1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 5 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 6 * Copyright (c) 2009 Apple, Inc. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include "opt_ktrace.h" 35 #include "opt_kqueue.h" 36 37 #ifdef COMPAT_FREEBSD11 38 #define _WANT_FREEBSD11_KEVENT 39 #endif 40 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/capsicum.h> 44 #include <sys/kernel.h> 45 #include <sys/lock.h> 46 #include <sys/mutex.h> 47 #include <sys/rwlock.h> 48 #include <sys/proc.h> 49 #include <sys/malloc.h> 50 #include <sys/unistd.h> 51 #include <sys/file.h> 52 #include <sys/filedesc.h> 53 #include <sys/filio.h> 54 #include <sys/fcntl.h> 55 #include <sys/kthread.h> 56 #include <sys/selinfo.h> 57 #include <sys/queue.h> 58 #include <sys/event.h> 59 #include <sys/eventvar.h> 60 #include <sys/poll.h> 61 #include <sys/protosw.h> 62 #include <sys/resourcevar.h> 63 #include <sys/sigio.h> 64 #include <sys/signalvar.h> 65 #include <sys/socket.h> 66 #include <sys/socketvar.h> 67 #include <sys/stat.h> 68 #include <sys/sysctl.h> 69 #include <sys/sysproto.h> 70 #include <sys/syscallsubr.h> 71 #include <sys/taskqueue.h> 72 #include <sys/uio.h> 73 #include <sys/user.h> 74 #ifdef KTRACE 75 #include <sys/ktrace.h> 76 #endif 77 #include <machine/atomic.h> 78 79 #include <vm/uma.h> 80 81 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 82 83 /* 84 * This lock is used if multiple kq locks are required. This possibly 85 * should be made into a per proc lock. 86 */ 87 static struct mtx kq_global; 88 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 89 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 90 if (!haslck) \ 91 mtx_lock(lck); \ 92 haslck = 1; \ 93 } while (0) 94 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 95 if (haslck) \ 96 mtx_unlock(lck); \ 97 haslck = 0; \ 98 } while (0) 99 100 TASKQUEUE_DEFINE_THREAD(kqueue_ctx); 101 102 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 103 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 104 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 105 struct thread *td, int waitok); 106 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 107 static void kqueue_release(struct kqueue *kq, int locked); 108 static void kqueue_destroy(struct kqueue *kq); 109 static void kqueue_drain(struct kqueue *kq, struct thread *td); 110 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 111 uintptr_t ident, int waitok); 112 static void kqueue_task(void *arg, int pending); 113 static int kqueue_scan(struct kqueue *kq, int maxevents, 114 struct kevent_copyops *k_ops, 115 const struct timespec *timeout, 116 struct kevent *keva, struct thread *td); 117 static void kqueue_wakeup(struct kqueue *kq); 118 static struct filterops *kqueue_fo_find(int filt); 119 static void kqueue_fo_release(int filt); 120 struct g_kevent_args; 121 static int kern_kevent_generic(struct thread *td, 122 struct g_kevent_args *uap, 123 struct kevent_copyops *k_ops, const char *struct_name); 124 125 static fo_ioctl_t kqueue_ioctl; 126 static fo_poll_t kqueue_poll; 127 static fo_kqfilter_t kqueue_kqfilter; 128 static fo_stat_t kqueue_stat; 129 static fo_close_t kqueue_close; 130 static fo_fill_kinfo_t kqueue_fill_kinfo; 131 132 static struct fileops kqueueops = { 133 .fo_read = invfo_rdwr, 134 .fo_write = invfo_rdwr, 135 .fo_truncate = invfo_truncate, 136 .fo_ioctl = kqueue_ioctl, 137 .fo_poll = kqueue_poll, 138 .fo_kqfilter = kqueue_kqfilter, 139 .fo_stat = kqueue_stat, 140 .fo_close = kqueue_close, 141 .fo_chmod = invfo_chmod, 142 .fo_chown = invfo_chown, 143 .fo_sendfile = invfo_sendfile, 144 .fo_fill_kinfo = kqueue_fill_kinfo, 145 }; 146 147 static int knote_attach(struct knote *kn, struct kqueue *kq); 148 static void knote_drop(struct knote *kn, struct thread *td); 149 static void knote_drop_detached(struct knote *kn, struct thread *td); 150 static void knote_enqueue(struct knote *kn); 151 static void knote_dequeue(struct knote *kn); 152 static void knote_init(void); 153 static struct knote *knote_alloc(int waitok); 154 static void knote_free(struct knote *kn); 155 156 static void filt_kqdetach(struct knote *kn); 157 static int filt_kqueue(struct knote *kn, long hint); 158 static int filt_procattach(struct knote *kn); 159 static void filt_procdetach(struct knote *kn); 160 static int filt_proc(struct knote *kn, long hint); 161 static int filt_fileattach(struct knote *kn); 162 static void filt_timerexpire(void *knx); 163 static int filt_timerattach(struct knote *kn); 164 static void filt_timerdetach(struct knote *kn); 165 static int filt_timer(struct knote *kn, long hint); 166 static int filt_userattach(struct knote *kn); 167 static void filt_userdetach(struct knote *kn); 168 static int filt_user(struct knote *kn, long hint); 169 static void filt_usertouch(struct knote *kn, struct kevent *kev, 170 u_long type); 171 172 static struct filterops file_filtops = { 173 .f_isfd = 1, 174 .f_attach = filt_fileattach, 175 }; 176 static struct filterops kqread_filtops = { 177 .f_isfd = 1, 178 .f_detach = filt_kqdetach, 179 .f_event = filt_kqueue, 180 }; 181 /* XXX - move to kern_proc.c? */ 182 static struct filterops proc_filtops = { 183 .f_isfd = 0, 184 .f_attach = filt_procattach, 185 .f_detach = filt_procdetach, 186 .f_event = filt_proc, 187 }; 188 static struct filterops timer_filtops = { 189 .f_isfd = 0, 190 .f_attach = filt_timerattach, 191 .f_detach = filt_timerdetach, 192 .f_event = filt_timer, 193 }; 194 static struct filterops user_filtops = { 195 .f_attach = filt_userattach, 196 .f_detach = filt_userdetach, 197 .f_event = filt_user, 198 .f_touch = filt_usertouch, 199 }; 200 201 static uma_zone_t knote_zone; 202 static unsigned int kq_ncallouts = 0; 203 static unsigned int kq_calloutmax = 4 * 1024; 204 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 205 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 206 207 /* XXX - ensure not influx ? */ 208 #define KNOTE_ACTIVATE(kn, islock) do { \ 209 if ((islock)) \ 210 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 211 else \ 212 KQ_LOCK((kn)->kn_kq); \ 213 (kn)->kn_status |= KN_ACTIVE; \ 214 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 215 knote_enqueue((kn)); \ 216 if (!(islock)) \ 217 KQ_UNLOCK((kn)->kn_kq); \ 218 } while(0) 219 #define KQ_LOCK(kq) do { \ 220 mtx_lock(&(kq)->kq_lock); \ 221 } while (0) 222 #define KQ_FLUX_WAKEUP(kq) do { \ 223 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 224 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 225 wakeup((kq)); \ 226 } \ 227 } while (0) 228 #define KQ_UNLOCK_FLUX(kq) do { \ 229 KQ_FLUX_WAKEUP(kq); \ 230 mtx_unlock(&(kq)->kq_lock); \ 231 } while (0) 232 #define KQ_UNLOCK(kq) do { \ 233 mtx_unlock(&(kq)->kq_lock); \ 234 } while (0) 235 #define KQ_OWNED(kq) do { \ 236 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 237 } while (0) 238 #define KQ_NOTOWNED(kq) do { \ 239 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 240 } while (0) 241 242 static struct knlist * 243 kn_list_lock(struct knote *kn) 244 { 245 struct knlist *knl; 246 247 knl = kn->kn_knlist; 248 if (knl != NULL) 249 knl->kl_lock(knl->kl_lockarg); 250 return (knl); 251 } 252 253 static void 254 kn_list_unlock(struct knlist *knl) 255 { 256 bool do_free; 257 258 if (knl == NULL) 259 return; 260 do_free = knl->kl_autodestroy && knlist_empty(knl); 261 knl->kl_unlock(knl->kl_lockarg); 262 if (do_free) { 263 knlist_destroy(knl); 264 free(knl, M_KQUEUE); 265 } 266 } 267 268 static bool 269 kn_in_flux(struct knote *kn) 270 { 271 272 return (kn->kn_influx > 0); 273 } 274 275 static void 276 kn_enter_flux(struct knote *kn) 277 { 278 279 KQ_OWNED(kn->kn_kq); 280 MPASS(kn->kn_influx < INT_MAX); 281 kn->kn_influx++; 282 } 283 284 static bool 285 kn_leave_flux(struct knote *kn) 286 { 287 288 KQ_OWNED(kn->kn_kq); 289 MPASS(kn->kn_influx > 0); 290 kn->kn_influx--; 291 return (kn->kn_influx == 0); 292 } 293 294 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 295 if (islocked) \ 296 KNL_ASSERT_LOCKED(knl); \ 297 else \ 298 KNL_ASSERT_UNLOCKED(knl); \ 299 } while (0) 300 #ifdef INVARIANTS 301 #define KNL_ASSERT_LOCKED(knl) do { \ 302 knl->kl_assert_locked((knl)->kl_lockarg); \ 303 } while (0) 304 #define KNL_ASSERT_UNLOCKED(knl) do { \ 305 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 306 } while (0) 307 #else /* !INVARIANTS */ 308 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 309 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 310 #endif /* INVARIANTS */ 311 312 #ifndef KN_HASHSIZE 313 #define KN_HASHSIZE 64 /* XXX should be tunable */ 314 #endif 315 316 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 317 318 static int 319 filt_nullattach(struct knote *kn) 320 { 321 322 return (ENXIO); 323 }; 324 325 struct filterops null_filtops = { 326 .f_isfd = 0, 327 .f_attach = filt_nullattach, 328 }; 329 330 /* XXX - make SYSINIT to add these, and move into respective modules. */ 331 extern struct filterops sig_filtops; 332 extern struct filterops fs_filtops; 333 334 /* 335 * Table for for all system-defined filters. 