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 #ifdef KTRACE 891 static size_t 892 kev_iovlen(int n, u_int kgio) 893 { 894 895 if (n < 0 || n >= kgio / sizeof(struct kevent)) 896 return (kgio); 897 return (n * sizeof(struct kevent)); 898 } 899 #endif 900 901 #ifndef _SYS_SYSPROTO_H_ 902 struct kevent_args { 903 int fd; 904 const struct kevent *changelist; 905 int nchanges; 906 struct kevent *eventlist; 907 int nevents; 908 const struct timespec *timeout; 909 }; 910 #endif 911 int 912 sys_kevent(struct thread *td, struct kevent_args *uap) 913 { 914 struct timespec ts, *tsp; 915 struct kevent_copyops k_ops = { 916 .arg = uap, 917 .k_copyout = kevent_copyout, 918 .k_copyin = kevent_copyin, 919 }; 920 int error; 921 #ifdef KTRACE 922 struct uio ktruio; 923 struct iovec ktriov; 924 struct uio *ktruioin = NULL; 925 struct uio *ktruioout = NULL; 926 u_int kgio; 927 #endif 928 929 if (uap->timeout != NULL) { 930 error = copyin(uap->timeout, &ts, sizeof(ts)); 931 if (error) 932 return (error); 933 tsp = &ts; 934 } else 935 tsp = NULL; 936 937 #ifdef KTRACE 938 if (KTRPOINT(td, KTR_GENIO)) { 939 kgio = ktr_geniosize; 940 ktriov.iov_base = uap->changelist; 941 ktriov.iov_len = kev_iovlen(uap->nchanges, kgio); 942 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 943 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 944 .uio_td = td }; 945 ktruioin = cloneuio(&ktruio); 946 ktriov.iov_base = uap->eventlist; 947 ktriov.iov_len = kev_iovlen(uap->nevents, kgio); 948 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 949 ktruioout = cloneuio(&ktruio); 950 } 951 #endif 952 953 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 954 &k_ops, tsp); 955 956 #ifdef KTRACE 957 if (ktruioin != NULL) { 958 ktruioin->uio_resid = kev_iovlen(uap->nchanges, kgio); 959 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 960 ktruioout->uio_resid = kev_iovlen(td->td_retval[0], kgio); 961 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 962 } 963 #endif 964 965 return (error); 966 } 967 968 /* 969 * Copy 'count' items into the destination list pointed to by uap->eventlist. 970 */ 971 static int 972 kevent_copyout(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 = copyout(kevp, uap->eventlist, count * sizeof *kevp); 981 if (error == 0) 982 uap->eventlist += count; 983 return (error); 984 } 985 986 /* 987 * Copy 'count' items from the list pointed to by uap->changelist. 988 */ 989 static int 990 kevent_copyin(void *arg, struct kevent *kevp, int count) 991 { 992 struct kevent_args *uap; 993 int error; 994 995 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 996 uap = (struct kevent_args *)arg; 997 998 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 999 if (error == 0) 1000 uap->changelist += count; 1001 return (error); 1002 } 1003 1004 int 1005 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1006 struct kevent_copyops *k_ops, const struct timespec *timeout) 1007 { 1008 cap_rights_t rights; 1009 struct file *fp; 1010 int error; 1011 1012 cap_rights_init(&rights); 1013 if (nchanges > 0) 1014 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 1015 if (nevents > 0) 1016 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 1017 error = fget(td, fd, &rights, &fp); 1018 if (error != 0) 1019 return (error); 1020 1021 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1022 fdrop(fp, td); 1023 1024 return (error); 1025 } 1026 1027 static int 1028 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1029 struct kevent_copyops *k_ops, const struct timespec *timeout) 1030 { 1031 struct kevent keva[KQ_NEVENTS]; 1032 struct kevent *kevp, *changes; 1033 int i, n, nerrors, error; 1034 1035 nerrors = 0; 1036 while (nchanges > 0) { 1037 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1038 error = k_ops->k_copyin(k_ops->arg, keva, n); 1039 if (error) 1040 return (error); 1041 changes = keva; 1042 for (i = 0; i < n; i++) { 1043 kevp = &changes[i]; 1044 if (!kevp->filter) 1045 continue; 1046 kevp->flags &= ~EV_SYSFLAGS; 1047 error = kqueue_register(kq, kevp, td, 1); 1048 if (error || (kevp->flags & EV_RECEIPT)) { 1049 if (nevents == 0) 1050 return (error); 1051 kevp->flags = EV_ERROR; 1052 kevp->data = error; 1053 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1054 nevents--; 1055 nerrors++; 1056 } 1057 } 1058 nchanges -= n; 1059 } 1060 if (nerrors) { 1061 td->td_retval[0] = nerrors; 1062 return (0); 1063 } 1064 1065 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1066 } 1067 1068 int 1069 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1070 struct kevent_copyops *k_ops, const struct timespec *timeout) 1071 { 1072 struct kqueue *kq; 1073 int error; 1074 1075 error = kqueue_acquire(fp, &kq); 1076 if (error != 0) 1077 return (error); 1078 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1079 kqueue_release(kq, 0); 1080 return (error); 1081 } 1082 1083 /* 1084 * Performs a kevent() call on a temporarily created kqueue. This can be 1085 * used to perform one-shot polling, similar to poll() and select(). 