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 #ifndef _SYS_SYSPROTO_H_ 891 struct kevent_args { 892 int fd; 893 const struct kevent *changelist; 894 int nchanges; 895 struct kevent *eventlist; 896 int nevents; 897 const struct timespec *timeout; 898 }; 899 #endif 900 int 901 sys_kevent(struct thread *td, struct kevent_args *uap) 902 { 903 struct timespec ts, *tsp; 904 struct kevent_copyops k_ops = { uap, 905 kevent_copyout, 906 kevent_copyin}; 907 int error; 908 #ifdef KTRACE 909 struct uio ktruio; 910 struct iovec ktriov; 911 struct uio *ktruioin = NULL; 912 struct uio *ktruioout = NULL; 913 #endif 914 915 if (uap->timeout != NULL) { 916 error = copyin(uap->timeout, &ts, sizeof(ts)); 917 if (error) 918 return (error); 919 tsp = &ts; 920 } else 921 tsp = NULL; 922 923 #ifdef KTRACE 924 if (KTRPOINT(td, KTR_GENIO)) { 925 ktriov.iov_base = uap->changelist; 926 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 927 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 928 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 929 .uio_td = td }; 930 ktruioin = cloneuio(&ktruio); 931 ktriov.iov_base = uap->eventlist; 932 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 933 ktruioout = cloneuio(&ktruio); 934 } 935 #endif 936 937 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 938 &k_ops, tsp); 939 940 #ifdef KTRACE 941 if (ktruioin != NULL) { 942 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 943 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 944 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 945 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 946 } 947 #endif 948 949 return (error); 950 } 951 952 /* 953 * Copy 'count' items into the destination list pointed to by uap->eventlist. 954 */ 955 static int 956 kevent_copyout(void *arg, struct kevent *kevp, int count) 957 { 958 struct kevent_args *uap; 959 int error; 960 961 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 962 uap = (struct kevent_args *)arg; 963 964 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 965 if (error == 0) 966 uap->eventlist += count; 967 return (error); 968 } 969 970 /* 971 * Copy 'count' items from the list pointed to by uap->changelist. 972 */ 973 static int 974 kevent_copyin(void *arg, struct kevent *kevp, int count) 975 { 976 struct kevent_args *uap; 977 int error; 978 979 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 980 uap = (struct kevent_args *)arg; 981 982 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 983 if (error == 0) 984 uap->changelist += count; 985 return (error); 986 } 987 988 int 989 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 990 struct kevent_copyops *k_ops, const struct timespec *timeout) 991 { 992 cap_rights_t rights; 993 struct file *fp; 994 int error; 995 996 cap_rights_init(&rights); 997 if (nchanges > 0) 998 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 999 if (nevents > 0) 1000 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 1001 error = fget(td, fd, &rights, &fp); 1002 if (error != 0) 1003 return (error); 1004 1005 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 1006 fdrop(fp, td); 1007 1008 return (error); 1009 } 1010 1011 static int 1012 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 1013 struct kevent_copyops *k_ops, const struct timespec *timeout) 1014 { 1015 struct kevent keva[KQ_NEVENTS]; 1016 struct kevent *kevp, *changes; 1017 int i, n, nerrors, error; 1018 1019 nerrors = 0; 1020 while (nchanges > 0) { 1021 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 1022 error = k_ops->k_copyin(k_ops->arg, keva, n); 1023 if (error) 1024 return (error); 1025 changes = keva; 1026 for (i = 0; i < n; i++) { 1027 kevp = &changes[i]; 1028 if (!kevp->filter) 1029 continue; 1030 kevp->flags &= ~EV_SYSFLAGS; 1031 error = kqueue_register(kq, kevp, td, 1); 1032 if (error || (kevp->flags & EV_RECEIPT)) { 1033 if (nevents == 0) 1034 return (error); 1035 kevp->flags = EV_ERROR; 1036 kevp->data = error; 1037 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 1038 nevents--; 1039 nerrors++; 1040 } 1041 } 1042 nchanges -= n; 1043 } 1044 if (nerrors) { 1045 td->td_retval[0] = nerrors; 1046 return (0); 1047 } 1048 1049 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1050 } 1051 1052 int 1053 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1054 struct kevent_copyops *k_ops, const struct timespec *timeout) 1055 { 1056 struct kqueue *kq; 1057 int error; 1058 1059 error = kqueue_acquire(fp, &kq); 1060 if (error != 0) 1061 return (error); 1062 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1063 kqueue_release(kq, 0); 1064 return (error); 1065 } 1066 1067 /* 1068 * Performs a kevent() call on a temporarily created kqueue. This can be 1069 * used to perform one-shot polling, similar to poll() and select(). 