336 */ 337 static struct mtx filterops_lock; 338 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 339 MTX_DEF); 340 static struct { 341 struct filterops *for_fop; 342 int for_nolock; 343 int for_refcnt; 344 } sysfilt_ops[EVFILT_SYSCOUNT] = { 345 { &file_filtops, 1 }, /* EVFILT_READ */ 346 { &file_filtops, 1 }, /* EVFILT_WRITE */ 347 { &null_filtops }, /* EVFILT_AIO */ 348 { &file_filtops, 1 }, /* EVFILT_VNODE */ 349 { &proc_filtops, 1 }, /* EVFILT_PROC */ 350 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 351 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 352 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 353 { &fs_filtops, 1 }, /* EVFILT_FS */ 354 { &null_filtops }, /* EVFILT_LIO */ 355 { &user_filtops, 1 }, /* EVFILT_USER */ 356 { &null_filtops }, /* EVFILT_SENDFILE */ 357 { &file_filtops, 1 }, /* EVFILT_EMPTY */ 358 }; 359 360 /* 361 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 362 * method. 363 */ 364 static int 365 filt_fileattach(struct knote *kn) 366 { 367 368 return (fo_kqfilter(kn->kn_fp, kn)); 369 } 370 371 /*ARGSUSED*/ 372 static int 373 kqueue_kqfilter(struct file *fp, struct knote *kn) 374 { 375 struct kqueue *kq = kn->kn_fp->f_data; 376 377 if (kn->kn_filter != EVFILT_READ) 378 return (EINVAL); 379 380 kn->kn_status |= KN_KQUEUE; 381 kn->kn_fop = &kqread_filtops; 382 knlist_add(&kq->kq_sel.si_note, kn, 0); 383 384 return (0); 385 } 386 387 static void 388 filt_kqdetach(struct knote *kn) 389 { 390 struct kqueue *kq = kn->kn_fp->f_data; 391 392 knlist_remove(&kq->kq_sel.si_note, kn, 0); 393 } 394 395 /*ARGSUSED*/ 396 static int 397 filt_kqueue(struct knote *kn, long hint) 398 { 399 struct kqueue *kq = kn->kn_fp->f_data; 400 401 kn->kn_data = kq->kq_count; 402 return (kn->kn_data > 0); 403 } 404 405 /* XXX - move to kern_proc.c? */ 406 static int 407 filt_procattach(struct knote *kn) 408 { 409 struct proc *p; 410 int error; 411 bool exiting, immediate; 412 413 exiting = immediate = false; 414 if (kn->kn_sfflags & NOTE_EXIT) 415 p = pfind_any(kn->kn_id); 416 else 417 p = pfind(kn->kn_id); 418 if (p == NULL) 419 return (ESRCH); 420 if (p->p_flag & P_WEXIT) 421 exiting = true; 422 423 if ((error = p_cansee(curthread, p))) { 424 PROC_UNLOCK(p); 425 return (error); 426 } 427 428 kn->kn_ptr.p_proc = p; 429 kn->kn_flags |= EV_CLEAR; /* automatically set */ 430 431 /* 432 * Internal flag indicating registration done by kernel for the 433 * purposes of getting a NOTE_CHILD notification. 434 */ 435 if (kn->kn_flags & EV_FLAG2) { 436 kn->kn_flags &= ~EV_FLAG2; 437 kn->kn_data = kn->kn_sdata; /* ppid */ 438 kn->kn_fflags = NOTE_CHILD; 439 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK); 440 immediate = true; /* Force immediate activation of child note. */ 441 } 442 /* 443 * Internal flag indicating registration done by kernel (for other than 444 * NOTE_CHILD). 445 */ 446 if (kn->kn_flags & EV_FLAG1) { 447 kn->kn_flags &= ~EV_FLAG1; 448 } 449 450 knlist_add(p->p_klist, kn, 1); 451 452 /* 453 * Immediately activate any child notes or, in the case of a zombie 454 * target process, exit notes. The latter is necessary to handle the 455 * case where the target process, e.g. a child, dies before the kevent 456 * is registered. 457 */ 458 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT))) 459 KNOTE_ACTIVATE(kn, 0); 460 461 PROC_UNLOCK(p); 462 463 return (0); 464 } 465 466 /* 467 * The knote may be attached to a different process, which may exit, 468 * leaving nothing for the knote to be attached to. So when the process 469 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 470 * it will be deleted when read out. However, as part of the knote deletion, 471 * this routine is called, so a check is needed to avoid actually performing 472 * a detach, because the original process does not exist any more. 473 */ 474 /* XXX - move to kern_proc.c? */ 475 static void 476 filt_procdetach(struct knote *kn) 477 { 478 479 knlist_remove(kn->kn_knlist, kn, 0); 480 kn->kn_ptr.p_proc = NULL; 481 } 482 483 /* XXX - move to kern_proc.c? */ 484 static int 485 filt_proc(struct knote *kn, long hint) 486 { 487 struct proc *p; 488 u_int event; 489 490 p = kn->kn_ptr.p_proc; 491 if (p == NULL) /* already activated, from attach filter */ 492 return (0); 493 494 /* Mask off extra data. */ 495 event = (u_int)hint & NOTE_PCTRLMASK; 496 497 /* If the user is interested in this event, record it. */ 498 if (kn->kn_sfflags & event) 499 kn->kn_fflags |= event; 500 501 /* Process is gone, so flag the event as finished. */ 502 if (event == NOTE_EXIT) { 503 kn->kn_flags |= EV_EOF | EV_ONESHOT; 504 kn->kn_ptr.p_proc = NULL; 505 if (kn->kn_fflags & NOTE_EXIT) 506 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 507 if (kn->kn_fflags == 0) 508 kn->kn_flags |= EV_DROP; 509 return (1); 510 } 511 512 return (kn->kn_fflags != 0); 513 } 514 515 /* 516 * Called when the process forked. It mostly does the same as the 517 * knote(), activating all knotes registered to be activated when the 518 * process forked. Additionally, for each knote attached to the 519 * parent, check whether user wants to track the new process. If so 520 * attach a new knote to it, and immediately report an event with the 521 * child's pid. 522 */ 523 void 524 knote_fork(struct knlist *list, int pid) 525 { 526 struct kqueue *kq; 527 struct knote *kn; 528 struct kevent kev; 529 int error; 530 531 if (list == NULL) 532 return; 533 list->kl_lock(list->kl_lockarg); 534 535 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 536 kq = kn->kn_kq; 537 KQ_LOCK(kq); 538 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 539 KQ_UNLOCK(kq); 540 continue; 541 } 542 543 /* 544 * The same as knote(), activate the event. 545 */ 546 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 547 kn->kn_status |= KN_HASKQLOCK; 548 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 549 KNOTE_ACTIVATE(kn, 1); 550 kn->kn_status &= ~KN_HASKQLOCK; 551 KQ_UNLOCK(kq); 552 continue; 553 } 554 555 /* 556 * The NOTE_TRACK case. In addition to the activation 557 * of the event, we need to register new events to 558 * track the child. Drop the locks in preparation for 559 * the call to kqueue_register(). 560 */ 561 kn_enter_flux(kn); 562 KQ_UNLOCK(kq); 563 list->kl_unlock(list->kl_lockarg); 564 565 /* 566 * Activate existing knote and register tracking knotes with 567 * new process. 568 * 569 * First register a knote to get just the child notice. This 570 * must be a separate note from a potential NOTE_EXIT 571 * notification since both NOTE_CHILD and NOTE_EXIT are defined 572 * to use the data field (in conflicting ways). 573 */ 574 kev.ident = pid; 575 kev.filter = kn->kn_filter; 576 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | 577 EV_FLAG2; 578 kev.fflags = kn->kn_sfflags; 579 kev.data = kn->kn_id; /* parent */ 580 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 581 error = kqueue_register(kq, &kev, NULL, 0); 582 if (error) 583 kn->kn_fflags |= NOTE_TRACKERR; 584 585 /* 586 * Then register another knote to track other potential events 587 * from the new process. 588 */ 589 kev.ident = pid; 590 kev.filter = kn->kn_filter; 591 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 592 kev.fflags = kn->kn_sfflags; 593 kev.data = kn->kn_id; /* parent */ 594 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 595 error = kqueue_register(kq, &kev, NULL, 0); 596 if (error) 597 kn->kn_fflags |= NOTE_TRACKERR; 598 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 599 KNOTE_ACTIVATE(kn, 0); 600 KQ_LOCK(kq); 601 kn_leave_flux(kn); 602 KQ_UNLOCK_FLUX(kq); 603 list->kl_lock(list->kl_lockarg); 604 } 605 list->kl_unlock(list->kl_lockarg); 606 } 607 608 /* 609 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 610 * interval timer support code. 611 */ 612 613 #define NOTE_TIMER_PRECMASK \ 614 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS) 615 616 static sbintime_t 617 timer2sbintime(intptr_t data, int flags) 618 { 619 int64_t secs; 620 621 /* 622 * Macros for converting to the fractional second portion of an 623 * sbintime_t using 64bit multiplication to improve precision. 