1086 */ 1087 int 1088 kern_kevent_anonymous(struct thread *td, int nevents, 1089 struct kevent_copyops *k_ops) 1090 { 1091 struct kqueue kq = {}; 1092 int error; 1093 1094 kqueue_init(&kq); 1095 kq.kq_refcnt = 1; 1096 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1097 kqueue_drain(&kq, td); 1098 kqueue_destroy(&kq); 1099 return (error); 1100 } 1101 1102 int 1103 kqueue_add_filteropts(int filt, struct filterops *filtops) 1104 { 1105 int error; 1106 1107 error = 0; 1108 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1109 printf( 1110 "trying to add a filterop that is out of range: %d is beyond %d\n", 1111 ~filt, EVFILT_SYSCOUNT); 1112 return EINVAL; 1113 } 1114 mtx_lock(&filterops_lock); 1115 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1116 sysfilt_ops[~filt].for_fop != NULL) 1117 error = EEXIST; 1118 else { 1119 sysfilt_ops[~filt].for_fop = filtops; 1120 sysfilt_ops[~filt].for_refcnt = 0; 1121 } 1122 mtx_unlock(&filterops_lock); 1123 1124 return (error); 1125 } 1126 1127 int 1128 kqueue_del_filteropts(int filt) 1129 { 1130 int error; 1131 1132 error = 0; 1133 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1134 return EINVAL; 1135 1136 mtx_lock(&filterops_lock); 1137 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1138 sysfilt_ops[~filt].for_fop == NULL) 1139 error = EINVAL; 1140 else if (sysfilt_ops[~filt].for_refcnt != 0) 1141 error = EBUSY; 1142 else { 1143 sysfilt_ops[~filt].for_fop = &null_filtops; 1144 sysfilt_ops[~filt].for_refcnt = 0; 1145 } 1146 mtx_unlock(&filterops_lock); 1147 1148 return error; 1149 } 1150 1151 static struct filterops * 1152 kqueue_fo_find(int filt) 1153 { 1154 1155 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1156 return NULL; 1157 1158 if (sysfilt_ops[~filt].for_nolock) 1159 return sysfilt_ops[~filt].for_fop; 1160 1161 mtx_lock(&filterops_lock); 1162 sysfilt_ops[~filt].for_refcnt++; 1163 if (sysfilt_ops[~filt].for_fop == NULL) 1164 sysfilt_ops[~filt].for_fop = &null_filtops; 1165 mtx_unlock(&filterops_lock); 1166 1167 return sysfilt_ops[~filt].for_fop; 1168 } 1169 1170 static void 1171 kqueue_fo_release(int filt) 1172 { 1173 1174 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1175 return; 1176 1177 if (sysfilt_ops[~filt].for_nolock) 1178 return; 1179 1180 mtx_lock(&filterops_lock); 1181 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1182 ("filter object refcount not valid on release")); 1183 sysfilt_ops[~filt].for_refcnt--; 1184 mtx_unlock(&filterops_lock); 1185 } 1186 1187 /* 1188 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1189 * influence if memory allocation should wait. Make sure it is 0 if you 1190 * hold any mutexes. 1191 */ 1192 static int 1193 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1194 { 1195 struct filterops *fops; 1196 struct file *fp; 1197 struct knote *kn, *tkn; 1198 struct knlist *knl; 1199 cap_rights_t rights; 1200 int error, filt, event; 1201 int haskqglobal, filedesc_unlock; 1202 1203 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1204 return (EINVAL); 1205 1206 fp = NULL; 1207 kn = NULL; 1208 knl = NULL; 1209 error = 0; 1210 haskqglobal = 0; 1211 filedesc_unlock = 0; 1212 1213 filt = kev->filter; 1214 fops = kqueue_fo_find(filt); 1215 if (fops == NULL) 1216 return EINVAL; 1217 1218 if (kev->flags & EV_ADD) { 1219 /* 1220 * Prevent waiting with locks. Non-sleepable 1221 * allocation failures are handled in the loop, only 1222 * if the spare knote appears to be actually required. 1223 */ 1224 tkn = knote_alloc(waitok); 1225 } else { 1226 tkn = NULL; 1227 } 1228 1229 findkn: 1230 if (fops->f_isfd) { 1231 KASSERT(td != NULL, ("td is NULL")); 1232 if (kev->ident > INT_MAX) 1233 error = EBADF; 1234 else 1235 error = fget(td, kev->ident, 1236 cap_rights_init(&rights, CAP_EVENT), &fp); 1237 if (error) 1238 goto done; 1239 1240 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1241 kev->ident, 0) != 0) { 1242 /* try again */ 1243 fdrop(fp, td); 1244 fp = NULL; 1245 error = kqueue_expand(kq, fops, kev->ident, waitok); 1246 if (error) 1247 goto done; 1248 goto findkn; 1249 } 1250 1251 if (fp->f_type == DTYPE_KQUEUE) { 1252 /* 1253 * If we add some intelligence about what we are doing, 1254 * we should be able to support events on ourselves. 1255 * We need to know when we are doing this to prevent 1256 * getting both the knlist lock and the kq lock since 1257 * they are the same thing. 1258 */ 1259 if (fp->f_data == kq) { 1260 error = EINVAL; 1261 goto done; 1262 } 1263 1264 /* 1265 * Pre-lock the filedesc before the global 1266 * lock mutex, see the comment in 1267 * kqueue_close(). 1268 */ 1269 FILEDESC_XLOCK(td->td_proc->p_fd); 1270 filedesc_unlock = 1; 1271 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1272 } 1273 1274 KQ_LOCK(kq); 1275 if (kev->ident < kq->kq_knlistsize) { 1276 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1277 if (kev->filter == kn->kn_filter) 1278 break; 1279 } 1280 } else { 1281 if ((kev->flags & EV_ADD) == EV_ADD) 1282 kqueue_expand(kq, fops, kev->ident, waitok); 1283 1284 KQ_LOCK(kq); 1285 1286 /* 1287 * If possible, find an existing knote to use for this kevent. 