1070 */ 1071 int 1072 kern_kevent_anonymous(struct thread *td, int nevents, 1073 struct kevent_copyops *k_ops) 1074 { 1075 struct kqueue kq = {}; 1076 int error; 1077 1078 kqueue_init(&kq); 1079 kq.kq_refcnt = 1; 1080 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1081 kqueue_drain(&kq, td); 1082 kqueue_destroy(&kq); 1083 return (error); 1084 } 1085 1086 int 1087 kqueue_add_filteropts(int filt, struct filterops *filtops) 1088 { 1089 int error; 1090 1091 error = 0; 1092 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1093 printf( 1094 "trying to add a filterop that is out of range: %d is beyond %d\n", 1095 ~filt, EVFILT_SYSCOUNT); 1096 return EINVAL; 1097 } 1098 mtx_lock(&filterops_lock); 1099 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1100 sysfilt_ops[~filt].for_fop != NULL) 1101 error = EEXIST; 1102 else { 1103 sysfilt_ops[~filt].for_fop = filtops; 1104 sysfilt_ops[~filt].for_refcnt = 0; 1105 } 1106 mtx_unlock(&filterops_lock); 1107 1108 return (error); 1109 } 1110 1111 int 1112 kqueue_del_filteropts(int filt) 1113 { 1114 int error; 1115 1116 error = 0; 1117 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1118 return EINVAL; 1119 1120 mtx_lock(&filterops_lock); 1121 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1122 sysfilt_ops[~filt].for_fop == NULL) 1123 error = EINVAL; 1124 else if (sysfilt_ops[~filt].for_refcnt != 0) 1125 error = EBUSY; 1126 else { 1127 sysfilt_ops[~filt].for_fop = &null_filtops; 1128 sysfilt_ops[~filt].for_refcnt = 0; 1129 } 1130 mtx_unlock(&filterops_lock); 1131 1132 return error; 1133 } 1134 1135 static struct filterops * 1136 kqueue_fo_find(int filt) 1137 { 1138 1139 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1140 return NULL; 1141 1142 if (sysfilt_ops[~filt].for_nolock) 1143 return sysfilt_ops[~filt].for_fop; 1144 1145 mtx_lock(&filterops_lock); 1146 sysfilt_ops[~filt].for_refcnt++; 1147 if (sysfilt_ops[~filt].for_fop == NULL) 1148 sysfilt_ops[~filt].for_fop = &null_filtops; 1149 mtx_unlock(&filterops_lock); 1150 1151 return sysfilt_ops[~filt].for_fop; 1152 } 1153 1154 static void 1155 kqueue_fo_release(int filt) 1156 { 1157 1158 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1159 return; 1160 1161 if (sysfilt_ops[~filt].for_nolock) 1162 return; 1163 1164 mtx_lock(&filterops_lock); 1165 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1166 ("filter object refcount not valid on release")); 1167 sysfilt_ops[~filt].for_refcnt--; 1168 mtx_unlock(&filterops_lock); 1169 } 1170 1171 /* 1172 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1173 * influence if memory allocation should wait. Make sure it is 0 if you 1174 * hold any mutexes. 1175 */ 1176 static int 1177 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1178 { 1179 struct filterops *fops; 1180 struct file *fp; 1181 struct knote *kn, *tkn; 1182 struct knlist *knl; 1183 cap_rights_t rights; 1184 int error, filt, event; 1185 int haskqglobal, filedesc_unlock; 1186 1187 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1188 return (EINVAL); 1189 1190 fp = NULL; 1191 kn = NULL; 1192 knl = NULL; 1193 error = 0; 1194 haskqglobal = 0; 1195 filedesc_unlock = 0; 1196 1197 filt = kev->filter; 1198 fops = kqueue_fo_find(filt); 1199 if (fops == NULL) 1200 return EINVAL; 1201 1202 if (kev->flags & EV_ADD) { 1203 /* 1204 * Prevent waiting with locks. Non-sleepable 1205 * allocation failures are handled in the loop, only 1206 * if the spare knote appears to be actually required. 1207 */ 1208 tkn = knote_alloc(waitok); 1209 } else { 1210 tkn = NULL; 1211 } 1212 1213 findkn: 1214 if (fops->f_isfd) { 1215 KASSERT(td != NULL, ("td is NULL")); 1216 if (kev->ident > INT_MAX) 1217 error = EBADF; 1218 else 1219 error = fget(td, kev->ident, 1220 cap_rights_init(&rights, CAP_EVENT), &fp); 1221 if (error) 1222 goto done; 1223 1224 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1225 kev->ident, 0) != 0) { 1226 /* try again */ 1227 fdrop(fp, td); 1228 fp = NULL; 1229 error = kqueue_expand(kq, fops, kev->ident, waitok); 1230 if (error) 1231 goto done; 1232 goto findkn; 1233 } 1234 1235 if (fp->f_type == DTYPE_KQUEUE) { 1236 /* 1237 * If we add some intelligence about what we are doing, 1238 * we should be able to support events on ourselves. 1239 * We need to know when we are doing this to prevent 1240 * getting both the knlist lock and the kq lock since 1241 * they are the same thing. 1242 */ 1243 if (fp->f_data == kq) { 1244 error = EINVAL; 1245 goto done; 1246 } 1247 1248 /* 1249 * Pre-lock the filedesc before the global 1250 * lock mutex, see the comment in 1251 * kqueue_close(). 1252 */ 1253 FILEDESC_XLOCK(td->td_proc->p_fd); 1254 filedesc_unlock = 1; 1255 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1256 } 1257 1258 KQ_LOCK(kq); 1259 if (kev->ident < kq->kq_knlistsize) { 1260 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1261 if (kev->filter == kn->kn_filter) 1262 break; 1263 } 1264 } else { 1265 if ((kev->flags & EV_ADD) == EV_ADD) 1266 kqueue_expand(kq, fops, kev->ident, waitok); 1267 1268 KQ_LOCK(kq); 1269 1270 /* 1271 * If possible, find an existing knote to use for this kevent. 