624 */ 625 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 626 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 627 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 628 switch (flags & NOTE_TIMER_PRECMASK) { 629 case NOTE_SECONDS: 630 #ifdef __LP64__ 631 if (data > (SBT_MAX / SBT_1S)) 632 return (SBT_MAX); 633 #endif 634 return ((sbintime_t)data << 32); 635 case NOTE_MSECONDS: /* FALLTHROUGH */ 636 case 0: 637 if (data >= 1000) { 638 secs = data / 1000; 639 #ifdef __LP64__ 640 if (secs > (SBT_MAX / SBT_1S)) 641 return (SBT_MAX); 642 #endif 643 return (secs << 32 | MS_TO_SBT(data % 1000)); 644 } 645 return (MS_TO_SBT(data)); 646 case NOTE_USECONDS: 647 if (data >= 1000000) { 648 secs = data / 1000000; 649 #ifdef __LP64__ 650 if (secs > (SBT_MAX / SBT_1S)) 651 return (SBT_MAX); 652 #endif 653 return (secs << 32 | US_TO_SBT(data % 1000000)); 654 } 655 return (US_TO_SBT(data)); 656 case NOTE_NSECONDS: 657 if (data >= 1000000000) { 658 secs = data / 1000000000; 659 #ifdef __LP64__ 660 if (secs > (SBT_MAX / SBT_1S)) 661 return (SBT_MAX); 662 #endif 663 return (secs << 32 | US_TO_SBT(data % 1000000000)); 664 } 665 return (NS_TO_SBT(data)); 666 default: 667 break; 668 } 669 return (-1); 670 } 671 672 struct kq_timer_cb_data { 673 struct callout c; 674 sbintime_t next; /* next timer event fires at */ 675 sbintime_t to; /* precalculated timer period, 0 for abs */ 676 }; 677 678 static void 679 filt_timerexpire(void *knx) 680 { 681 struct knote *kn; 682 struct kq_timer_cb_data *kc; 683 684 kn = knx; 685 kn->kn_data++; 686 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 687 688 if ((kn->kn_flags & EV_ONESHOT) != 0) 689 return; 690 kc = kn->kn_ptr.p_v; 691 if (kc->to == 0) 692 return; 693 kc->next += kc->to; 694 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 695 PCPU_GET(cpuid), C_ABSOLUTE); 696 } 697 698 /* 699 * data contains amount of time to sleep 700 */ 701 static int 702 filt_timerattach(struct knote *kn) 703 { 704 struct kq_timer_cb_data *kc; 705 struct bintime bt; 706 sbintime_t to, sbt; 707 unsigned int ncallouts; 708 709 if (kn->kn_sdata < 0) 710 return (EINVAL); 711 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 712 kn->kn_sdata = 1; 713 /* Only precision unit are supported in flags so far */ 714 if ((kn->kn_sfflags & ~(NOTE_TIMER_PRECMASK | NOTE_ABSTIME)) != 0) 715 return (EINVAL); 716 717 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 718 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 719 getboottimebin(&bt); 720 sbt = bttosbt(bt); 721 to -= sbt; 722 } 723 if (to < 0) 724 return (EINVAL); 725 726 do { 727 ncallouts = kq_ncallouts; 728 if (ncallouts >= kq_calloutmax) 729 return (ENOMEM); 730 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 731 732 if ((kn->kn_sfflags & NOTE_ABSTIME) == 0) 733 kn->kn_flags |= EV_CLEAR; /* automatically set */ 734 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 735 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 736 callout_init(&kc->c, 1); 737 if ((kn->kn_sfflags & NOTE_ABSTIME) != 0) { 738 kc->next = to; 739 kc->to = 0; 740 } else { 741 kc->next = to + sbinuptime(); 742 kc->to = to; 743 } 744 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 745 PCPU_GET(cpuid), C_ABSOLUTE); 746 747 return (0); 748 } 749 750 static void 751 filt_timerdetach(struct knote *kn) 752 { 753 struct kq_timer_cb_data *kc; 754 unsigned int old; 755 756 kc = kn->kn_ptr.p_v; 757 callout_drain(&kc->c); 758 free(kc, M_KQUEUE); 759 old = atomic_fetchadd_int(&kq_ncallouts, -1); 760 KASSERT(old > 0, ("Number of callouts cannot become negative")); 761 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 762 } 763 764 static int 765 filt_timer(struct knote *kn, long hint) 766 { 767 768 return (kn->kn_data != 0); 769 } 770 771 static int 772 filt_userattach(struct knote *kn) 773 { 774 775 /* 776 * EVFILT_USER knotes are not attached to anything in the kernel. 777 */ 778 kn->kn_hook = NULL; 779 if (kn->kn_fflags & NOTE_TRIGGER) 780 kn->kn_hookid = 1; 781 else 782 kn->kn_hookid = 0; 783 return (0); 784 } 785 786 static void 787 filt_userdetach(__unused struct knote *kn) 788 { 789 790 /* 791 * EVFILT_USER knotes are not attached to anything in the kernel. 792 */ 793 } 794 795 static int 796 filt_user(struct knote *kn, __unused long hint) 797 { 798 799 return (kn->kn_hookid); 800 } 801 802 static void 803 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 804 { 805 u_int ffctrl; 806 807 switch (type) { 808 case EVENT_REGISTER: 809 if (kev->fflags & NOTE_TRIGGER) 810 kn->kn_hookid = 1; 811 812 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 813 kev->fflags &= NOTE_FFLAGSMASK; 814 switch (ffctrl) { 815 case NOTE_FFNOP: 816 break; 817 818 case NOTE_FFAND: 819 kn->kn_sfflags &= kev->fflags; 820 break; 821 822 case NOTE_FFOR: 823 kn->kn_sfflags |= kev->fflags; 824 break; 825 826 case NOTE_FFCOPY: 827 kn->kn_sfflags = kev->fflags; 828 break; 829 830 default: 831 /* XXX Return error? */ 832 break; 833 } 834 kn->kn_sdata = kev->data; 835 if (kev->flags & EV_CLEAR) { 836 kn->kn_hookid = 0; 837 kn->kn_data = 0; 838 kn->kn_fflags = 0; 839 } 840 break; 841 842 case EVENT_PROCESS: 843 *kev = kn->kn_kevent; 844 kev->fflags = kn->kn_sfflags; 845 kev->data = kn->kn_sdata; 846 if (kn->kn_flags & EV_CLEAR) { 847 kn->kn_hookid = 0; 848 kn->kn_data = 0; 849 kn->kn_fflags = 0; 850 } 851 break; 852 853 default: 854 panic("filt_usertouch() - invalid type (%ld)", type); 855 break; 856 } 857 } 858 859 int 860 sys_kqueue(struct thread *td, struct kqueue_args *uap) 861 { 862 863 return (kern_kqueue(td, 0, NULL)); 864 } 865 866 static void 867 kqueue_init(struct kqueue *kq) 868 { 869 870 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 871 TAILQ_INIT(&kq->kq_head); 872 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 873 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 874 } 875 876 int 877 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 878 { 879 struct filedesc *fdp; 880 struct kqueue *kq; 881 struct file *fp; 882 struct ucred *cred; 883 int fd, error; 884 885 fdp = td->td_proc->p_fd; 886 cred = td->td_ucred; 887 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 888 return (ENOMEM); 889 890 error = falloc_caps(td, &fp, &fd, flags, fcaps); 891 if (error != 0) { 892 chgkqcnt(cred->cr_ruidinfo, -1, 0); 893 return (error); 894 } 895 896 /* An extra reference on `fp' has been held for us by falloc(). */ 897 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 898 kqueue_init(kq); 899 kq->kq_fdp = fdp; 900 kq->kq_cred = crhold(cred); 901 902 FILEDESC_XLOCK(fdp); 903 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 904 FILEDESC_XUNLOCK(fdp); 905 906 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 907 fdrop(fp, td); 908 909 td->td_retval[0] = fd; 910 return (0); 911 } 912 913 struct g_kevent_args { 914 int fd; 915 void *changelist; 916 int nchanges; 917 void *eventlist; 918 int nevents; 919 const struct timespec *timeout; 920 }; 921 922 int 923 sys_kevent(struct thread *td, struct kevent_args *uap) 924 { 925 struct kevent_copyops k_ops = { 926 .arg = uap, 927 .k_copyout = kevent_copyout, 928 .k_copyin = kevent_copyin, 929 .kevent_size = sizeof(struct kevent), 930 }; 931 struct g_kevent_args gk_args = { 932 .fd = uap->fd, 933 .changelist = uap->changelist, 934 .nchanges = uap->nchanges, 935 .eventlist = uap->eventlist, 936 .nevents = uap->nevents, 937 .timeout = uap->timeout, 938 }; 939 940 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent")); 941 } 942 943 static int 944 kern_kevent_generic(struct thread *td, struct g_kevent_args *uap, 945 struct kevent_copyops *k_ops, const char *struct_name) 946 { 947 struct timespec ts, *tsp; 948 #ifdef KTRACE 949 struct kevent *eventlist = uap->eventlist; 950 #endif 951 int error; 952 953 if (uap->timeout != NULL) { 954 error = copyin(uap->timeout, &ts, sizeof(ts)); 955 if (error) 956 return (error); 957 tsp = &ts; 958 } else 959 tsp = NULL; 960 961 #ifdef KTRACE 962 if (KTRPOINT(td, KTR_STRUCT_ARRAY)) 963 ktrstructarray(struct_name, UIO_USERSPACE, uap->changelist, 964 uap->nchanges, k_ops->kevent_size); 965 #endif 966 967 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 968 k_ops, tsp); 969 970 #ifdef KTRACE 971 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY)) 972 ktrstructarray(struct_name, UIO_USERSPACE, eventlist, 973 td->td_retval[0], k_ops->kevent_size); 974 #endif 975 976 return (error); 977 } 978 979 /* 980 * Copy 'count' items into the destination list pointed to by uap->eventlist. 