1288 */ 1289 if (kev->filter == EVFILT_PROC && 1290 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1291 /* This is an internal creation of a process tracking 1292 * note. Don't attempt to coalesce this with an 1293 * existing note. 1294 */ 1295 ; 1296 } else if (kq->kq_knhashmask != 0) { 1297 struct klist *list; 1298 1299 list = &kq->kq_knhash[ 1300 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1301 SLIST_FOREACH(kn, list, kn_link) 1302 if (kev->ident == kn->kn_id && 1303 kev->filter == kn->kn_filter) 1304 break; 1305 } 1306 } 1307 1308 /* knote is in the process of changing, wait for it to stabilize. */ 1309 if (kn != NULL && kn_in_flux(kn)) { 1310 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1311 if (filedesc_unlock) { 1312 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1313 filedesc_unlock = 0; 1314 } 1315 kq->kq_state |= KQ_FLUXWAIT; 1316 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1317 if (fp != NULL) { 1318 fdrop(fp, td); 1319 fp = NULL; 1320 } 1321 goto findkn; 1322 } 1323 1324 /* 1325 * kn now contains the matching knote, or NULL if no match 1326 */ 1327 if (kn == NULL) { 1328 if (kev->flags & EV_ADD) { 1329 kn = tkn; 1330 tkn = NULL; 1331 if (kn == NULL) { 1332 KQ_UNLOCK(kq); 1333 error = ENOMEM; 1334 goto done; 1335 } 1336 kn->kn_fp = fp; 1337 kn->kn_kq = kq; 1338 kn->kn_fop = fops; 1339 /* 1340 * apply reference counts to knote structure, and 1341 * do not release it at the end of this routine. 1342 */ 1343 fops = NULL; 1344 fp = NULL; 1345 1346 kn->kn_sfflags = kev->fflags; 1347 kn->kn_sdata = kev->data; 1348 kev->fflags = 0; 1349 kev->data = 0; 1350 kn->kn_kevent = *kev; 1351 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1352 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1353 kn->kn_status = KN_DETACHED; 1354 kn_enter_flux(kn); 1355 1356 error = knote_attach(kn, kq); 1357 KQ_UNLOCK(kq); 1358 if (error != 0) { 1359 tkn = kn; 1360 goto done; 1361 } 1362 1363 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1364 knote_drop_detached(kn, td); 1365 goto done; 1366 } 1367 knl = kn_list_lock(kn); 1368 goto done_ev_add; 1369 } else { 1370 /* No matching knote and the EV_ADD flag is not set. */ 1371 KQ_UNLOCK(kq); 1372 error = ENOENT; 1373 goto done; 1374 } 1375 } 1376 1377 if (kev->flags & EV_DELETE) { 1378 kn_enter_flux(kn); 1379 KQ_UNLOCK(kq); 1380 knote_drop(kn, td); 1381 goto done; 1382 } 1383 1384 if (kev->flags & EV_FORCEONESHOT) { 1385 kn->kn_flags |= EV_ONESHOT; 1386 KNOTE_ACTIVATE(kn, 1); 1387 } 1388 1389 /* 1390 * The user may change some filter values after the initial EV_ADD, 1391 * but doing so will not reset any filter which has already been 1392 * triggered. 1393 */ 1394 kn->kn_status |= KN_SCAN; 1395 kn_enter_flux(kn); 1396 KQ_UNLOCK(kq); 1397 knl = kn_list_lock(kn); 1398 kn->kn_kevent.udata = kev->udata; 1399 if (!fops->f_isfd && fops->f_touch != NULL) { 1400 fops->f_touch(kn, kev, EVENT_REGISTER); 1401 } else { 1402 kn->kn_sfflags = kev->fflags; 1403 kn->kn_sdata = kev->data; 1404 } 1405 1406 /* 1407 * We can get here with kn->kn_knlist == NULL. This can happen when 1408 * the initial attach event decides that the event is "completed" 1409 * already. i.e. filt_procattach is called on a zombie process. It 1410 * will call filt_proc which will remove it from the list, and NULL 1411 * kn_knlist. 1412 */ 1413 done_ev_add: 1414 if ((kev->flags & EV_ENABLE) != 0) 1415 kn->kn_status &= ~KN_DISABLED; 1416 else if ((kev->flags & EV_DISABLE) != 0) 1417 kn->kn_status |= KN_DISABLED; 1418 1419 if ((kn->kn_status & KN_DISABLED) == 0) 1420 event = kn->kn_fop->f_event(kn, 0); 1421 else 1422 event = 0; 1423 1424 KQ_LOCK(kq); 1425 if (event) 1426 kn->kn_status |= KN_ACTIVE; 1427 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1428 KN_ACTIVE) 1429 knote_enqueue(kn); 1430 kn->kn_status &= ~KN_SCAN; 1431 kn_leave_flux(kn); 1432 kn_list_unlock(knl); 1433 KQ_UNLOCK_FLUX(kq); 1434 1435 done: 1436 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1437 if (filedesc_unlock) 1438 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1439 if (fp != NULL) 1440 fdrop(fp, td); 1441 knote_free(tkn); 1442 if (fops != NULL) 1443 kqueue_fo_release(filt); 1444 return (error); 1445 } 1446 1447 static int 1448 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1449 { 1450 int error; 1451 struct kqueue *kq; 1452 1453 error = 0; 1454 1455 kq = fp->f_data; 1456 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1457 return (EBADF); 1458 *kqp = kq; 1459 KQ_LOCK(kq); 1460 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1461 KQ_UNLOCK(kq); 1462 return (EBADF); 1463 } 1464 kq->kq_refcnt++; 1465 KQ_UNLOCK(kq); 1466 1467 return error; 1468 } 1469 1470 static void 1471 kqueue_release(struct kqueue *kq, int locked) 1472 { 1473 if (locked) 1474 KQ_OWNED(kq); 1475 else 1476 KQ_LOCK(kq); 1477 kq->kq_refcnt--; 1478 if (kq->kq_refcnt == 1) 1479 wakeup(&kq->kq_refcnt); 1480 if (!locked) 1481 KQ_UNLOCK(kq); 1482 } 1483 1484 static void 1485 kqueue_schedtask(struct kqueue *kq) 1486 { 1487 1488 KQ_OWNED(kq); 1489 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1490 ("scheduling kqueue task while draining")); 1491 1492 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1493 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1494 kq->kq_state |= KQ_TASKSCHED; 1495 } 1496 } 1497 1498 /* 1499 * Expand the kq to make sure we have storage for fops/ident pair. 1500 * 1501 * Return 0 on success (or no work necessary), return errno on failure. 