1272 */ 1273 if (kev->filter == EVFILT_PROC && 1274 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1275 /* This is an internal creation of a process tracking 1276 * note. Don't attempt to coalesce this with an 1277 * existing note. 1278 */ 1279 ; 1280 } else if (kq->kq_knhashmask != 0) { 1281 struct klist *list; 1282 1283 list = &kq->kq_knhash[ 1284 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1285 SLIST_FOREACH(kn, list, kn_link) 1286 if (kev->ident == kn->kn_id && 1287 kev->filter == kn->kn_filter) 1288 break; 1289 } 1290 } 1291 1292 /* knote is in the process of changing, wait for it to stabilize. */ 1293 if (kn != NULL && kn_in_flux(kn)) { 1294 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1295 if (filedesc_unlock) { 1296 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1297 filedesc_unlock = 0; 1298 } 1299 kq->kq_state |= KQ_FLUXWAIT; 1300 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1301 if (fp != NULL) { 1302 fdrop(fp, td); 1303 fp = NULL; 1304 } 1305 goto findkn; 1306 } 1307 1308 /* 1309 * kn now contains the matching knote, or NULL if no match 1310 */ 1311 if (kn == NULL) { 1312 if (kev->flags & EV_ADD) { 1313 kn = tkn; 1314 tkn = NULL; 1315 if (kn == NULL) { 1316 KQ_UNLOCK(kq); 1317 error = ENOMEM; 1318 goto done; 1319 } 1320 kn->kn_fp = fp; 1321 kn->kn_kq = kq; 1322 kn->kn_fop = fops; 1323 /* 1324 * apply reference counts to knote structure, and 1325 * do not release it at the end of this routine. 1326 */ 1327 fops = NULL; 1328 fp = NULL; 1329 1330 kn->kn_sfflags = kev->fflags; 1331 kn->kn_sdata = kev->data; 1332 kev->fflags = 0; 1333 kev->data = 0; 1334 kn->kn_kevent = *kev; 1335 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1336 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1337 kn->kn_status = KN_DETACHED; 1338 kn_enter_flux(kn); 1339 1340 error = knote_attach(kn, kq); 1341 KQ_UNLOCK(kq); 1342 if (error != 0) { 1343 tkn = kn; 1344 goto done; 1345 } 1346 1347 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1348 knote_drop_detached(kn, td); 1349 goto done; 1350 } 1351 knl = kn_list_lock(kn); 1352 goto done_ev_add; 1353 } else { 1354 /* No matching knote and the EV_ADD flag is not set. */ 1355 KQ_UNLOCK(kq); 1356 error = ENOENT; 1357 goto done; 1358 } 1359 } 1360 1361 if (kev->flags & EV_DELETE) { 1362 kn_enter_flux(kn); 1363 KQ_UNLOCK(kq); 1364 knote_drop(kn, td); 1365 goto done; 1366 } 1367 1368 if (kev->flags & EV_FORCEONESHOT) { 1369 kn->kn_flags |= EV_ONESHOT; 1370 KNOTE_ACTIVATE(kn, 1); 1371 } 1372 1373 /* 1374 * The user may change some filter values after the initial EV_ADD, 1375 * but doing so will not reset any filter which has already been 1376 * triggered. 1377 */ 1378 kn->kn_status |= KN_SCAN; 1379 kn_enter_flux(kn); 1380 KQ_UNLOCK(kq); 1381 knl = kn_list_lock(kn); 1382 kn->kn_kevent.udata = kev->udata; 1383 if (!fops->f_isfd && fops->f_touch != NULL) { 1384 fops->f_touch(kn, kev, EVENT_REGISTER); 1385 } else { 1386 kn->kn_sfflags = kev->fflags; 1387 kn->kn_sdata = kev->data; 1388 } 1389 1390 /* 1391 * We can get here with kn->kn_knlist == NULL. This can happen when 1392 * the initial attach event decides that the event is "completed" 1393 * already. i.e. filt_procattach is called on a zombie process. It 1394 * will call filt_proc which will remove it from the list, and NULL 1395 * kn_knlist. 1396 */ 1397 done_ev_add: 1398 if ((kev->flags & EV_ENABLE) != 0) 1399 kn->kn_status &= ~KN_DISABLED; 1400 else if ((kev->flags & EV_DISABLE) != 0) 1401 kn->kn_status |= KN_DISABLED; 1402 1403 if ((kn->kn_status & KN_DISABLED) == 0) 1404 event = kn->kn_fop->f_event(kn, 0); 1405 else 1406 event = 0; 1407 1408 KQ_LOCK(kq); 1409 if (event) 1410 kn->kn_status |= KN_ACTIVE; 1411 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1412 KN_ACTIVE) 1413 knote_enqueue(kn); 1414 kn->kn_status &= ~KN_SCAN; 1415 kn_leave_flux(kn); 1416 kn_list_unlock(knl); 1417 KQ_UNLOCK_FLUX(kq); 1418 1419 done: 1420 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1421 if (filedesc_unlock) 1422 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1423 if (fp != NULL) 1424 fdrop(fp, td); 1425 knote_free(tkn); 1426 if (fops != NULL) 1427 kqueue_fo_release(filt); 1428 return (error); 1429 } 1430 1431 static int 1432 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1433 { 1434 int error; 1435 struct kqueue *kq; 1436 1437 error = 0; 1438 1439 kq = fp->f_data; 1440 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1441 return (EBADF); 1442 *kqp = kq; 1443 KQ_LOCK(kq); 1444 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1445 KQ_UNLOCK(kq); 1446 return (EBADF); 1447 } 1448 kq->kq_refcnt++; 1449 KQ_UNLOCK(kq); 1450 1451 return error; 1452 } 1453 1454 static void 1455 kqueue_release(struct kqueue *kq, int locked) 1456 { 1457 if (locked) 1458 KQ_OWNED(kq); 1459 else 1460 KQ_LOCK(kq); 1461 kq->kq_refcnt--; 1462 if (kq->kq_refcnt == 1) 1463 wakeup(&kq->kq_refcnt); 1464 if (!locked) 1465 KQ_UNLOCK(kq); 1466 } 1467 1468 static void 1469 kqueue_schedtask(struct kqueue *kq) 1470 { 1471 1472 KQ_OWNED(kq); 1473 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1474 ("scheduling kqueue task while draining")); 1475 1476 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1477 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1478 kq->kq_state |= KQ_TASKSCHED; 1479 } 1480 } 1481 1482 /* 1483 * Expand the kq to make sure we have storage for fops/ident pair. 1484 * 1485 * Return 0 on success (or no work necessary), return errno on failure. 