kn->kn_fop->f_isfd) { 2415 if (kn->kn_id >= kq->kq_knlistsize) 2416 return (ENOMEM); 2417 list = &kq->kq_knlist[kn->kn_id]; 2418 } else { 2419 if (kq->kq_knhash == NULL) 2420 return (ENOMEM); 2421 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2422 } 2423 SLIST_INSERT_HEAD(list, kn, kn_link); 2424 return (0); 2425 } 2426 2427 static void 2428 knote_drop(struct knote *kn, struct thread *td) 2429 { 2430 2431 if ((kn->kn_status & KN_DETACHED) == 0) 2432 kn->kn_fop->f_detach(kn); 2433 knote_drop_detached(kn, td); 2434 } 2435 2436 static void 2437 knote_drop_detached(struct knote *kn, struct thread *td) 2438 { 2439 struct kqueue *kq; 2440 struct klist *list; 2441 2442 kq = kn->kn_kq; 2443 2444 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2445 ("knote %p still attached", kn)); 2446 KQ_NOTOWNED(kq); 2447 2448 KQ_LOCK(kq); 2449 KASSERT(kn->kn_influx == 1, 2450 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2451 2452 if (kn->kn_fop->f_isfd) 2453 list = &kq->kq_knlist[kn->kn_id]; 2454 else 2455 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2456 2457 if (!SLIST_EMPTY(list)) 2458 SLIST_REMOVE(list, kn, knote, kn_link); 2459 if (kn->kn_status & KN_QUEUED) 2460 knote_dequeue(kn); 2461 KQ_UNLOCK_FLUX(kq); 2462 2463 if (kn->kn_fop->f_isfd) { 2464 fdrop(kn->kn_fp, td); 2465 kn->kn_fp = NULL; 2466 } 2467 kqueue_fo_release(kn->kn_kevent.filter); 2468 kn->kn_fop = NULL; 2469 knote_free(kn); 2470 } 2471 2472 static void 2473 knote_enqueue(struct knote *kn) 2474 { 2475 struct kqueue *kq = kn->kn_kq; 2476 2477 KQ_OWNED(kn->kn_kq); 2478 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2479 2480 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2481 kn->kn_status |= KN_QUEUED; 2482 kq->kq_count++; 2483 kqueue_wakeup(kq); 2484 } 2485 2486 static void 2487 knote_dequeue(struct knote *kn) 2488 { 2489 struct kqueue *kq = kn->kn_kq; 2490 2491 KQ_OWNED(kn->kn_kq); 2492 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2493 2494 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2495 kn->kn_status &= ~KN_QUEUED; 2496 kq->kq_count--; 2497 } 2498 2499 static void 2500 knote_init(void) 2501 { 2502 2503 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2504 NULL, NULL, UMA_ALIGN_PTR, 0); 2505 } 2506 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2507 2508 static struct knote * 2509 knote_alloc(int waitok) 2510 { 2511 2512 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | 2513 M_ZERO)); 2514 } 2515 2516 static void 2517 knote_free(struct knote *kn) 2518 { 2519 2520 uma_zfree(knote_zone, kn); 2521 } 2522 2523 /* 2524 * Register the kev w/ the kq specified by fd. 2525 */ 2526 int 2527 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2528 { 2529 struct kqueue *kq; 2530 struct file *fp; 2531 cap_rights_t rights; 2532 int error; 2533 2534 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2535 if (error != 0) 2536 return (error); 2537 if ((error = kqueue_acquire(fp, &kq)) != 0) 2538 goto noacquire; 2539 2540 error = kqueue_register(kq, kev, td, waitok); 2541 kqueue_release(kq, 0); 2542 2543 noacquire: 2544 fdrop(fp, td); 2545 return (error); 2546 } 2547