1502 * 1503 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1504 * If kqueue_register is called from a non-fd context, there usually/should 1505 * be no locks held. 1506 */ 1507 static int 1508 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1509 int waitok) 1510 { 1511 struct klist *list, *tmp_knhash, *to_free; 1512 u_long tmp_knhashmask; 1513 int size; 1514 int fd; 1515 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1516 1517 KQ_NOTOWNED(kq); 1518 1519 to_free = NULL; 1520 if (fops->f_isfd) { 1521 fd = ident; 1522 if (kq->kq_knlistsize <= fd) { 1523 size = kq->kq_knlistsize; 1524 while (size <= fd) 1525 size += KQEXTENT; 1526 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1527 if (list == NULL) 1528 return ENOMEM; 1529 KQ_LOCK(kq); 1530 if (kq->kq_knlistsize > fd) { 1531 to_free = list; 1532 list = NULL; 1533 } else { 1534 if (kq->kq_knlist != NULL) { 1535 bcopy(kq->kq_knlist, list, 1536 kq->kq_knlistsize * sizeof(*list)); 1537 to_free = kq->kq_knlist; 1538 kq->kq_knlist = NULL; 1539 } 1540 bzero((caddr_t)list + 1541 kq->kq_knlistsize * sizeof(*list), 1542 (size - kq->kq_knlistsize) * sizeof(*list)); 1543 kq->kq_knlistsize = size; 1544 kq->kq_knlist = list; 1545 } 1546 KQ_UNLOCK(kq); 1547 } 1548 } else { 1549 if (kq->kq_knhashmask == 0) { 1550 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1551 &tmp_knhashmask); 1552 if (tmp_knhash == NULL) 1553 return ENOMEM; 1554 KQ_LOCK(kq); 1555 if (kq->kq_knhashmask == 0) { 1556 kq->kq_knhash = tmp_knhash; 1557 kq->kq_knhashmask = tmp_knhashmask; 1558 } else { 1559 to_free = tmp_knhash; 1560 } 1561 KQ_UNLOCK(kq); 1562 } 1563 } 1564 free(to_free, M_KQUEUE); 1565 1566 KQ_NOTOWNED(kq); 1567 return 0; 1568 } 1569 1570 static void 1571 kqueue_task(void *arg, int pending) 1572 { 1573 struct kqueue *kq; 1574 int haskqglobal; 1575 1576 haskqglobal = 0; 1577 kq = arg; 1578 1579 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1580 KQ_LOCK(kq); 1581 1582 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1583 1584 kq->kq_state &= ~KQ_TASKSCHED; 1585 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1586 wakeup(&kq->kq_state); 1587 } 1588 KQ_UNLOCK(kq); 1589 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1590 } 1591 1592 /* 1593 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1594 * We treat KN_MARKER knotes as if they are in flux. 1595 */ 1596 static int 1597 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1598 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1599 { 1600 struct kevent *kevp; 1601 struct knote *kn, *marker; 1602 struct knlist *knl; 1603 sbintime_t asbt, rsbt; 1604 int count, error, haskqglobal, influx, nkev, touch; 1605 1606 count = maxevents; 1607 nkev = 0; 1608 error = 0; 1609 haskqglobal = 0; 1610 1611 if (maxevents == 0) 1612 goto done_nl; 1613 1614 rsbt = 0; 1615 if (tsp != NULL) { 1616 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1617 tsp->tv_nsec >= 1000000000) { 1618 error = EINVAL; 1619 goto done_nl; 1620 } 1621 if (timespecisset(tsp)) { 1622 if (tsp->tv_sec <= INT32_MAX) { 1623 rsbt = tstosbt(*tsp); 1624 if (TIMESEL(&asbt, rsbt)) 1625 asbt += tc_tick_sbt; 1626 if (asbt <= SBT_MAX - rsbt) 1627 asbt += rsbt; 1628 else 1629 asbt = 0; 1630 rsbt >>= tc_precexp; 1631 } else 1632 asbt = 0; 1633 } else 1634 asbt = -1; 1635 } else 1636 asbt = 0; 1637 marker = knote_alloc(1); 1638 marker->kn_status = KN_MARKER; 1639 KQ_LOCK(kq); 1640 1641 retry: 1642 kevp = keva; 1643 if (kq->kq_count == 0) { 1644 if (asbt == -1) { 1645 error = EWOULDBLOCK; 1646 } else { 1647 kq->kq_state |= KQ_SLEEP; 1648 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1649 "kqread", asbt, rsbt, C_ABSOLUTE); 1650 } 1651 if (error == 0) 1652 goto retry; 1653 /* don't restart after signals... */ 1654 if (error == ERESTART) 1655 error = EINTR; 1656 else if (error == EWOULDBLOCK) 1657 error = 0; 1658 goto done; 1659 } 1660 1661 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1662 influx = 0; 1663 while (count) { 1664 KQ_OWNED(kq); 1665 kn = TAILQ_FIRST(&kq->kq_head); 1666 1667 if ((kn->kn_status == KN_MARKER && kn != marker) || 1668 kn_in_flux(kn)) { 1669 if (influx) { 1670 influx = 0; 1671 KQ_FLUX_WAKEUP(kq); 1672 } 1673 kq->kq_state |= KQ_FLUXWAIT; 1674 error = msleep(kq, &kq->kq_lock, PSOCK, 1675 "kqflxwt", 0); 1676 continue; 1677 } 1678 1679 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1680 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1681 kn->kn_status &= ~KN_QUEUED; 1682 kq->kq_count--; 1683 continue; 1684 } 1685 if (kn == marker) { 1686 KQ_FLUX_WAKEUP(kq); 1687 if (count == maxevents) 1688 goto retry; 1689 goto done; 1690 } 1691 KASSERT(!kn_in_flux(kn), 1692 ("knote %p is unexpectedly in flux", kn)); 1693 1694 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1695 kn->kn_status &= ~KN_QUEUED; 1696 kn_enter_flux(kn); 1697 kq->kq_count--; 1698 KQ_UNLOCK(kq); 1699 /* 1700 * We don't need to lock the list since we've 1701 * marked it as in flux. 1702 */ 1703 knote_drop(kn, td); 1704 KQ_LOCK(kq); 1705 continue; 1706 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1707 kn->kn_status &= ~KN_QUEUED; 1708 kn_enter_flux(kn); 1709 kq->kq_count--; 1710 KQ_UNLOCK(kq); 1711 /* 1712 * We don't need to lock the list since we've 1713 * marked the knote as being in flux. 1714 */ 1715 *kevp = kn->kn_kevent; 1716 knote_drop(kn, td); 1717 KQ_LOCK(kq); 1718 kn = NULL; 1719 } else { 1720 kn->kn_status |= KN_SCAN; 1721 kn_enter_flux(kn); 1722 KQ_UNLOCK(kq); 1723 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1724 