1486 * 1487 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1488 * If kqueue_register is called from a non-fd context, there usually/should 1489 * be no locks held. 1490 */ 1491 static int 1492 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1493 int waitok) 1494 { 1495 struct klist *list, *tmp_knhash, *to_free; 1496 u_long tmp_knhashmask; 1497 int size; 1498 int fd; 1499 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1500 1501 KQ_NOTOWNED(kq); 1502 1503 to_free = NULL; 1504 if (fops->f_isfd) { 1505 fd = ident; 1506 if (kq->kq_knlistsize <= fd) { 1507 size = kq->kq_knlistsize; 1508 while (size <= fd) 1509 size += KQEXTENT; 1510 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1511 if (list == NULL) 1512 return ENOMEM; 1513 KQ_LOCK(kq); 1514 if (kq->kq_knlistsize > fd) { 1515 to_free = list; 1516 list = NULL; 1517 } else { 1518 if (kq->kq_knlist != NULL) { 1519 bcopy(kq->kq_knlist, list, 1520 kq->kq_knlistsize * sizeof(*list)); 1521 to_free = kq->kq_knlist; 1522 kq->kq_knlist = NULL; 1523 } 1524 bzero((caddr_t)list + 1525 kq->kq_knlistsize * sizeof(*list), 1526 (size - kq->kq_knlistsize) * sizeof(*list)); 1527 kq->kq_knlistsize = size; 1528 kq->kq_knlist = list; 1529 } 1530 KQ_UNLOCK(kq); 1531 } 1532 } else { 1533 if (kq->kq_knhashmask == 0) { 1534 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1535 &tmp_knhashmask); 1536 if (tmp_knhash == NULL) 1537 return ENOMEM; 1538 KQ_LOCK(kq); 1539 if (kq->kq_knhashmask == 0) { 1540 kq->kq_knhash = tmp_knhash; 1541 kq->kq_knhashmask = tmp_knhashmask; 1542 } else { 1543 to_free = tmp_knhash; 1544 } 1545 KQ_UNLOCK(kq); 1546 } 1547 } 1548 free(to_free, M_KQUEUE); 1549 1550 KQ_NOTOWNED(kq); 1551 return 0; 1552 } 1553 1554 static void 1555 kqueue_task(void *arg, int pending) 1556 { 1557 struct kqueue *kq; 1558 int haskqglobal; 1559 1560 haskqglobal = 0; 1561 kq = arg; 1562 1563 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1564 KQ_LOCK(kq); 1565 1566 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1567 1568 kq->kq_state &= ~KQ_TASKSCHED; 1569 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1570 wakeup(&kq->kq_state); 1571 } 1572 KQ_UNLOCK(kq); 1573 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1574 } 1575 1576 /* 1577 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1578 * We treat KN_MARKER knotes as if they are in flux. 1579 */ 1580 static int 1581 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1582 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1583 { 1584 struct kevent *kevp; 1585 struct knote *kn, *marker; 1586 struct knlist *knl; 1587 sbintime_t asbt, rsbt; 1588 int count, error, haskqglobal, influx, nkev, touch; 1589 1590 count = maxevents; 1591 nkev = 0; 1592 error = 0; 1593 haskqglobal = 0; 1594 1595 if (maxevents == 0) 1596 goto done_nl; 1597 1598 rsbt = 0; 1599 if (tsp != NULL) { 1600 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1601 tsp->tv_nsec >= 1000000000) { 1602 error = EINVAL; 1603 goto done_nl; 1604 } 1605 if (timespecisset(tsp)) { 1606 if (tsp->tv_sec <= INT32_MAX) { 1607 rsbt = tstosbt(*tsp); 1608 if (TIMESEL(&asbt, rsbt)) 1609 asbt += tc_tick_sbt; 1610 if (asbt <= SBT_MAX - rsbt) 1611 asbt += rsbt; 1612 else 1613 asbt = 0; 1614 rsbt >>= tc_precexp; 1615 } else 1616 asbt = 0; 1617 } else 1618 asbt = -1; 1619 } else 1620 asbt = 0; 1621 marker = knote_alloc(1); 1622 marker->kn_status = KN_MARKER; 1623 KQ_LOCK(kq); 1624 1625 retry: 1626 kevp = keva; 1627 if (kq->kq_count == 0) { 1628 if (asbt == -1) { 1629 error = EWOULDBLOCK; 1630 } else { 1631 kq->kq_state |= KQ_SLEEP; 1632 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1633 "kqread", asbt, rsbt, C_ABSOLUTE); 1634 } 1635 if (error == 0) 1636 goto retry; 1637 /* don't restart after signals... */ 1638 if (error == ERESTART) 1639 error = EINTR; 1640 else if (error == EWOULDBLOCK) 1641 error = 0; 1642 goto done; 1643 } 1644 1645 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1646 influx = 0; 1647 while (count) { 1648 KQ_OWNED(kq); 1649 kn = TAILQ_FIRST(&kq->kq_head); 1650 1651 if ((kn->kn_status == KN_MARKER && kn != marker) || 1652 kn_in_flux(kn)) { 1653 if (influx) { 1654 influx = 0; 1655 KQ_FLUX_WAKEUP(kq); 1656 } 1657 kq->kq_state |= KQ_FLUXWAIT; 1658 error = msleep(kq, &kq->kq_lock, PSOCK, 1659 "kqflxwt", 0); 1660 continue; 1661 } 1662 1663 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1664 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1665 kn->kn_status &= ~KN_QUEUED; 1666 kq->kq_count--; 1667 continue; 1668 } 1669 if (kn == marker) { 1670 KQ_FLUX_WAKEUP(kq); 1671 if (count == maxevents) 1672 goto retry; 1673 goto done; 1674 } 1675 KASSERT(!kn_in_flux(kn), 1676 ("knote %p is unexpectedly in flux", kn)); 1677 1678 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1679 kn->kn_status &= ~KN_QUEUED; 1680 kn_enter_flux(kn); 1681 kq->kq_count--; 1682 KQ_UNLOCK(kq); 1683 /* 1684 * We don't need to lock the list since we've 1685 * marked it as in flux. 1686 */ 1687 knote_drop(kn, td); 1688 KQ_LOCK(kq); 1689 continue; 1690 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1691 kn->kn_status &= ~KN_QUEUED; 1692 kn_enter_flux(kn); 1693 kq->kq_count--; 1694 KQ_UNLOCK(kq); 1695 /* 1696 * We don't need to lock the list since we've 1697 * marked the knote as being in flux. 1698 */ 1699 *kevp = kn->kn_kevent; 1700 knote_drop(kn, td); 1701 KQ_LOCK(kq); 1702 kn = NULL; 1703 } else { 1704 kn->kn_status |= KN_SCAN; 1705 kn_enter_flux(kn); 1706 KQ_UNLOCK(kq); 1707 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1708 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1709 knl = kn_list_lock(kn); 1710 if (kn->kn_fop->f_event(kn, 