981 */ 982 static int 983 kevent_copyout(void *arg, struct kevent *kevp, int count) 984 { 985 struct kevent_args *uap; 986 int error; 987 988 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 989 uap = (struct kevent_args *)arg; 990 991 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 992 if (error == 0) 993 uap->eventlist += count; 994 return (error); 995 } 996 997 /* 998 * Copy 'count' items from the list pointed to by uap->changelist. 999 */ 1000 static int 1001 kevent_copyin(void *arg, struct kevent *kevp, int count) 1002 { 1003 struct kevent_args *uap; 1004 int error; 1005 1006 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1007 uap = (struct kevent_args *)arg; 1008 1009 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 1010 if (error == 0) 1011 uap->changelist += count; 1012 return (error); 1013 } 1014 1015 #ifdef COMPAT_FREEBSD11 1016 static int 1017 kevent11_copyout(void *arg, struct kevent *kevp, int count) 1018 { 1019 struct freebsd11_kevent_args *uap; 1020 struct kevent_freebsd11 kev11; 1021 int error, i; 1022 1023 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1024 uap = (struct freebsd11_kevent_args *)arg; 1025 1026 for (i = 0; i < count; i++) { 1027 kev11.ident = kevp->ident; 1028 kev11.filter = kevp->filter; 1029 kev11.flags = kevp->flags; 1030 kev11.fflags = kevp->fflags; 1031 kev11.data = kevp->data; 1032 kev11.udata = kevp->udata; 1033 error = copyout(&kev11, uap->eventlist, sizeof(kev11)); 1034 if (error != 0) 1035 break; 1036 uap->eventlist++; 1037 kevp++; 1038 } 1039 return (error); 1040 } 1041 1042 /* 1043 * Copy 'count' items from the list pointed to by uap->changelist. 1044 */ 1045 static int 1046 kevent11_copyin(void *arg, struct kevent *kevp, int count) 1047 { 1048 struct freebsd11_kevent_args *uap; 1049 struct kevent_freebsd11 kev11; 1050 int error, i; 1051 1052 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 1053 uap = (struct freebsd11_kevent_args *)arg; 1054 1055 for (i = 0; i < count; i++) { 1056 error = copyin(uap->changelist, &kev11, sizeof(kev11)); 1057 if (error != 0) 1058 break; 1059 kevp->ident = kev11.ident; 1060 kevp->filter = kev11.filter; 1061 kevp->flags = kev11.flags; 1062 kevp->fflags = kev11.fflags; 1063 kevp->data = (uintptr_t)kev11.data; 1064 kevp->udata = kev11.udata; 1065 bzero(&kevp->ext, sizeof(kevp->ext)); 1066 uap->changelist++; 1067 kevp++; 1068 } 1069 return (error); 1070 } 1071 1072 int 1073 freebsd11_kevent(struct thread *td, struct freebsd11_kevent_args *uap) 1074 { 1075 struct kevent_copyops k_ops = { 1076 .arg = uap, 1077 .k_copyout = kevent11_copyout, 1078 .k_copyin = kevent11_copyin, 1079 .kevent_size = sizeof(struct kevent_freebsd11), 1080 }; 1081 struct g_kevent_args gk_args = { 1082 .fd = uap->fd, 1083 .changelist = uap->changelist, 1084 .nchanges = uap->nchanges, 1085 .eventlist = uap->eventlist, 1086 .nevents = uap->nevents, 1087 .timeout = uap->timeout, 1088 }; 1089 1090 return (kern_kevent_generic(td, &gk_args, &k_ops, "kevent_freebsd11")); 1091 } 1092 #endif 1093 1094 int 1095 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 1096 struct kevent_copyops *k_ops, const struct timespec *timeout) 1097 { 1098 cap_rights_t rights; 1099 struct file *fp; 1100 int error; 1101 1102 cap_rights_init(&rights); 1103 if (nchanges > 0) 1104 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 1105 if (nevents > 0) 1106 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 1107 error = fget(td, fd, &rights, &fp); 1108 if (error != 0) 1109 return (error); 1110 1111 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1112 fdrop(fp, td); 1113 1114 return (error); 1115 } 1116 1117 static int 1118 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1119 struct kevent_copyops *k_ops, const struct timespec *timeout) 1120 { 1121 struct kevent keva[KQ_NEVENTS]; 1122 struct kevent *kevp, *changes; 1123 int i, n, nerrors, error; 1124 1125 nerrors = 0; 1126 while (nchanges > 0) { 1127 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1128 error = k_ops->k_copyin(k_ops->arg, keva, n); 1129 if (error) 1130 return (error); 1131 changes = keva; 1132 for (i = 0; i < n; i++) { 1133 kevp = &changes[i]; 1134 if (!kevp->filter) 1135 continue; 1136 kevp->flags &= ~EV_SYSFLAGS; 1137 error = kqueue_register(kq, kevp, td, 1); 1138 if (error || (kevp->flags & EV_RECEIPT)) { 1139 if (nevents == 0) 1140 return (error); 1141 kevp->flags = EV_ERROR; 1142 kevp->data = error; 1143 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1144 nevents--; 1145 nerrors++; 1146 } 1147 } 1148 nchanges -= n; 1149 } 1150 if (nerrors) { 1151 td->td_retval[0] = nerrors; 1152 return (0); 1153 } 1154 1155 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1156 } 1157 1158 int 1159 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1160 struct kevent_copyops *k_ops, const struct timespec *timeout) 1161 { 1162 struct kqueue *kq; 1163 int error; 1164 1165 error = kqueue_acquire(fp, &kq); 1166 if (error != 0) 1167 return (error); 1168 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1169 kqueue_release(kq, 0); 1170 return (error); 1171 } 1172 1173 /* 1174 * Performs a kevent() call on a temporarily created kqueue. This can be 1175 * used to perform one-shot polling, similar to poll() and select(). 1176 */ 1177 int 1178 kern_kevent_anonymous(struct thread *td, int nevents, 1179 struct kevent_copyops *k_ops) 1180 { 1181 struct kqueue kq = {}; 1182 int error; 1183 1184 kqueue_init(&kq); 1185 kq.kq_refcnt = 1; 1186 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1187 kqueue_drain(&kq, td); 1188 kqueue_destroy(&kq); 1189 return (error); 1190 } 1191 1192 int 1193 kqueue_add_filteropts(int filt, struct filterops *filtops) 1194 { 1195 int error; 1196 1197 error = 0; 1198 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1199 printf( 1200 "trying to add a filterop that is out of range: %d is beyond %d\n", 1201 ~filt, EVFILT_SYSCOUNT); 1202 return EINVAL; 1203 } 1204 mtx_lock(&filterops_lock); 1205 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1206 sysfilt_ops[~filt].for_fop != NULL) 1207 error = EEXIST; 1208 else { 1209 sysfilt_ops[~filt].for_fop = filtops; 1210 sysfilt_ops[~filt].for_refcnt = 0; 1211 } 1212 mtx_unlock(&filterops_lock); 1213 1214 return (error); 1215 } 1216 1217 int 1218 kqueue_del_filteropts(int filt) 1219 { 1220 int error; 1221 1222 error = 0; 1223 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1224 return EINVAL; 1225 1226 mtx_lock(&filterops_lock); 1227 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1228 sysfilt_ops[~filt].for_fop == NULL) 1229 error = EINVAL; 1230 else if (sysfilt_ops[~filt].for_refcnt != 0) 1231 error = EBUSY; 1232 else { 1233 sysfilt_ops[~filt].for_fop = &null_filtops; 1234 sysfilt_ops[~filt].for_refcnt = 0; 1235 } 1236 mtx_unlock(&filterops_lock); 1237 1238 return error; 1239 } 1240 1241 static struct filterops * 1242 kqueue_fo_find(int filt) 1243 { 1244 1245 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1246 return NULL; 1247 1248 if (sysfilt_ops[~filt].for_nolock) 1249 return sysfilt_ops[~filt].for_fop; 1250 1251 mtx_lock(&filterops_lock); 1252 sysfilt_ops[~filt].for_refcnt++; 1253 if (sysfilt_ops[~filt].for_fop == NULL) 1254 sysfilt_ops[~filt].for_fop = &null_filtops; 1255 mtx_unlock(&filterops_lock); 1256 1257 return sysfilt_ops[~filt].for_fop; 1258 } 1259 1260 static void 1261 kqueue_fo_release(int filt) 1262 { 1263 1264 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1265 return; 1266 1267 if (sysfilt_ops[~filt].for_nolock) 1268 return; 1269 1270 mtx_lock(&filterops_lock); 1271 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1272 ("filter object refcount not valid on release")); 1273 sysfilt_ops[~filt].for_refcnt--; 1274 mtx_unlock(&filterops_lock); 1275 } 1276 1277 /* 1278 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1279 * influence if memory allocation should wait. Make sure it is 0 if you 1280 * hold any mutexes. 1281 */ 1282 static int 1283 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1284 { 1285 struct filterops *fops; 1286 struct file *fp; 1287 struct knote *kn, *tkn; 1288 struct knlist *knl; 1289 int error, filt, event; 1290 int haskqglobal, filedesc_unlock; 1291 1292 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1293 return (EINVAL); 1294 1295 fp = NULL; 1296 kn = NULL; 1297 knl = NULL; 1298 error = 0; 1299 haskqglobal = 0; 1300 filedesc_unlock = 0; 1301 1302 filt = kev->filter; 1303 fops = kqueue_fo_find(filt); 1304 if (fops == NULL) 1305 return EINVAL; 1306 1307 if (kev->flags & EV_ADD) { 1308 /* 1309 * Prevent waiting with locks. Non-sleepable 1310 * allocation failures are handled in the loop, only 1311 * if the spare knote appears to be actually required. 