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1725 knl = kn_list_lock(kn); 1726 if (kn->kn_fop->f_event(kn, 0) == 0) { 1727 KQ_LOCK(kq); 1728 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1729 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1730 KN_SCAN); 1731 kn_leave_flux(kn); 1732 kq->kq_count--; 1733 kn_list_unlock(knl); 1734 influx = 1; 1735 continue; 1736 } 1737 touch = (!kn->kn_fop->f_isfd && 1738 kn->kn_fop->f_touch != NULL); 1739 if (touch) 1740 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1741 else 1742 *kevp = kn->kn_kevent; 1743 KQ_LOCK(kq); 1744 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1745 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1746 /* 1747 * Manually clear knotes who weren't 1748 * 'touch'ed. 1749 */ 1750 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1751 kn->kn_data = 0; 1752 kn->kn_fflags = 0; 1753 } 1754 if (kn->kn_flags & EV_DISPATCH) 1755 kn->kn_status |= KN_DISABLED; 1756 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1757 kq->kq_count--; 1758 } else 1759 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1760 1761 kn->kn_status &= ~KN_SCAN; 1762 kn_leave_flux(kn); 1763 kn_list_unlock(knl); 1764 influx = 1; 1765 } 1766 1767 /* we are returning a copy to the user */ 1768 kevp++; 1769 nkev++; 1770 count--; 1771 1772 if (nkev == KQ_NEVENTS) { 1773 influx = 0; 1774 KQ_UNLOCK_FLUX(kq); 1775 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1776 nkev = 0; 1777 kevp = keva; 1778 KQ_LOCK(kq); 1779 if (error) 1780 break; 1781 } 1782 } 1783 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1784 done: 1785 KQ_OWNED(kq); 1786 KQ_UNLOCK_FLUX(kq); 1787 knote_free(marker); 1788 done_nl: 1789 KQ_NOTOWNED(kq); 1790 if (nkev != 0) 1791 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1792 td->td_retval[0] = maxevents - count; 1793 return (error); 1794 } 1795 1796 /*ARGSUSED*/ 1797 static int 1798 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1799 struct ucred *active_cred, struct thread *td) 1800 { 1801 /* 1802 * Enabling sigio causes two major problems: 1803 * 1) infinite recursion: 1804 * Synopsys: kevent is being used to track signals and have FIOASYNC 1805 * set. On receipt of a signal this will cause a kqueue to recurse 1806 * into itself over and over. Sending the sigio causes the kqueue 1807 * to become ready, which in turn posts sigio again, forever. 1808 * Solution: this can be solved by setting a flag in the kqueue that 1809 * we have a SIGIO in progress. 1810 * 2) locking problems: 1811 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1812 * us above the proc and pgrp locks. 1813 * Solution: Post a signal using an async mechanism, being sure to 1814 * record a generation count in the delivery so that we do not deliver 1815 * a signal to the wrong process. 1816 * 1817 * Note, these two mechanisms are somewhat mutually exclusive! 1818 */ 1819 #if 0 1820 struct kqueue *kq; 1821 1822 kq = fp->f_data; 1823 switch (cmd) { 1824 case FIOASYNC: 1825 if (*(int *)data) { 1826 kq->kq_state |= KQ_ASYNC; 1827 } else { 1828 kq->kq_state &= ~KQ_ASYNC; 1829 } 1830 return (0); 1831 1832 case FIOSETOWN: 1833 return (fsetown(*(int *)data, &kq->kq_sigio)); 1834 1835 case FIOGETOWN: 1836 *(int *)data = fgetown(&kq->kq_sigio); 1837 return (0); 1838 } 1839 #endif 1840 1841 return (ENOTTY); 1842 } 1843 1844 /*ARGSUSED*/ 1845 static int 1846 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1847 struct thread *td) 1848 { 1849 struct kqueue *kq; 1850 int revents = 0; 1851 int error; 1852 1853 if ((error = kqueue_acquire(fp, &kq))) 1854 return POLLERR; 1855 1856 KQ_LOCK(kq); 1857 if (events & (POLLIN | POLLRDNORM)) { 1858 if (kq->kq_count) { 1859 revents |= events & (POLLIN | POLLRDNORM); 1860 } else { 1861 selrecord(td, &kq->kq_sel); 1862 if (SEL_WAITING(&kq->kq_sel)) 1863 kq->kq_state |= KQ_SEL; 1864 } 1865 } 1866 kqueue_release(kq, 1); 1867 KQ_UNLOCK(kq); 1868 return (revents); 1869 } 1870 1871 /*ARGSUSED*/ 1872 static int 1873 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1874 struct thread *td) 1875 { 1876 1877 bzero((void *)st, sizeof *st); 1878 /* 1879 * We no longer return kq_count because the unlocked value is useless. 1880 * If you spent all this time getting the count, why not spend your 1881 * syscall better by calling kevent? 1882 * 1883 * XXX - This is needed for libc_r. 1884 */ 1885 st->st_mode = S_IFIFO; 1886 return (0); 1887 } 1888 1889 static void 1890 kqueue_drain(struct kqueue *kq, struct thread *td) 1891 { 1892 struct knote *kn; 1893 int i; 1894 1895 KQ_LOCK(kq); 1896 1897 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1898 ("kqueue already closing")); 1899 kq->kq_state |= KQ_CLOSING; 1900 if (kq->kq_refcnt > 1) 1901 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1902 1903 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1904 1905 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1906 ("kqueue's knlist not empty")); 1907 1908 for (i = 0; i < kq->kq_knlistsize; i++) { 1909 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1910 if (kn_in_flux(kn)) { 1911 kq->kq_state |= KQ_FLUXWAIT; 1912 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1913 continue; 1914 } 1915 kn_enter_flux(kn); 1916 KQ_UNLOCK(kq); 1917 knote_drop(kn, td); 1918 