0) == 0) { 1711 KQ_LOCK(kq); 1712 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1713 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE | 1714 KN_SCAN); 1715 kn_leave_flux(kn); 1716 kq->kq_count--; 1717 kn_list_unlock(knl); 1718 influx = 1; 1719 continue; 1720 } 1721 touch = (!kn->kn_fop->f_isfd && 1722 kn->kn_fop->f_touch != NULL); 1723 if (touch) 1724 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1725 else 1726 *kevp = kn->kn_kevent; 1727 KQ_LOCK(kq); 1728 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1729 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1730 /* 1731 * Manually clear knotes who weren't 1732 * 'touch'ed. 1733 */ 1734 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1735 kn->kn_data = 0; 1736 kn->kn_fflags = 0; 1737 } 1738 if (kn->kn_flags & EV_DISPATCH) 1739 kn->kn_status |= KN_DISABLED; 1740 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1741 kq->kq_count--; 1742 } else 1743 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1744 1745 kn->kn_status &= ~KN_SCAN; 1746 kn_leave_flux(kn); 1747 kn_list_unlock(knl); 1748 influx = 1; 1749 } 1750 1751 /* we are returning a copy to the user */ 1752 kevp++; 1753 nkev++; 1754 count--; 1755 1756 if (nkev == KQ_NEVENTS) { 1757 influx = 0; 1758 KQ_UNLOCK_FLUX(kq); 1759 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1760 nkev = 0; 1761 kevp = keva; 1762 KQ_LOCK(kq); 1763 if (error) 1764 break; 1765 } 1766 } 1767 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1768 done: 1769 KQ_OWNED(kq); 1770 KQ_UNLOCK_FLUX(kq); 1771 knote_free(marker); 1772 done_nl: 1773 KQ_NOTOWNED(kq); 1774 if (nkev != 0) 1775 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1776 td->td_retval[0] = maxevents - count; 1777 return (error); 1778 } 1779 1780 /*ARGSUSED*/ 1781 static int 1782 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1783 struct ucred *active_cred, struct thread *td) 1784 { 1785 /* 1786 * Enabling sigio causes two major problems: 1787 * 1) infinite recursion: 1788 * Synopsys: kevent is being used to track signals and have FIOASYNC 1789 * set. On receipt of a signal this will cause a kqueue to recurse 1790 * into itself over and over. Sending the sigio causes the kqueue 1791 * to become ready, which in turn posts sigio again, forever. 1792 * Solution: this can be solved by setting a flag in the kqueue that 1793 * we have a SIGIO in progress. 1794 * 2) locking problems: 1795 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1796 * us above the proc and pgrp locks. 1797 * Solution: Post a signal using an async mechanism, being sure to 1798 * record a generation count in the delivery so that we do not deliver 1799 * a signal to the wrong process. 1800 * 1801 * Note, these two mechanisms are somewhat mutually exclusive! 1802 */ 1803 #if 0 1804 struct kqueue *kq; 1805 1806 kq = fp->f_data; 1807 switch (cmd) { 1808 case FIOASYNC: 1809 if (*(int *)data) { 1810 kq->kq_state |= KQ_ASYNC; 1811 } else { 1812 kq->kq_state &= ~KQ_ASYNC; 1813 } 1814 return (0); 1815 1816 case FIOSETOWN: 1817 return (fsetown(*(int *)data, &kq->kq_sigio)); 1818 1819 case FIOGETOWN: 1820 *(int *)data = fgetown(&kq->kq_sigio); 1821 return (0); 1822 } 1823 #endif 1824 1825 return (ENOTTY); 1826 } 1827 1828 /*ARGSUSED*/ 1829 static int 1830 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1831 struct thread *td) 1832 { 1833 struct kqueue *kq; 1834 int revents = 0; 1835 int error; 1836 1837 if ((error = kqueue_acquire(fp, &kq))) 1838 return POLLERR; 1839 1840 KQ_LOCK(kq); 1841 if (events & (POLLIN | POLLRDNORM)) { 1842 if (kq->kq_count) { 1843 revents |= events & (POLLIN | POLLRDNORM); 1844 } else { 1845 selrecord(td, &kq->kq_sel); 1846 if (SEL_WAITING(&kq->kq_sel)) 1847 kq->kq_state |= KQ_SEL; 1848 } 1849 } 1850 kqueue_release(kq, 1); 1851 KQ_UNLOCK(kq); 1852 return (revents); 1853 } 1854 1855 /*ARGSUSED*/ 1856 static int 1857 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1858 struct thread *td) 1859 { 1860 1861 bzero((void *)st, sizeof *st); 1862 /* 1863 * We no longer return kq_count because the unlocked value is useless. 1864 * If you spent all this time getting the count, why not spend your 1865 * syscall better by calling kevent? 1866 * 1867 * XXX - This is needed for libc_r. 1868 */ 1869 st->st_mode = S_IFIFO; 1870 return (0); 1871 } 1872 1873 static void 1874 kqueue_drain(struct kqueue *kq, struct thread *td) 1875 { 1876 struct knote *kn; 1877 int i; 1878 1879 KQ_LOCK(kq); 1880 1881 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1882 ("kqueue already closing")); 1883 kq->kq_state |= KQ_CLOSING; 1884 if (kq->kq_refcnt > 1) 1885 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1886 1887 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1888 1889 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1890 ("kqueue's knlist not empty")); 1891 1892 for (i = 0; i < kq->kq_knlistsize; i++) { 1893 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1894 if (kn_in_flux(kn)) { 1895 kq->kq_state |= KQ_FLUXWAIT; 1896 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1897 continue; 1898 } 1899 kn_enter_flux(kn); 1900 KQ_UNLOCK(kq); 1901 knote_drop(kn, td); 1902 KQ_LOCK(kq); 1903 } 1904 } 1905 if (kq->kq_knhashmask != 0) { 1906 for (i = 0; i <= kq->kq_knhashmask; i++) { 