1312 */ 1313 tkn = knote_alloc(waitok); 1314 } else { 1315 tkn = NULL; 1316 } 1317 1318 findkn: 1319 if (fops->f_isfd) { 1320 KASSERT(td != NULL, ("td is NULL")); 1321 if (kev->ident > INT_MAX) 1322 error = EBADF; 1323 else 1324 error = fget(td, kev->ident, &cap_event_rights, &fp); 1325 if (error) 1326 goto done; 1327 1328 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1329 kev->ident, 0) != 0) { 1330 /* try again */ 1331 fdrop(fp, td); 1332 fp = NULL; 1333 error = kqueue_expand(kq, fops, kev->ident, waitok); 1334 if (error) 1335 goto done; 1336 goto findkn; 1337 } 1338 1339 if (fp->f_type == DTYPE_KQUEUE) { 1340 /* 1341 * If we add some intelligence about what we are doing, 1342 * we should be able to support events on ourselves. 1343 * We need to know when we are doing this to prevent 1344 * getting both the knlist lock and the kq lock since 1345 * they are the same thing. 1346 */ 1347 if (fp->f_data == kq) { 1348 error = EINVAL; 1349 goto done; 1350 } 1351 1352 /* 1353 * Pre-lock the filedesc before the global 1354 * lock mutex, see the comment in 1355 * kqueue_close(). 1356 */ 1357 FILEDESC_XLOCK(td->td_proc->p_fd); 1358 filedesc_unlock = 1; 1359 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1360 } 1361 1362 KQ_LOCK(kq); 1363 if (kev->ident < kq->kq_knlistsize) { 1364 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1365 if (kev->filter == kn->kn_filter) 1366 break; 1367 } 1368 } else { 1369 if ((kev->flags & EV_ADD) == EV_ADD) 1370 kqueue_expand(kq, fops, kev->ident, waitok); 1371 1372 KQ_LOCK(kq); 1373 1374 /* 1375 * If possible, find an existing knote to use for this kevent. 1376 */ 1377 if (kev->filter == EVFILT_PROC && 1378 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1379 /* This is an internal creation of a process tracking 1380 * note. Don't attempt to coalesce this with an 1381 * existing note. 1382 */ 1383 ; 1384 } else if (kq->kq_knhashmask != 0) { 1385 struct klist *list; 1386 1387 list = &kq->kq_knhash[ 1388 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1389 SLIST_FOREACH(kn, list, kn_link) 1390 if (kev->ident == kn->kn_id && 1391 kev->filter == kn->kn_filter) 1392 break; 1393 } 1394 } 1395 1396 /* knote is in the process of changing, wait for it to stabilize. */ 1397 if (kn != NULL && kn_in_flux(kn)) { 1398 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1399 if (filedesc_unlock) { 1400 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1401 filedesc_unlock = 0; 1402 } 1403 kq->kq_state |= KQ_FLUXWAIT; 1404 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1405 if (fp != NULL) { 1406 fdrop(fp, td); 1407 fp = NULL; 1408 } 1409 goto findkn; 1410 } 1411 1412 /* 1413 * kn now contains the matching knote, or NULL if no match 1414 */ 1415 if (kn == NULL) { 1416 if (kev->flags & EV_ADD) { 1417 kn = tkn; 1418 tkn = NULL; 1419 if (kn == NULL) { 1420 KQ_UNLOCK(kq); 1421 error = ENOMEM; 1422 goto done; 1423 } 1424 kn->kn_fp = fp; 1425 kn->kn_kq = kq; 1426 kn->kn_fop = fops; 1427 /* 1428 * apply reference counts to knote structure, and 1429 * do not release it at the end of this routine. 1430 */ 1431 fops = NULL; 1432 fp = NULL; 1433 1434 kn->kn_sfflags = kev->fflags; 1435 kn->kn_sdata = kev->data; 1436 kev->fflags = 0; 1437 kev->data = 0; 1438 kn->kn_kevent = *kev; 1439 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1440 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1441 kn->kn_status = KN_DETACHED; 1442 kn_enter_flux(kn); 1443 1444 error = knote_attach(kn, kq); 1445 KQ_UNLOCK(kq); 1446 if (error != 0) { 1447 tkn = kn; 1448 goto done; 1449 } 1450 1451 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1452 knote_drop_detached(kn, td); 1453 goto done; 1454 } 1455 knl = kn_list_lock(kn); 1456 goto done_ev_add; 1457 } else { 1458 /* No matching knote and the EV_ADD flag is not set. */ 1459 KQ_UNLOCK(kq); 1460 error = ENOENT; 1461 goto done; 1462 } 1463 } 1464 1465 if (kev->flags & EV_DELETE) { 1466 kn_enter_flux(kn); 1467 KQ_UNLOCK(kq); 1468 knote_drop(kn, td); 1469 goto done; 1470 } 1471 1472 if (kev->flags & EV_FORCEONESHOT) { 1473 kn->kn_flags |= EV_ONESHOT; 1474 KNOTE_ACTIVATE(kn, 1); 1475 } 1476 1477 /* 1478 * The user may change some filter values after the initial EV_ADD, 1479 * but doing so will not reset any filter which has already been 1480 * triggered. 1481 */ 1482 kn->kn_status |= KN_SCAN; 1483 kn_enter_flux(kn); 1484 KQ_UNLOCK(kq); 1485 knl = kn_list_lock(kn); 1486 kn->kn_kevent.udata = kev->udata; 1487 if (!fops->f_isfd && fops->f_touch != NULL) { 1488 fops->f_touch(kn, kev, EVENT_REGISTER); 1489 } else { 1490 kn->kn_sfflags = kev->fflags; 1491 kn->kn_sdata = kev->data; 1492 } 1493 1494 /* 1495 * We can get here with kn->kn_knlist == NULL. This can happen when 1496 * the initial attach event decides that the event is "completed" 1497 * already. i.e. filt_procattach is called on a zombie process. It 1498 * will call filt_proc which will remove it from the list, and NULL 1499 * kn_knlist. 1500 */ 1501 done_ev_add: 1502 if ((kev->flags & EV_ENABLE) != 0) 1503 kn->kn_status &= ~KN_DISABLED; 1504 else if ((kev->flags & EV_DISABLE) != 0) 1505 kn->kn_status |= KN_DISABLED; 1506 1507 if ((kn->kn_status & KN_DISABLED) == 0) 1508 event = kn->kn_fop->f_event(kn, 0); 1509 else 1510 event = 0; 1511 1512 KQ_LOCK(kq); 1513 if (event) 1514 kn->kn_status |= KN_ACTIVE; 1515 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1516 KN_ACTIVE) 1517 knote_enqueue(kn); 1518 kn->kn_status &= ~KN_SCAN; 1519 kn_leave_flux(kn); 1520 kn_list_unlock(knl); 1521 KQ_UNLOCK_FLUX(kq); 1522 1523 done: 1524 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1525 if (filedesc_unlock) 1526 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1527 if (fp != NULL) 1528 fdrop(fp, td); 1529 knote_free(tkn); 1530 if (fops != NULL) 1531 kqueue_fo_release(filt); 1532 return (error); 1533 } 1534 1535 static int 1536 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1537 { 1538 int error; 1539 struct kqueue *kq; 1540 1541 error = 0; 1542 1543 kq = fp->f_data; 1544 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1545 return (EBADF); 1546 *kqp = kq; 1547 KQ_LOCK(kq); 1548 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1549 KQ_UNLOCK(kq); 1550 return (EBADF); 1551 } 1552 kq->kq_refcnt++; 1553 KQ_UNLOCK(kq); 1554 1555 return error; 1556 } 1557 1558 static void 1559 kqueue_release(struct kqueue *kq, int locked) 1560 { 1561 if (locked) 1562 KQ_OWNED(kq); 1563 else 1564 KQ_LOCK(kq); 1565 kq->kq_refcnt--; 1566 if (kq->kq_refcnt == 1) 1567 wakeup(&kq->kq_refcnt); 1568 if (!locked) 1569 KQ_UNLOCK(kq); 1570 } 1571 1572 static void 1573 kqueue_schedtask(struct kqueue *kq) 1574 { 1575 1576 KQ_OWNED(kq); 1577 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1578 ("scheduling kqueue task while draining")); 1579 1580 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1581 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1582 kq->kq_state |= KQ_TASKSCHED; 1583 } 1584 } 1585 1586 /* 1587 * Expand the kq to make sure we have storage for fops/ident pair. 1588 * 1589 * Return 0 on success (or no work necessary), return errno on failure. 