KQ_LOCK(kq); 1919 } 1920 } 1921 if (kq->kq_knhashmask != 0) { 1922 for (i = 0; i <= kq->kq_knhashmask; i++) { 1923 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1924 if (kn_in_flux(kn)) { 1925 kq->kq_state |= KQ_FLUXWAIT; 1926 msleep(kq, &kq->kq_lock, PSOCK, 1927 "kqclo2", 0); 1928 continue; 1929 } 1930 kn_enter_flux(kn); 1931 KQ_UNLOCK(kq); 1932 knote_drop(kn, td); 1933 KQ_LOCK(kq); 1934 } 1935 } 1936 } 1937 1938 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1939 kq->kq_state |= KQ_TASKDRAIN; 1940 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1941 } 1942 1943 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1944 selwakeuppri(&kq->kq_sel, PSOCK); 1945 if (!SEL_WAITING(&kq->kq_sel)) 1946 kq->kq_state &= ~KQ_SEL; 1947 } 1948 1949 KQ_UNLOCK(kq); 1950 } 1951 1952 static void 1953 kqueue_destroy(struct kqueue *kq) 1954 { 1955 1956 KASSERT(kq->kq_fdp == NULL, 1957 ("kqueue still attached to a file descriptor")); 1958 seldrain(&kq->kq_sel); 1959 knlist_destroy(&kq->kq_sel.si_note); 1960 mtx_destroy(&kq->kq_lock); 1961 1962 if (kq->kq_knhash != NULL) 1963 free(kq->kq_knhash, M_KQUEUE); 1964 if (kq->kq_knlist != NULL) 1965 free(kq->kq_knlist, M_KQUEUE); 1966 1967 funsetown(&kq->kq_sigio); 1968 } 1969 1970 /*ARGSUSED*/ 1971 static int 1972 kqueue_close(struct file *fp, struct thread *td) 1973 { 1974 struct kqueue *kq = fp->f_data; 1975 struct filedesc *fdp; 1976 int error; 1977 int filedesc_unlock; 1978 1979 if ((error = kqueue_acquire(fp, &kq))) 1980 return error; 1981 kqueue_drain(kq, td); 1982 1983 /* 1984 * We could be called due to the knote_drop() doing fdrop(), 1985 * called from kqueue_register(). In this case the global 1986 * lock is owned, and filedesc sx is locked before, to not 1987 * take the sleepable lock after non-sleepable. 1988 */ 1989 fdp = kq->kq_fdp; 1990 kq->kq_fdp = NULL; 1991 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1992 FILEDESC_XLOCK(fdp); 1993 filedesc_unlock = 1; 1994 } else 1995 filedesc_unlock = 0; 1996 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1997 if (filedesc_unlock) 1998 FILEDESC_XUNLOCK(fdp); 1999 2000 kqueue_destroy(kq); 2001 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 2002 crfree(kq->kq_cred); 2003 free(kq, M_KQUEUE); 2004 fp->f_data = NULL; 2005 2006 return (0); 2007 } 2008 2009 static int 2010 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2011 { 2012 2013 kif->kf_type = KF_TYPE_KQUEUE; 2014 return (0); 2015 } 2016 2017 static void 2018 kqueue_wakeup(struct kqueue *kq) 2019 { 2020 KQ_OWNED(kq); 2021 2022 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2023 kq->kq_state &= ~KQ_SLEEP; 2024 wakeup(kq); 2025 } 2026 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2027 selwakeuppri(&kq->kq_sel, PSOCK); 2028 if (!SEL_WAITING(&kq->kq_sel)) 2029 kq->kq_state &= ~KQ_SEL; 2030 } 2031 if (!knlist_empty(&kq->kq_sel.si_note)) 2032 kqueue_schedtask(kq); 2033 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2034 pgsigio(&kq->kq_sigio, SIGIO, 0); 2035 } 2036 } 2037 2038 /* 2039 * Walk down a list of knotes, activating them if their event has triggered. 2040 * 2041 * There is a possibility to optimize in the case of one kq watching another. 2042 * Instead of scheduling a task to wake it up, you could pass enough state 2043 * down the chain to make up the parent kqueue. Make this code functional 2044 * first. 2045 */ 2046 void 2047 knote(struct knlist *list, long hint, int lockflags) 2048 { 2049 struct kqueue *kq; 2050 struct knote *kn, *tkn; 2051 int error; 2052 2053 if (list == NULL) 2054 return; 2055 2056 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2057 2058 if ((lockflags & KNF_LISTLOCKED) == 0) 2059 list->kl_lock(list->kl_lockarg); 2060 2061 /* 2062 * If we unlock the list lock (and enter influx), we can 2063 * eliminate the kqueue scheduling, but this will introduce 2064 * four lock/unlock's for each knote to test. Also, marker 2065 * would be needed to keep iteration position, since filters 2066 * or other threads could remove events. 2067 */ 2068 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2069 kq = kn->kn_kq; 2070 KQ_LOCK(kq); 2071 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2072 /* 2073 * Do not process the influx notes, except for 2074 * the influx coming from the kq unlock in the 2075 * kqueue_scan(). In the later case, we do 2076 * not interfere with the scan, since the code 2077 * fragment in kqueue_scan() locks the knlist, 2078 * and cannot proceed until we finished. 2079 */ 2080 KQ_UNLOCK(kq); 2081 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2082 kn_enter_flux(kn); 2083 KQ_UNLOCK(kq); 2084 error = kn->kn_fop->f_event(kn, hint); 2085 KQ_LOCK(kq); 2086 kn_leave_flux(kn); 2087 if (error) 2088 KNOTE_ACTIVATE(kn, 1); 2089 KQ_UNLOCK_FLUX(kq); 2090 } else { 2091 kn->kn_status |= KN_HASKQLOCK; 2092 if (kn->kn_fop->f_event(kn, hint)) 2093 KNOTE_ACTIVATE(kn, 1); 2094 kn->kn_status &= ~KN_HASKQLOCK; 2095 KQ_UNLOCK(kq); 2096 } 2097 } 2098 if ((lockflags & KNF_LISTLOCKED) == 0) 2099 list->kl_unlock(list->kl_lockarg); 2100 } 2101 2102 /* 2103 * add a knote to a knlist 2104 */ 2105 void 2106 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2107 { 2108 2109 KNL_ASSERT_LOCK(knl, islocked); 2110 KQ_NOTOWNED(kn->kn_kq); 2111 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2112 