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