1907 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1908 if (kn_in_flux(kn)) { 1909 kq->kq_state |= KQ_FLUXWAIT; 1910 msleep(kq, &kq->kq_lock, PSOCK, 1911 "kqclo2", 0); 1912 continue; 1913 } 1914 kn_enter_flux(kn); 1915 KQ_UNLOCK(kq); 1916 knote_drop(kn, td); 1917 KQ_LOCK(kq); 1918 } 1919 } 1920 } 1921 1922 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1923 kq->kq_state |= KQ_TASKDRAIN; 1924 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1925 } 1926 1927 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1928 selwakeuppri(&kq->kq_sel, PSOCK); 1929 if (!SEL_WAITING(&kq->kq_sel)) 1930 kq->kq_state &= ~KQ_SEL; 1931 } 1932 1933 KQ_UNLOCK(kq); 1934 } 1935 1936 static void 1937 kqueue_destroy(struct kqueue *kq) 1938 { 1939 1940 KASSERT(kq->kq_fdp == NULL, 1941 ("kqueue still attached to a file descriptor")); 1942 seldrain(&kq->kq_sel); 1943 knlist_destroy(&kq->kq_sel.si_note); 1944 mtx_destroy(&kq->kq_lock); 1945 1946 if (kq->kq_knhash != NULL) 1947 free(kq->kq_knhash, M_KQUEUE); 1948 if (kq->kq_knlist != NULL) 1949 free(kq->kq_knlist, M_KQUEUE); 1950 1951 funsetown(&kq->kq_sigio); 1952 } 1953 1954 /*ARGSUSED*/ 1955 static int 1956 kqueue_close(struct file *fp, struct thread *td) 1957 { 1958 struct kqueue *kq = fp->f_data; 1959 struct filedesc *fdp; 1960 int error; 1961 int filedesc_unlock; 1962 1963 if ((error = kqueue_acquire(fp, &kq))) 1964 return error; 1965 kqueue_drain(kq, td); 1966 1967 /* 1968 * We could be called due to the knote_drop() doing fdrop(), 1969 * called from kqueue_register(). In this case the global 1970 * lock is owned, and filedesc sx is locked before, to not 1971 * take the sleepable lock after non-sleepable. 1972 */ 1973 fdp = kq->kq_fdp; 1974 kq->kq_fdp = NULL; 1975 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1976 FILEDESC_XLOCK(fdp); 1977 filedesc_unlock = 1; 1978 } else 1979 filedesc_unlock = 0; 1980 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1981 if (filedesc_unlock) 1982 FILEDESC_XUNLOCK(fdp); 1983 1984 kqueue_destroy(kq); 1985 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1986 crfree(kq->kq_cred); 1987 free(kq, M_KQUEUE); 1988 fp->f_data = NULL; 1989 1990 return (0); 1991 } 1992 1993 static int 1994 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 1995 { 1996 1997 kif->kf_type = KF_TYPE_KQUEUE; 1998 return (0); 1999 } 2000 2001 static void 2002 kqueue_wakeup(struct kqueue *kq) 2003 { 2004 KQ_OWNED(kq); 2005 2006 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 2007 kq->kq_state &= ~KQ_SLEEP; 2008 wakeup(kq); 2009 } 2010 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 2011 selwakeuppri(&kq->kq_sel, PSOCK); 2012 if (!SEL_WAITING(&kq->kq_sel)) 2013 kq->kq_state &= ~KQ_SEL; 2014 } 2015 if (!knlist_empty(&kq->kq_sel.si_note)) 2016 kqueue_schedtask(kq); 2017 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 2018 pgsigio(&kq->kq_sigio, SIGIO, 0); 2019 } 2020 } 2021 2022 /* 2023 * Walk down a list of knotes, activating them if their event has triggered. 2024 * 2025 * There is a possibility to optimize in the case of one kq watching another. 2026 * Instead of scheduling a task to wake it up, you could pass enough state 2027 * down the chain to make up the parent kqueue. Make this code functional 2028 * first. 2029 */ 2030 void 2031 knote(struct knlist *list, long hint, int lockflags) 2032 { 2033 struct kqueue *kq; 2034 struct knote *kn, *tkn; 2035 int error; 2036 2037 if (list == NULL) 2038 return; 2039 2040 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2041 2042 if ((lockflags & KNF_LISTLOCKED) == 0) 2043 list->kl_lock(list->kl_lockarg); 2044 2045 /* 2046 * If we unlock the list lock (and enter influx), we can 2047 * eliminate the kqueue scheduling, but this will introduce 2048 * four lock/unlock's for each knote to test. Also, marker 2049 * would be needed to keep iteration position, since filters 2050 * or other threads could remove events. 2051 */ 2052 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2053 kq = kn->kn_kq; 2054 KQ_LOCK(kq); 2055 if (kn_in_flux(kn) && (kn->kn_status & KN_SCAN) == 0) { 2056 /* 2057 * Do not process the influx notes, except for 2058 * the influx coming from the kq unlock in the 2059 * kqueue_scan(). In the later case, we do 2060 * not interfere with the scan, since the code 2061 * fragment in kqueue_scan() locks the knlist, 2062 * and cannot proceed until we finished. 2063 */ 2064 KQ_UNLOCK(kq); 2065 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2066 kn_enter_flux(kn); 2067 KQ_UNLOCK(kq); 2068 error = kn->kn_fop->f_event(kn, hint); 2069 KQ_LOCK(kq); 2070 kn_leave_flux(kn); 2071 if (error) 2072 KNOTE_ACTIVATE(kn, 1); 2073 KQ_UNLOCK_FLUX(kq); 2074 } else { 2075 kn->kn_status |= KN_HASKQLOCK; 2076 if (kn->kn_fop->f_event(kn, hint)) 2077 KNOTE_ACTIVATE(kn, 1); 2078 kn->kn_status &= ~KN_HASKQLOCK; 2079 KQ_UNLOCK(kq); 2080 } 2081 } 2082 if ((lockflags & KNF_LISTLOCKED) == 0) 2083 list->kl_unlock(list->kl_lockarg); 2084 } 2085 2086 /* 2087 * add a knote to a knlist 2088 */ 2089 void 2090 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2091 { 2092 2093 KNL_ASSERT_LOCK(knl, islocked); 2094 KQ_NOTOWNED(kn->kn_kq); 2095 KASSERT(kn_in_flux(kn), ("knote %p not in flux", kn)); 2096 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2097 ("knote %p was not detached", kn)); 2098 if (!islocked) 2099 knl->kl_lock(knl->kl_lockarg); 2100 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2101 if (!islocked) 2102 knl->kl_unlock(knl->kl_lockarg); 2103 KQ_LOCK(kn->kn_kq); 2104 kn->kn_knlist = knl; 2105 kn->kn_status &= ~KN_DETACHED; 2106 KQ_UNLOCK(kn->kn_kq); 2107 } 2108 2109 static void 2110 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2111 int kqislocked) 2112 { 2113 2114 KASSERT(!kqislocked || knlislocked, ("kq locked w/o knl locked")); 2115 KNL_ASSERT_LOCK(knl, knlislocked); 2116 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2117 KASSERT(kqislocked || kn_in_flux(kn), ("knote %p not in flux", kn)); 2118 KASSERT((kn->kn_status & KN_DETACHED) == 0, 2119 ("knote %p was already detached", kn)); 2120 if (!knlislocked) 2121 knl->kl_lock(knl->kl_lockarg); 2122 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2123 kn->kn_knlist = NULL; 2124 if (!knlislocked) 2125 kn_list_unlock(knl); 2126 if (!kqislocked) 2127 KQ_LOCK(kn->kn_kq); 2128 kn->kn_status |= KN_DETACHED; 2129 if (!kqislocked) 2130 KQ_UNLOCK(kn->kn_kq); 2131 } 2132 2133 /* 2134 * remove knote from the specified knlist 2135 */ 2136 void 2137 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2138 { 2139 2140 knlist_remove_kq(knl, kn, islocked, 0); 2141 } 2142 2143 int 2144 knlist_empty(struct knlist *knl) 2145 { 2146 2147 KNL_ASSERT_LOCKED(knl); 2148 return (SLIST_EMPTY(&knl->kl_list)); 2149 } 2150 2151 static struct mtx knlist_lock; 2152 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2153 MTX_DEF); 2154 static void knlist_mtx_lock(void *arg); 2155 static void knlist_mtx_unlock(void *arg); 2156 2157 static void 2158 knlist_mtx_lock(void *arg) 2159 { 2160 2161 mtx_lock((struct mtx *)arg); 2162 } 2163 2164 static void 2165 knlist_mtx_unlock(void *arg) 2166 { 2167 2168 mtx_unlock((struct mtx *)arg); 2169 } 2170 2171 static void 2172 knlist_mtx_assert_locked(void *arg) 2173 { 2174 2175 mtx_assert((struct mtx *)arg, MA_OWNED); 2176 } 2177 2178 static void 2179 knlist_mtx_assert_unlocked(void *arg) 2180 { 2181 2182 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2183 } 2184 2185 static void 2186 knlist_rw_rlock(void *arg) 2187 { 2188 2189 rw_rlock((struct rwlock *)arg); 2190 } 2191 2192 static void 2193 knlist_rw_runlock(void *arg) 2194 { 2195 2196 rw_runlock((struct rwlock *)arg); 2197 } 2198 2199 static void 2200 knlist_rw_assert_locked(void *arg) 2201 { 2202 2203 rw_assert((struct rwlock *)arg, RA_LOCKED); 2204 } 2205 2206 static void 2207 knlist_rw_assert_unlocked(void *arg) 2208 { 2209 2210 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2211 } 2212 2213 void 2214 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2215 void (*kl_unlock)(void *), 2216 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2217 { 2218 2219 if (lock == NULL) 2220 knl->kl_lockarg = &knlist_lock; 2221 else 2222 knl->kl_lockarg = lock; 2223 2224 if (kl_lock == NULL) 2225 knl->kl_lock = knlist_mtx_lock; 2226 else 2227 knl->kl_lock = kl_lock; 2228 if (kl_unlock == NULL) 2229 knl->kl_unlock = knlist_mtx_unlock; 2230 else 2231 knl->kl_unlock = kl_unlock; 2232 if (kl_assert_locked == NULL) 2233 knl->kl_assert_locked = knlist_mtx_assert_locked; 2234 else 2235 knl->kl_assert_locked = kl_assert_locked; 2236 if (kl_assert_unlocked == NULL) 2237 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2238 else 2239 knl->kl_assert_unlocked = kl_assert_unlocked; 2240 2241 knl->kl_autodestroy = 0; 2242 SLIST_INIT(&knl->kl_list); 2243 } 2244 2245 void 2246 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2247 { 2248 2249 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2250 } 2251 2252 struct knlist * 2253 knlist_alloc(struct mtx *lock) 2254 { 2255 struct knlist *knl; 2256 2257 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2258 knlist_init_mtx(knl, lock); 2259 return (knl); 2260 } 2261 2262 void 2263 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2264 { 2265 2266 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2267 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2268 } 2269 2270 void 2271 knlist_destroy(struct knlist *knl) 2272 { 2273 2274 KASSERT(KNLIST_EMPTY(knl), 2275 ("destroying knlist %p with knotes on it", knl)); 2276 } 2277 2278 void 2279 knlist_detach(struct knlist *knl) 2280 { 2281 2282 KNL_ASSERT_LOCKED(knl); 2283 knl->kl_autodestroy = 1; 2284 if (knlist_empty(knl)) { 2285 knlist_destroy(knl); 2286 free(knl, M_KQUEUE); 2287 } 2288 } 2289 2290 /* 2291 * Even if we are locked, we may need to drop the lock to allow any influx 2292 * knotes time to "settle". 