1590 * 1591 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1592 * If kqueue_register is called from a non-fd context, there usually/should 1593 * be no locks held. 1594 */ 1595 static int 1596 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1597 int waitok) 1598 { 1599 struct klist *list, *tmp_knhash, *to_free; 1600 u_long tmp_knhashmask; 1601 int size; 1602 int fd; 1603 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1604 1605 KQ_NOTOWNED(kq); 1606 1607 to_free = NULL; 1608 if (fops->f_isfd) { 1609 fd = ident; 1610 if (kq->kq_knlistsize <= fd) { 1611 size = kq->kq_knlistsize; 1612 while (size <= fd) 1613 size += KQEXTENT; 1614 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1615 if (list == NULL) 1616 return ENOMEM; 1617 KQ_LOCK(kq); 1618 if (kq->kq_knlistsize > fd) { 1619 to_free = list; 1620 list = NULL; 1621 } else { 1622 if (kq->kq_knlist != NULL) { 1623 bcopy(kq->kq_knlist, list, 1624 kq->kq_knlistsize * sizeof(*list)); 1625 to_free = kq->kq_knlist; 1626 kq->kq_knlist = NULL; 1627 } 1628 bzero((caddr_t)list + 1629 kq->kq_knlistsize * sizeof(*list), 1630 (size - kq->kq_knlistsize) * sizeof(*list)); 1631 kq->kq_knlistsize = size; 1632 kq->kq_knlist = list; 1633 } 1634 KQ_UNLOCK(kq); 1635 } 1636 } else { 1637 if (kq->kq_knhashmask == 0) { 1638 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1639 &tmp_knhashmask); 1640 if (tmp_knhash == NULL) 1641 return ENOMEM; 1642 KQ_LOCK(kq); 1643 if (kq->kq_knhashmask == 0) { 1644 kq->kq_knhash = tmp_knhash; 1645 kq->kq_knhashmask = tmp_knhashmask; 1646 } else { 1647 to_free = tmp_knhash; 1648 } 1649 KQ_UNLOCK(kq); 1650 } 1651 } 1652 free(to_free, M_KQUEUE); 1653 1654 KQ_NOTOWNED(kq); 1655 return 0; 1656 } 1657 1658 static void 1659 kqueue_task(void *arg, int pending) 1660 { 1661 struct kqueue *kq; 1662 int haskqglobal; 1663 1664 haskqglobal = 0; 1665 kq = arg; 1666 1667 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1668 KQ_LOCK(kq); 1669 1670 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1671 1672 kq->kq_state &= ~KQ_TASKSCHED; 1673 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1674 wakeup(&kq->kq_state); 1675 } 1676 KQ_UNLOCK(kq); 1677 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1678 } 1679 1680 /* 1681 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1682 * We treat KN_MARKER knotes as if they are in flux. 1683 */ 1684 static int 1685 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1686 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1687 { 1688 struct kevent *kevp; 1689 struct knote *kn, *marker; 1690 struct knlist *knl; 1691 sbintime_t asbt, rsbt; 1692 int count, error, haskqglobal, influx, nkev, touch; 1693 1694 count = maxevents; 1695 nkev = 0; 1696 error = 0; 1697 haskqglobal = 0; 1698 1699 if (maxevents == 0) 1700 goto done_nl; 1701 1702 rsbt = 0; 1703 if (tsp != NULL) { 1704 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1705 tsp->tv_nsec >= 1000000000) { 1706 error = EINVAL; 1707 goto done_nl; 1708 } 1709 if (timespecisset(tsp)) { 1710 if (tsp->tv_sec <= INT32_MAX) { 1711 rsbt = tstosbt(*tsp); 1712 if (TIMESEL(&asbt, rsbt)) 1713 asbt += tc_tick_sbt; 1714 if (asbt <= SBT_MAX - rsbt) 1715 asbt += rsbt; 1716 else 1717 asbt = 0; 1718 rsbt >>= tc_precexp; 1719 } else 1720 asbt = 0; 1721 } else 1722 asbt = -1; 1723 } else 1724 asbt = 0; 1725 marker = knote_alloc(1); 1726 marker->kn_status = KN_MARKER; 1727 KQ_LOCK(kq); 1728 1729 retry: 1730 kevp = keva; 1731 if (kq->kq_count == 0) { 1732 if (asbt == -1) { 1733 error = EWOULDBLOCK; 1734 } else { 1735 kq->kq_state |= KQ_SLEEP; 1736 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1737 "kqread", asbt, rsbt, C_ABSOLUTE); 1738 } 1739 if (error == 0) 1740 goto retry; 1741 /* don't restart after signals... */ 1742 if (error == ERESTART) 1743 error = EINTR; 1744 else if (error == EWOULDBLOCK) 1745 error = 0; 1746 goto done; 1747 } 1748 1749 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1750 influx = 0; 1751 while (count) { 1752 KQ_OWNED(kq); 1753 kn = TAILQ_FIRST(&kq->kq_head); 1754 1755 if ((kn->kn_status == KN_MARKER && kn != marker) || 1756 kn_in_flux(kn)) { 1757 if (influx) { 1758 influx = 0; 1759 KQ_FLUX_WAKEUP(kq); 1760 } 1761 kq->kq_state |= KQ_FLUXWAIT; 1762 error = msleep(kq, &kq->kq_lock, PSOCK, 1763 "kqflxwt", 0); 1764 continue; 1765 } 1766 1767 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1768 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1769 kn->kn_status &= ~KN_QUEUED; 1770 kq->kq_count--; 1771 continue; 1772 } 1773 if (kn == marker) { 1774 KQ_FLUX_WAKEUP(kq); 1775 if (count == maxevents) 1776 goto retry; 1777 goto done; 1778 } 1779 KASSERT(!kn_in_flux(kn), 1780 ("knote %p is unexpectedly in flux", kn)); 1781 1782 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1783 kn->kn_status &= ~KN_QUEUED; 1784 kn_enter_flux(kn); 1785 kq->kq_count--; 1786 KQ_UNLOCK(kq); 1787 /* 1788 * We don't need to lock the list since we've 1789 * marked it as in flux. 1790 */ 1791 knote_drop(kn, td); 1792 KQ_LOCK(kq); 1793 continue; 1794 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1795 kn->kn_status &= ~KN_QUEUED; 1796 kn_enter_flux(kn); 1797 kq->kq_count--; 1798 KQ_UNLOCK(kq); 1799 /* 1800 * We don't need to lock the list since we've 1801 * marked the knote as being in flux. 1802 */ 1803 *kevp = kn->kn_kevent; 1804 knote_drop(kn, td); 1805 KQ_LOCK(kq); 1806 kn = NULL; 1807 } else { 1808 kn->kn_status |= KN_SCAN; 1809 kn_enter_flux(kn); 1810 KQ_UNLOCK(kq); 1811 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1812 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1813 knl = kn_list_lock(kn); 1814 if (kn->kn_fop->f_event(kn, 0) == 0) { 1815 KQ_LOCK(kq); 1816 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1817 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1818 KN_SCAN); 1819 kn_leave_flux(kn); 1820 kq->kq_count--; 1821 kn_list_unlock(knl); 1822 influx = 1; 1823 continue; 1824 } 1825 touch = (!kn->kn_fop->f_isfd && 1826 kn->kn_fop->f_touch != NULL); 1827 if (touch) 1828 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1829 else 1830 *kevp = kn->kn_kevent; 1831 KQ_LOCK(kq); 1832 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1833 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1834 /* 1835 * Manually clear knotes who weren't 1836 * 'touch'ed. 1837 */ 1838 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1839 kn->kn_data = 0; 1840 kn->kn_fflags = 0; 1841 } 1842 if (kn->kn_flags & EV_DISPATCH) 1843 kn->kn_status |= KN_DISABLED; 1844 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1845 kq->kq_count--; 1846 } else 1847 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1848 1849 kn->kn_status &= ~KN_SCAN; 1850 kn_leave_flux(kn); 1851 kn_list_unlock(knl); 1852 influx = 1; 1853 } 1854 1855 /* we are returning a copy to the user */ 1856 kevp++; 1857 nkev++; 1858 count--; 1859 1860 if (nkev == KQ_NEVENTS) { 1861 influx = 0; 1862 KQ_UNLOCK_FLUX(kq); 1863 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1864 nkev = 0; 1865 kevp = keva; 1866 KQ_LOCK(kq); 1867 if (error) 1868 break; 1869 } 1870 } 1871 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1872 done: 1873 KQ_OWNED(kq); 1874 KQ_UNLOCK_FLUX(kq); 1875 knote_free(marker); 1876 done_nl: 1877 KQ_NOTOWNED(kq); 1878 if (nkev != 0) 1879 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1880 td->td_retval[0] = maxevents - count; 1881 return (error); 1882 } 1883 1884 /*ARGSUSED*/ 1885 static int 1886 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1887 struct ucred *active_cred, struct thread *td) 1888 { 1889 /* 1890 * Enabling sigio causes two major problems: 1891 * 1) infinite recursion: 1892 * Synopsys: kevent is being used to track signals and have FIOASYNC 1893 * set. On receipt of a signal this will cause a kqueue to recurse 1894 * into itself over and over. Sending the sigio causes the kqueue 1895 * to become ready, which in turn posts sigio again, forever. 1896 * Solution: this can be solved by setting a flag in the kqueue that 1897 * we have a SIGIO in progress. 1898 * 2) locking problems: 1899 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1900 * us above the proc and pgrp locks. 1901 * Solution: Post a signal using an async mechanism, being sure to 1902 * record a generation count in the delivery so that we do not deliver 1903 * a signal to the wrong process. 1904 * 1905 * Note, these two mechanisms are somewhat mutually exclusive! 1906 */ 1907 #if 0 1908 struct kqueue *kq; 1909 1910 kq = fp->f_data; 1911 switch (cmd) { 1912 case FIOASYNC: 1913 if (*(int *)data) { 1914 kq->kq_state |= KQ_ASYNC; 1915 } else { 1916 kq->kq_state &= ~KQ_ASYNC; 1917 } 1918 return (0); 1919 1920 case FIOSETOWN: 1921 return (fsetown(*(int *)data, &kq->kq_sigio)); 1922 1923 case FIOGETOWN: 1924 *(int *)data = fgetown(&kq->kq_sigio); 1925 return (0); 1926 } 1927 #endif 1928 1929 return (ENOTTY); 1930 } 1931 1932 /*ARGSUSED*/ 1933 static int 1934 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1935 struct thread *td) 1936 { 1937 struct kqueue *kq; 1938 int revents = 0; 1939 int error; 1940 1941 if ((error = kqueue_acquire(fp, &kq))) 1942 return POLLERR; 1943 1944 KQ_LOCK(kq); 1945 if (events & (POLLIN | POLLRDNORM)) { 1946 if (kq->kq_count) { 1947 revents |= events & (POLLIN | POLLRDNORM); 1948 } else { 1949 selrecord(td, &kq->kq_sel); 1950 if (SEL_WAITING(&kq->kq_sel)) 1951 kq->kq_state |= KQ_SEL; 1952 } 1953 } 1954 kqueue_release(kq, 1); 1955 KQ_UNLOCK(kq); 1956 return (revents); 1957 } 1958 1959 /*ARGSUSED*/ 1960 static int 1961 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1962 struct thread *td) 1963 { 1964 1965 bzero((void *)st, sizeof *st); 1966 /* 1967 * We no longer return kq_count because the unlocked value is useless. 