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2113 ("knote %p was not detached", kn)); 2114 if (!islocked) 2115 knl->kl_lock(knl->kl_lockarg); 2116 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2117 if (!islocked) 2118 knl->kl_unlock(knl->kl_lockarg); 2119 KQ_LOCK(kn->kn_kq); 2120 kn->kn_knlist = knl; 2121 kn->kn_status &= ~KN_DETACHED; 2122 KQ_UNLOCK(kn->kn_kq); 2123 } 2124 2125 static void 2126 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2127 int kqislocked) 2128 { 2129 2130 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2131 KNL_ASSERT_LOCK(knl, knlislocked); 2132 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2133 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2134 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2135 ("knote %p was already detached", kn)); 2136 if (!knlislocked) 2137 knl->kl_lock(knl->kl_lockarg); 2138 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2139 kn->kn_knlist = NULL; 2140 if (!knlislocked) 2141 kn_list_unlock(knl); 2142 if (!kqislocked) 2143 KQ_LOCK(kn->kn_kq); 2144 kn->kn_status |= KN_DETACHED; 2145 if (!kqislocked) 2146 KQ_UNLOCK(kn->kn_kq); 2147 } 2148 2149 /* 2150 * remove knote from the specified knlist 2151 */ 2152 void 2153 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2154 { 2155 2156 knlist_remove_kq(knl, kn, islocked, 0); 2157 } 2158 2159 int 2160 knlist_empty(struct knlist *knl) 2161 { 2162 2163 KNL_ASSERT_LOCKED(knl); 2164 return (SLIST_EMPTY(&knl->kl_list)); 2165 } 2166 2167 static struct mtx knlist_lock; 2168 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2169 MTX_DEF); 2170 static void knlist_mtx_lock(void *arg); 2171 static void knlist_mtx_unlock(void *arg); 2172 2173 static void 2174 knlist_mtx_lock(void *arg) 2175 { 2176 2177 mtx_lock((struct mtx *)arg); 2178 } 2179 2180 static void 2181 knlist_mtx_unlock(void *arg) 2182 { 2183 2184 mtx_unlock((struct mtx *)arg); 2185 } 2186 2187 static void 2188 knlist_mtx_assert_locked(void *arg) 2189 { 2190 2191 mtx_assert((struct mtx *)arg, MA_OWNED); 2192 } 2193 2194 static void 2195 knlist_mtx_assert_unlocked(void *arg) 2196 { 2197 2198 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2199 } 2200 2201 static void 2202 knlist_rw_rlock(void *arg) 2203 { 2204 2205 rw_rlock((struct rwlock *)arg); 2206 } 2207 2208 static void 2209 knlist_rw_runlock(void *arg) 2210 { 2211 2212 rw_runlock((struct rwlock *)arg); 2213 } 2214 2215 static void 2216 knlist_rw_assert_locked(void *arg) 2217 { 2218 2219 rw_assert((struct rwlock *)arg, RA_LOCKED); 2220 } 2221 2222 static void 2223 knlist_rw_assert_unlocked(void *arg) 2224 { 2225 2226 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2227 } 2228 2229 void 2230 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2231 void (*kl_unlock)(void *), 2232 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2233 { 2234 2235 if (lock == NULL) 2236 knl->kl_lockarg = &knlist_lock; 2237 else 2238 knl->kl_lockarg = lock; 2239 2240 if (kl_lock == NULL) 2241 knl->kl_lock = knlist_mtx_lock; 2242 else 2243 knl->kl_lock = kl_lock; 2244 if (kl_unlock == NULL) 2245 knl->kl_unlock = knlist_mtx_unlock; 2246 else 2247 knl->kl_unlock = kl_unlock; 2248 if (kl_assert_locked == NULL) 2249 knl->kl_assert_locked = knlist_mtx_assert_locked; 2250 else 2251 knl->kl_assert_locked = kl_assert_locked; 2252 if (kl_assert_unlocked == NULL) 2253 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2254 else 2255 knl->kl_assert_unlocked = kl_assert_unlocked; 2256 2257 knl->kl_autodestroy = 0; 2258 SLIST_INIT(&knl->kl_list); 2259 } 2260 2261 void 2262 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2263 { 2264 2265 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2266 } 2267 2268 struct knlist * 2269 knlist_alloc(struct mtx *lock) 2270 { 2271 struct knlist *knl; 2272 2273 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2274 knlist_init_mtx(knl, lock); 2275 return (knl); 2276 } 2277 2278 void 2279 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2280 { 2281 2282 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2283 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2284 } 2285 2286 void 2287 knlist_destroy(struct knlist *knl) 2288 { 2289 2290 KASSERT(KNLIST_EMPTY(knl), 2291 ("destroying knlist %p with knotes on it", knl)); 2292 } 2293 2294 void 2295 knlist_detach(struct knlist *knl) 2296 { 2297 2298 KNL_ASSERT_LOCKED(knl); 2299 knl->kl_autodestroy = 1; 2300 if (knlist_empty(knl)) { 2301 knlist_destroy(knl); 2302 free(knl, M_KQUEUE); 2303 } 2304 } 2305 2306 /* 2307 * Even if we are locked, we may need to drop the lock to allow any influx 2308 * knotes time to "settle". 