2293 */ 2294 void 2295 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2296 { 2297 struct knote *kn, *kn2; 2298 struct kqueue *kq; 2299 2300 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2301 if (islocked) 2302 KNL_ASSERT_LOCKED(knl); 2303 else { 2304 KNL_ASSERT_UNLOCKED(knl); 2305 again: /* need to reacquire lock since we have dropped it */ 2306 knl->kl_lock(knl->kl_lockarg); 2307 } 2308 2309 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2310 kq = kn->kn_kq; 2311 KQ_LOCK(kq); 2312 if (kn_in_flux(kn)) { 2313 KQ_UNLOCK(kq); 2314 continue; 2315 } 2316 knlist_remove_kq(knl, kn, 1, 1); 2317 if (killkn) { 2318 kn_enter_flux(kn); 2319 KQ_UNLOCK(kq); 2320 knote_drop_detached(kn, td); 2321 } else { 2322 /* Make sure cleared knotes disappear soon */ 2323 kn->kn_flags |= EV_EOF | EV_ONESHOT; 2324 KQ_UNLOCK(kq); 2325 } 2326 kq = NULL; 2327 } 2328 2329 if (!SLIST_EMPTY(&knl->kl_list)) { 2330 /* there are still in flux knotes remaining */ 2331 kn = SLIST_FIRST(&knl->kl_list); 2332 kq = kn->kn_kq; 2333 KQ_LOCK(kq); 2334 KASSERT(kn_in_flux(kn), ("knote removed w/o list lock")); 2335 knl->kl_unlock(knl->kl_lockarg); 2336 kq->kq_state |= KQ_FLUXWAIT; 2337 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2338 kq = NULL; 2339 goto again; 2340 } 2341 2342 if (islocked) 2343 KNL_ASSERT_LOCKED(knl); 2344 else { 2345 knl->kl_unlock(knl->kl_lockarg); 2346 KNL_ASSERT_UNLOCKED(knl); 2347 } 2348 } 2349 2350 /* 2351 * Remove all knotes referencing a specified fd must be called with FILEDESC 2352 * lock. This prevents a race where a new fd comes along and occupies the 2353 * entry and we attach a knote to the fd. 2354 */ 2355 void 2356 knote_fdclose(struct thread *td, int fd) 2357 { 2358 struct filedesc *fdp = td->td_proc->p_fd; 2359 struct kqueue *kq; 2360 struct knote *kn; 2361 int influx; 2362 2363 FILEDESC_XLOCK_ASSERT(fdp); 2364 2365 /* 2366 * We shouldn't have to worry about new kevents appearing on fd 2367 * since filedesc is locked. 2368 */ 2369 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2370 KQ_LOCK(kq); 2371 2372 again: 2373 influx = 0; 2374 while (kq->kq_knlistsize > fd && 2375 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2376 if (kn_in_flux(kn)) { 2377 /* someone else might be waiting on our knote */ 2378 if (influx) 2379 wakeup(kq); 2380 kq->kq_state |= KQ_FLUXWAIT; 2381 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2382 goto again; 2383 } 2384 kn_enter_flux(kn); 2385 KQ_UNLOCK(kq); 2386 influx = 1; 2387 knote_drop(kn, td); 2388 KQ_LOCK(kq); 2389 } 2390 KQ_UNLOCK_FLUX(kq); 2391 } 2392 } 2393 2394 static int 2395 knote_attach(struct knote *kn, struct kqueue *kq) 2396 { 2397 struct klist *list; 2398 2399 KASSERT(kn_in_flux(kn), ("knote %p not marked influx", kn)); 2400 KQ_OWNED(kq); 2401 2402 if (kn->kn_fop->f_isfd) { 2403 if (kn->kn_id >= kq->kq_knlistsize) 2404 return (ENOMEM); 2405 list = &kq->kq_knlist[kn->kn_id]; 2406 } else { 2407 if (kq->kq_knhash == NULL) 2408 return (ENOMEM); 2409 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2410 } 2411 SLIST_INSERT_HEAD(list, kn, kn_link); 2412 return (0); 2413 } 2414 2415 static void 2416 knote_drop(struct knote *kn, struct thread *td) 2417 { 2418 2419 if ((kn->kn_status & KN_DETACHED) == 0) 2420 kn->kn_fop->f_detach(kn); 2421 knote_drop_detached(kn, td); 2422 } 2423 2424 static void 2425 knote_drop_detached(struct knote *kn, struct thread *td) 2426 { 2427 struct kqueue *kq; 2428 struct klist *list; 2429 2430 kq = kn->kn_kq; 2431 2432 KASSERT((kn->kn_status & KN_DETACHED) != 0, 2433 ("knote %p still attached", kn)); 2434 KQ_NOTOWNED(kq); 2435 2436 KQ_LOCK(kq); 2437 KASSERT(kn->kn_influx == 1, 2438 ("knote_drop called on %p with influx %d", kn, kn->kn_influx)); 2439 2440 if (kn->kn_fop->f_isfd) 2441 list = &kq->kq_knlist[kn->kn_id]; 2442 else 2443 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2444 2445 if (!SLIST_EMPTY(list)) 2446 SLIST_REMOVE(list, kn, knote, kn_link); 2447 if (kn->kn_status & KN_QUEUED) 2448 knote_dequeue(kn); 2449 KQ_UNLOCK_FLUX(kq); 2450 2451 if (kn->kn_fop->f_isfd) { 2452 fdrop(kn->kn_fp, td); 2453 kn->kn_fp = NULL; 2454 } 2455 kqueue_fo_release(kn->kn_kevent.filter); 2456 kn->kn_fop = NULL; 2457 knote_free(kn); 2458 } 2459 2460 static void 2461 knote_enqueue(struct knote *kn) 2462 { 2463 struct kqueue *kq = kn->kn_kq; 2464 2465 KQ_OWNED(kn->kn_kq); 2466 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2467 2468 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2469 kn->kn_status |= KN_QUEUED; 2470 kq->kq_count++; 2471 kqueue_wakeup(kq); 2472 } 2473 2474 static void 2475 knote_dequeue(struct knote *kn) 2476 { 2477 struct kqueue *kq = kn->kn_kq; 2478 2479 KQ_OWNED(kn->kn_kq); 2480 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2481 2482 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2483 kn->kn_status &= ~KN_QUEUED; 2484 kq->kq_count--; 2485 } 2486 2487 static void 2488 knote_init(void) 2489 { 2490 2491 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2492 NULL, NULL, UMA_ALIGN_PTR, 0); 2493 } 2494 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2495 2496 static struct knote * 2497 knote_alloc(int waitok) 2498 { 2499 2500 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | 2501 M_ZERO)); 2502 } 2503 2504 static void 2505 knote_free(struct knote *kn) 2506 { 2507 2508 uma_zfree(knote_zone, kn); 2509 } 2510 2511 /* 2512 * Register the kev w/ the kq specified by fd. 2513 */ 2514 int 2515 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2516 { 2517 struct kqueue *kq; 2518 struct file *fp; 2519 cap_rights_t rights; 2520 int error; 2521 2522 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2523 if (error != 0) 2524 return (error); 2525 if ((error = kqueue_acquire(fp, &kq)) != 0) 2526 goto noacquire; 2527 2528 error = kqueue_register(kq, kev, td, waitok); 2529 kqueue_release(kq, 0); 2530 2531 noacquire: 2532 fdrop(fp, td); 2533 return (error); 2534 } 2535