1968 * If you spent all this time getting the count, why not spend your 1969 * syscall better by calling kevent? 1970 * 1971 * XXX - This is needed for libc_r. 1972 */ 1973 st->st_mode = S_IFIFO; 1974 return (0); 1975 } 1976 1977 static void 1978 kqueue_drain(struct kqueue *kq, struct thread *td) 1979 { 1980 struct knote *kn; 1981 int i; 1982 1983 KQ_LOCK(kq); 1984 1985 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1986 ("kqueue already closing")); 1987 kq->kq_state |= KQ_CLOSING; 1988 if (kq->kq_refcnt > 1) 1989 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1990 1991 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1992 1993 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1994 ("kqueue's knlist not empty")); 1995 1996 for (i = 0; i < kq->kq_knlistsize; i++) { 1997 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1998 if (kn_in_flux(kn)) { 1999 kq->kq_state |= KQ_FLUXWAIT; 2000 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 2001 continue; 2002 } 2003 kn_enter_flux(kn); 2004 KQ_UNLOCK(kq); 2005 knote_drop(kn, td); 2006 KQ_LOCK(kq); 2007 } 2008 } 2009 if (kq->kq_knhashmask != 0) { 2010 for (i = 0; i <= kq->kq_knhashmask; i++) { 2011 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 2012 if (kn_in_flux(kn)) { 2013 kq->kq_state |= KQ_FLUXWAIT; 2014 msleep(kq, &kq->kq_lock, PSOCK, 2015 "kqclo2", 0); 2016 continue; 2017 } 2018 kn_enter_flux(kn); 2019 KQ_UNLOCK(kq); 2020 knote_drop(kn, td); 2021 KQ_LOCK(kq); 2022 } 2023 } 2024 } 2025 2026 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 2027 kq->kq_state |= KQ_TASKDRAIN; 2028 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 2029 } 2030 2031 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2032 selwakeuppri(&kq->kq_sel, PSOCK); 2033 if (!SEL_WAITING(&kq->kq_sel)) 2034 kq->kq_state &= ~KQ_SEL; 2035 } 2036 2037 KQ_UNLOCK(kq); 2038 } 2039 2040 static void 2041 kqueue_destroy(struct kqueue *kq) 2042 { 2043 2044 KASSERT(kq->kq_fdp == NULL, 2045 ("kqueue still attached to a file descriptor")); 2046 seldrain(&kq->kq_sel); 2047 knlist_destroy(&kq->kq_sel.si_note); 2048 mtx_destroy(&kq->kq_lock); 2049 2050 if (kq->kq_knhash != NULL) 2051 free(kq->kq_knhash, M_KQUEUE); 2052 if (kq->kq_knlist != NULL) 2053 free(kq->kq_knlist, M_KQUEUE); 2054 2055 funsetown(&kq->kq_sigio); 2056 } 2057 2058 /*ARGSUSED*/ 2059 static int 2060 kqueue_close(struct file *fp, struct thread *td) 2061 { 2062 struct kqueue *kq = fp->f_data; 2063 struct filedesc *fdp; 2064 int error; 2065 int filedesc_unlock; 2066 2067 if ((error = kqueue_acquire(fp, &kq))) 2068 return error; 2069 kqueue_drain(kq, td); 2070 2071 /* 2072 * We could be called due to the knote_drop() doing fdrop(), 2073 * called from kqueue_register(). In this case the global 2074 * lock is owned, and filedesc sx is locked before, to not 2075 * take the sleepable lock after non-sleepable. 2076 */ 2077 fdp = kq->kq_fdp; 2078 kq->kq_fdp = NULL; 2079 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 2080 FILEDESC_XLOCK(fdp); 2081 filedesc_unlock = 1; 2082 } else 2083 filedesc_unlock = 0; 2084 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 2085 if (filedesc_unlock) 2086 FILEDESC_XUNLOCK(fdp); 2087 2088 kqueue_destroy(kq); 2089 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 2090 crfree(kq->kq_cred); 2091 free(kq, M_KQUEUE); 2092 fp->f_data = NULL; 2093 2094 return (0); 2095 } 2096 2097 static int 2098 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 2099 { 2100 2101 kif->kf_type = KF_TYPE_KQUEUE; 2102 return (0); 2103 } 2104 2105 static void 2106 kqueue_wakeup(struct kqueue *kq) 2107 { 2108 KQ_OWNED(kq); 2109 2110 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2111 kq->kq_state &= ~KQ_SLEEP; 2112 wakeup(kq); 2113 } 2114 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2115 selwakeuppri(&kq->kq_sel, PSOCK); 2116 if (!SEL_WAITING(&kq->kq_sel)) 2117 kq->kq_state &= ~KQ_SEL; 2118 } 2119 if (!knlist_empty(&kq->kq_sel.si_note)) 2120 kqueue_schedtask(kq); 2121 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2122 pgsigio(&kq->kq_sigio, SIGIO, 0); 2123 } 2124 } 2125 2126 /* 2127 * Walk down a list of knotes, activating them if their event has triggered. 2128 * 2129 * There is a possibility to optimize in the case of one kq watching another. 2130 * Instead of scheduling a task to wake it up, you could pass enough state 2131 * down the chain to make up the parent kqueue. Make this code functional 2132 * first. 2133 */ 2134 void 2135 knote(struct knlist *list, long hint, int lockflags) 2136 { 2137 struct kqueue *kq; 2138 struct knote *kn, *tkn; 2139 int error; 2140 2141 if (list == NULL) 2142 return; 2143 2144 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2145 2146 if ((lockflags & KNF_LISTLOCKED) == 0) 2147 list->kl_lock(list->kl_lockarg); 2148 2149 /* 2150 * If we unlock the list lock (and enter influx), we can 2151 * eliminate the kqueue scheduling, but this will introduce 2152 * four lock/unlock's for each knote to test. Also, marker 2153 * would be needed to keep iteration position, since filters 2154 * or other threads could remove events. 2155 */ 2156 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2157 kq = kn->kn_kq; 2158 KQ_LOCK(kq); 2159 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2160 /* 2161 * Do not process the influx notes, except for 2162 * the influx coming from the kq unlock in the 2163 * kqueue_scan(). In the later case, we do 2164 * not interfere with the scan, since the code 2165 * fragment in kqueue_scan() locks the knlist, 2166 * and cannot proceed until we finished. 2167 */ 2168 KQ_UNLOCK(kq); 2169 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2170 kn_enter_flux(kn); 2171 KQ_UNLOCK(kq); 2172 error = kn->kn_fop->f_event(kn, hint); 2173 KQ_LOCK(kq); 2174 kn_leave_flux(kn); 2175 if (error) 2176 KNOTE_ACTIVATE(kn, 1); 2177 KQ_UNLOCK_FLUX(kq); 2178 } else { 2179 kn->kn_status |= KN_HASKQLOCK; 2180 if (kn->kn_fop->f_event(kn, hint)) 2181 KNOTE_ACTIVATE(kn, 1); 2182 kn->kn_status &= ~KN_HASKQLOCK; 2183 KQ_UNLOCK(kq); 2184 } 2185 } 2186 if ((lockflags & KNF_LISTLOCKED) == 0) 2187 list->kl_unlock(list->kl_lockarg); 2188 } 2189 2190 /* 2191 * add a knote to a knlist 2192 */ 2193 void 2194 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2195 { 2196 2197 KNL_ASSERT_LOCK(knl, islocked); 2198 KQ_NOTOWNED(kn->kn_kq); 2199 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2200 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2201 ("knote %p was not detached", kn)); 2202 if (!islocked) 2203 knl->kl_lock(knl->kl_lockarg); 2204 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2205 if (!islocked) 2206 knl->kl_unlock(knl->kl_lockarg); 2207 KQ_LOCK(kn->kn_kq); 2208 kn->kn_knlist = knl; 2209 kn->kn_status &= ~KN_DETACHED; 2210 KQ_UNLOCK(kn->kn_kq); 2211 } 2212 2213 static void 2214 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2215 int kqislocked) 2216 { 2217 2218 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2219 KNL_ASSERT_LOCK(knl, knlislocked); 2220 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2221 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2222 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2223 ("knote %p was already detached", kn)); 2224 if (!knlislocked) 2225 knl->kl_lock(knl->kl_lockarg); 2226 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2227 kn->kn_knlist = NULL; 2228 if (!knlislocked) 2229 kn_list_unlock(knl); 2230 if (!kqislocked) 2231 KQ_LOCK(kn->kn_kq); 2232 kn->kn_status |= KN_DETACHED; 2233 if (!kqislocked) 2234 KQ_UNLOCK(kn->kn_kq); 2235 } 2236 2237 /* 2238 * remove knote from the specified knlist 2239 */ 2240 void 2241 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2242 { 2243 2244 knlist_remove_kq(knl, kn, islocked, 0); 2245 } 2246 2247 int 2248 knlist_empty(struct knlist *knl) 2249 { 2250 2251 KNL_ASSERT_LOCKED(knl); 2252 return (SLIST_EMPTY(&knl->kl_list)); 2253 } 2254 2255 static struct mtx knlist_lock; 2256 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2257 MTX_DEF); 2258 static void knlist_mtx_lock(void *arg); 2259 static void knlist_mtx_unlock(void *arg); 2260 2261 static void 2262 knlist_mtx_lock(void *arg) 2263 { 2264 2265 mtx_lock((struct mtx *)arg); 2266 } 2267 2268 static void 2269 knlist_mtx_unlock(void *arg) 2270 { 2271 2272 mtx_unlock((struct mtx *)arg); 2273 } 2274 2275 static void 2276 knlist_mtx_assert_locked(void *arg) 2277 { 2278 2279 mtx_assert((struct mtx *)arg, MA_OWNED); 