2309 */ 2310 void 2311 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2312 { 2313 struct knote *kn, *kn2; 2314 struct kqueue *kq; 2315 2316 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2317 if (islocked) 2318 KNL_ASSERT_LOCKED(knl); 2319 else { 2320 KNL_ASSERT_UNLOCKED(knl); 2321 again: /* need to reacquire lock since we have dropped it */ 2322 knl->kl_lock(knl->kl_lockarg); 2323 } 2324 2325 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2326 kq = kn->kn_kq; 2327 KQ_LOCK(kq); 2328 if (kn_in_flux(kn)) { 2329 KQ_UNLOCK(kq); 2330 continue; 2331 } 2332 knlist_remove_kq(knl, kn, 1, 1); 2333 if (killkn) { 2334 kn_enter_flux(kn); 2335 KQ_UNLOCK(kq); 2336 knote_drop_detached(kn, td); 2337 } else { 2338 /* Make sure cleared knotes disappear soon */ 2339 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2340 KQ_UNLOCK(kq); 2341 } 2342 kq = NULL; 2343 } 2344 2345 if (!SLIST_EMPTY(&knl->kl_list)) { 2346 /* there are still in flux knotes remaining */ 2347 kn = SLIST_FIRST(&knl->kl_list); 2348 kq = kn->kn_kq; 2349 KQ_LOCK(kq); 2350 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2351 knl->kl_unlock(knl->kl_lockarg); 2352 kq->kq_state |= KQ_FLUXWAIT; 2353 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2354 kq = NULL; 2355 goto again; 2356 } 2357 2358 if (islocked) 2359 KNL_ASSERT_LOCKED(knl); 2360 else { 2361 knl->kl_unlock(knl->kl_lockarg); 2362 KNL_ASSERT_UNLOCKED(knl); 2363 } 2364 } 2365 2366 /* 2367 * Remove all knotes referencing a specified fd must be called with FILEDESC 2368 * lock. This prevents a race where a new fd comes along and occupies the 2369 * entry and we attach a knote to the fd. 2370 */ 2371 void 2372 knote_fdclose(struct thread *td, int fd) 2373 { 2374 struct filedesc *fdp = td->td_proc->p_fd; 2375 struct kqueue *kq; 2376 struct knote *kn; 2377 int influx; 2378 2379 FILEDESC_XLOCK_ASSERT(fdp); 2380 2381 /* 2382 * We shouldn't have to worry about new kevents appearing on fd 2383 * since filedesc is locked. 2384 */ 2385 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2386 KQ_LOCK(kq); 2387 2388 again: 2389 influx = 0; 2390 while (kq->kq_knlistsize > fd && 2391 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2392 if (kn_in_flux(kn)) { 2393 /* someone else might be waiting on our knote */ 2394 if (influx) 2395 wakeup(kq); 2396 kq->kq_state |= KQ_FLUXWAIT; 2397 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2398 goto again; 2399 } 2400 kn_enter_flux(kn); 2401 KQ_UNLOCK(kq); 2402 influx = 1; 2403 knote_drop(kn, td); 2404 KQ_LOCK(kq); 2405 } 2406 KQ_UNLOCK_FLUX(kq); 2407 } 2408 } 2409 2410 static int 2411 knote_attach(struct knote *kn, struct kqueue *kq) 2412 { 2413 struct klist *list; 2414 2415 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2416 KQ_OWNED(kq); 2417 2418 if (kn->kn_fop->f_isfd) { 2419 if (kn->kn_id >= kq->kq_knlistsize) 2420 return (ENOMEM); 2421 list = &kq->kq_knlist[kn->kn_id]; 2422 } else { 2423 if (kq->kq_knhash == NULL) 2424 return (ENOMEM); 2425 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2426 } 2427 SLIST_INSERT_HEAD(list, kn, kn_link); 2428 return (0); 2429 } 2430 2431 static void 2432 knote_drop(struct knote *kn, struct thread *td) 2433 { 2434 2435 if ((kn->kn_status & KN_DETACHED) == 0) 2436 kn->kn_fop->f_detach(kn); 2437 knote_drop_detached(kn, td); 2438 } 2439 2440 static void 2441 knote_drop_detached(struct knote *kn, struct thread *td) 2442 { 2443 struct kqueue *kq; 2444 struct klist *list; 2445 2446 kq = kn->kn_kq; 2447 2448 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2449 ("knote %p still attached", kn)); 2450 KQ_NOTOWNED(kq); 2451 2452 KQ_LOCK(kq); 2453 KASSERT(kn->kn_influx == 1, 2454 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2455 2456 if (kn->kn_fop->f_isfd) 2457 list = &kq->kq_knlist[kn->kn_id]; 2458 else 2459 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2460 2461 if (!SLIST_EMPTY(list)) 2462 SLIST_REMOVE(list, kn, knote, kn_link); 2463 if (kn->kn_status & KN_QUEUED) 2464 knote_dequeue(kn); 2465 KQ_UNLOCK_FLUX(kq); 2466 2467 if (kn->kn_fop->f_isfd) { 2468 fdrop(kn->kn_fp, td); 2469 kn->kn_fp = NULL; 2470 } 2471 kqueue_fo_release(kn->kn_kevent.filter); 2472 kn->kn_fop = NULL; 2473 knote_free(kn); 2474 } 2475 2476 static void 2477 knote_enqueue(struct knote *kn) 2478 { 2479 struct kqueue *kq = kn->kn_kq; 2480 2481 KQ_OWNED(kn->kn_kq); 2482 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2483 2484 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2485 kn->kn_status |= KN_QUEUED; 2486 kq->kq_count++; 2487 kqueue_wakeup(kq); 2488 } 2489 2490 static void 2491 knote_dequeue(struct knote *kn) 2492 { 2493 struct kqueue *kq = kn->kn_kq; 2494 2495 KQ_OWNED(kn->kn_kq); 2496 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2497 2498 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2499 kn->kn_status &= ~KN_QUEUED; 2500 kq->kq_count--; 2501 } 2502 2503 static void 2504 knote_init(void) 2505 { 2506 2507 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2508 NULL, NULL, UMA_ALIGN_PTR, 0); 2509 } 2510 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2511 2512 static struct knote * 2513 knote_alloc(int waitok) 2514 { 2515 2516 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | 2517 M_ZERO)); 2518 } 2519 2520 static void 2521 knote_free(struct knote *kn) 2522 { 2523 2524 uma_zfree(knote_zone, kn); 2525 } 2526 2527 /* 2528 * Register the kev w/ the kq specified by fd. 2529 */ 2530 int 2531 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2532 { 2533 struct kqueue *kq; 2534 struct file *fp; 2535 cap_rights_t rights; 2536 int error; 2537 2538 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2539 if (error != 0) 2540 return (error); 2541 if ((error = kqueue_acquire(fp, &kq)) != 0) 2542 goto noacquire; 2543 2544 error = kqueue_register(kq, kev, td, waitok); 2545 kqueue_release(kq, 0); 2546 2547 noacquire: 2548 fdrop(fp, td); 2549 return (error); 2550 } 2551