2280 } 2281 2282 static void 2283 knlist_mtx_assert_unlocked(void *arg) 2284 { 2285 2286 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2287 } 2288 2289 static void 2290 knlist_rw_rlock(void *arg) 2291 { 2292 2293 rw_rlock((struct rwlock *)arg); 2294 } 2295 2296 static void 2297 knlist_rw_runlock(void *arg) 2298 { 2299 2300 rw_runlock((struct rwlock *)arg); 2301 } 2302 2303 static void 2304 knlist_rw_assert_locked(void *arg) 2305 { 2306 2307 rw_assert((struct rwlock *)arg, RA_LOCKED); 2308 } 2309 2310 static void 2311 knlist_rw_assert_unlocked(void *arg) 2312 { 2313 2314 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2315 } 2316 2317 void 2318 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2319 void (*kl_unlock)(void *), 2320 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2321 { 2322 2323 if (lock == NULL) 2324 knl->kl_lockarg = &knlist_lock; 2325 else 2326 knl->kl_lockarg = lock; 2327 2328 if (kl_lock == NULL) 2329 knl->kl_lock = knlist_mtx_lock; 2330 else 2331 knl->kl_lock = kl_lock; 2332 if (kl_unlock == NULL) 2333 knl->kl_unlock = knlist_mtx_unlock; 2334 else 2335 knl->kl_unlock = kl_unlock; 2336 if (kl_assert_locked == NULL) 2337 knl->kl_assert_locked = knlist_mtx_assert_locked; 2338 else 2339 knl->kl_assert_locked = kl_assert_locked; 2340 if (kl_assert_unlocked == NULL) 2341 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2342 else 2343 knl->kl_assert_unlocked = kl_assert_unlocked; 2344 2345 knl->kl_autodestroy = 0; 2346 SLIST_INIT(&knl->kl_list); 2347 } 2348 2349 void 2350 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2351 { 2352 2353 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2354 } 2355 2356 struct knlist * 2357 knlist_alloc(struct mtx *lock) 2358 { 2359 struct knlist *knl; 2360 2361 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2362 knlist_init_mtx(knl, lock); 2363 return (knl); 2364 } 2365 2366 void 2367 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2368 { 2369 2370 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2371 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2372 } 2373 2374 void 2375 knlist_destroy(struct knlist *knl) 2376 { 2377 2378 KASSERT(KNLIST_EMPTY(knl), 2379 ("destroying knlist %p with knotes on it", knl)); 2380 } 2381 2382 void 2383 knlist_detach(struct knlist *knl) 2384 { 2385 2386 KNL_ASSERT_LOCKED(knl); 2387 knl->kl_autodestroy = 1; 2388 if (knlist_empty(knl)) { 2389 knlist_destroy(knl); 2390 free(knl, M_KQUEUE); 2391 } 2392 } 2393 2394 /* 2395 * Even if we are locked, we may need to drop the lock to allow any influx 2396 * knotes time to "settle". 2397 */ 2398 void 2399 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2400 { 2401 struct knote *kn, *kn2; 2402 struct kqueue *kq; 2403 2404 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2405 if (islocked) 2406 KNL_ASSERT_LOCKED(knl); 2407 else { 2408 KNL_ASSERT_UNLOCKED(knl); 2409 again: /* need to reacquire lock since we have dropped it */ 2410 knl->kl_lock(knl->kl_lockarg); 2411 } 2412 2413 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2414 kq = kn->kn_kq; 2415 KQ_LOCK(kq); 2416 if (kn_in_flux(kn)) { 2417 KQ_UNLOCK(kq); 2418 continue; 2419 } 2420 knlist_remove_kq(knl, kn, 1, 1); 2421 if (killkn) { 2422 kn_enter_flux(kn); 2423 KQ_UNLOCK(kq); 2424 knote_drop_detached(kn, td); 2425 } else { 2426 /* Make sure cleared knotes disappear soon */ 2427 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2428 KQ_UNLOCK(kq); 2429 } 2430 kq = NULL; 2431 } 2432 2433 if (!SLIST_EMPTY(&knl->kl_list)) { 2434 /* there are still in flux knotes remaining */ 2435 kn = SLIST_FIRST(&knl->kl_list); 2436 kq = kn->kn_kq; 2437 KQ_LOCK(kq); 2438 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2439 knl->kl_unlock(knl->kl_lockarg); 2440 kq->kq_state |= KQ_FLUXWAIT; 2441 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2442 kq = NULL; 2443 goto again; 2444 } 2445 2446 if (islocked) 2447 KNL_ASSERT_LOCKED(knl); 2448 else { 2449 knl->kl_unlock(knl->kl_lockarg); 2450 KNL_ASSERT_UNLOCKED(knl); 2451 } 2452 } 2453 2454 /* 2455 * Remove all knotes referencing a specified fd must be called with FILEDESC 2456 * lock. This prevents a race where a new fd comes along and occupies the 2457 * entry and we attach a knote to the fd. 2458 */ 2459 void 2460 knote_fdclose(struct thread *td, int fd) 2461 { 2462 struct filedesc *fdp = td->td_proc->p_fd; 2463 struct kqueue *kq; 2464 struct knote *kn; 2465 int influx; 2466 2467 FILEDESC_XLOCK_ASSERT(fdp); 2468 2469 /* 2470 * We shouldn't have to worry about new kevents appearing on fd 2471 * since filedesc is locked. 2472 */ 2473 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2474 KQ_LOCK(kq); 2475 2476 again: 2477 influx = 0; 2478 while (kq->kq_knlistsize > fd && 2479 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2480 if (kn_in_flux(kn)) { 2481 /* someone else might be waiting on our knote */ 2482 if (influx) 2483 wakeup(kq); 2484 kq->kq_state |= KQ_FLUXWAIT; 2485 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2486 goto again; 2487 } 2488 kn_enter_flux(kn); 2489 KQ_UNLOCK(kq); 2490 influx = 1; 2491 knote_drop(kn, td); 2492 KQ_LOCK(kq); 2493 } 2494 KQ_UNLOCK_FLUX(kq); 2495 } 2496 } 2497 2498 static int 2499 knote_attach(struct knote *kn, struct kqueue *kq) 2500 { 2501 struct klist *list; 2502 2503 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2504 KQ_OWNED(kq); 2505 2506 if (kn->kn_fop->f_isfd) { 2507 if (kn->kn_id >= kq->kq_knlistsize) 2508 return (ENOMEM); 2509 list = &kq->kq_knlist[kn->kn_id]; 2510 } else { 2511 if (kq->kq_knhash == NULL) 2512 return (ENOMEM); 2513 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2514 } 2515 SLIST_INSERT_HEAD(list, kn, kn_link); 2516 return (0); 2517 } 2518 2519 static void 2520 knote_drop(struct knote *kn, struct thread *td) 2521 { 2522 2523 if ((kn->kn_status & KN_DETACHED) == 0) 2524 kn->kn_fop->f_detach(kn); 2525 knote_drop_detached(kn, td); 2526 } 2527 2528 static void 2529 knote_drop_detached(struct knote *kn, struct thread *td) 2530 { 2531 struct kqueue *kq; 2532 struct klist *list; 2533 2534 kq = kn->kn_kq; 2535 2536 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2537 ("knote %p still attached", kn)); 2538 KQ_NOTOWNED(kq); 2539 2540 KQ_LOCK(kq); 2541 KASSERT(kn->kn_influx == 1, 2542 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2543 2544 if (kn->kn_fop->f_isfd) 2545 list = &kq->kq_knlist[kn->kn_id]; 2546 else 2547 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2548 2549 if (!SLIST_EMPTY(list)) 2550 SLIST_REMOVE(list, kn, knote, kn_link); 2551 if (kn->kn_status & KN_QUEUED) 2552 knote_dequeue(kn); 2553 KQ_UNLOCK_FLUX(kq); 2554 2555 if (kn->kn_fop->f_isfd) { 2556 fdrop(kn->kn_fp, td); 2557 kn->kn_fp = NULL; 2558 } 2559 kqueue_fo_release(kn->kn_kevent.filter); 2560 kn->kn_fop = NULL; 2561 knote_free(kn); 2562 } 2563 2564 static void 2565 knote_enqueue(struct knote *kn) 2566 { 2567 struct kqueue *kq = kn->kn_kq; 2568 2569 KQ_OWNED(kn->kn_kq); 2570 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2571 2572 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2573 kn->kn_status |= KN_QUEUED; 2574 kq->kq_count++; 2575 kqueue_wakeup(kq); 2576 } 2577 2578 static void 2579 knote_dequeue(struct knote *kn) 2580 { 2581 struct kqueue *kq = kn->kn_kq; 2582 2583 KQ_OWNED(kn->kn_kq); 2584 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2585 2586 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2587 kn->kn_status &= ~KN_QUEUED; 2588 kq->kq_count--; 2589 } 2590 2591 static void 2592 knote_init(void) 2593 { 2594 2595 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2596 NULL, NULL, UMA_ALIGN_PTR, 0); 2597 } 2598 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2599 2600 static struct knote * 2601 knote_alloc(int waitok) 2602 { 2603 2604 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | 2605 M_ZERO)); 2606 } 2607 2608 static void 2609 knote_free(struct knote *kn) 2610 { 2611 2612 uma_zfree(knote_zone, kn); 2613 } 2614 2615 /* 2616 * Register the kev w/ the kq specified by fd. 2617 */ 2618 int 2619 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2620 { 2621 struct kqueue *kq; 2622 struct file *fp; 2623 cap_rights_t rights; 2624 int error; 2625 2626 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2627 if (error != 0) 2628 return (error); 2629 if ((error = kqueue_acquire(fp, &kq)) != 0) 2630 goto noacquire; 2631 2632 error = kqueue_register(kq, kev, td, waitok); 2633 kqueue_release(kq, 0); 2634 2635 noacquire: 2636 fdrop(fp, td); 2637 return (error); 2638 } 2639