Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_event.c
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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: releng/11.2/sys/kern/kern_event.c 342899 2019-01-09 18:57:38Z emaste $"); 31 32 #include "opt_ktrace.h" 33 #include "opt_kqueue.h" 34 35 #include <sys/param.h> 36 #include <sys/systm.h> 37 #include <sys/capsicum.h> 38 #include <sys/kernel.h> 39 #include <sys/lock.h> 40 #include <sys/mutex.h> 41 #include <sys/rwlock.h> 42 #include <sys/proc.h> 43 #include <sys/malloc.h> 44 #include <sys/unistd.h> 45 #include <sys/file.h> 46 #include <sys/filedesc.h> 47 #include <sys/filio.h> 48 #include <sys/fcntl.h> 49 #include <sys/kthread.h> 50 #include <sys/selinfo.h> 51 #include <sys/queue.h> 52 #include <sys/event.h> 53 #include <sys/eventvar.h> 54 #include <sys/poll.h> 55 #include <sys/protosw.h> 56 #include <sys/resourcevar.h> 57 #include <sys/sigio.h> 58 #include <sys/signalvar.h> 59 #include <sys/socket.h> 60 #include <sys/socketvar.h> 61 #include <sys/stat.h> 62 #include <sys/sysctl.h> 63 #include <sys/sysproto.h> 64 #include <sys/syscallsubr.h> 65 #include <sys/taskqueue.h> 66 #include <sys/uio.h> 67 #include <sys/user.h> 68 #ifdef KTRACE 69 #include <sys/ktrace.h> 70 #endif 71 #include <machine/atomic.h> 72 73 #include <vm/uma.h> 74 75 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 76 77 /* 78 * This lock is used if multiple kq locks are required. This possibly 79 * should be made into a per proc lock. 80 */ 81 static struct mtx kq_global; 82 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 83 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 84 if (!haslck) \ 85 mtx_lock(lck); \ 86 haslck = 1; \ 87 } while (0) 88 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 89 if (haslck) \ 90 mtx_unlock(lck); \ 91 haslck = 0; \ 92 } while (0) 93 94 TASKQUEUE_DEFINE_THREAD(kqueue_ctx); 95 96 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 97 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 98 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 99 struct thread *td, int waitok); 100 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 101 static void kqueue_release(struct kqueue *kq, int locked); 102 static void kqueue_destroy(struct kqueue *kq); 103 static void kqueue_drain(struct kqueue *kq, struct thread *td); 104 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 105 uintptr_t ident, int waitok); 106 static void kqueue_task(void *arg, int pending); 107 static int kqueue_scan(struct kqueue *kq, int maxevents, 108 struct kevent_copyops *k_ops, 109 const struct timespec *timeout, 110 struct kevent *keva, struct thread *td); 111 static void kqueue_wakeup(struct kqueue *kq); 112 static struct filterops *kqueue_fo_find(int filt); 113 static void kqueue_fo_release(int filt); 114 115 static fo_ioctl_t kqueue_ioctl; 116 static fo_poll_t kqueue_poll; 117 static fo_kqfilter_t kqueue_kqfilter; 118 static fo_stat_t kqueue_stat; 119 static fo_close_t kqueue_close; 120 static fo_fill_kinfo_t kqueue_fill_kinfo; 121 122 static struct fileops kqueueops = { 123 .fo_read = invfo_rdwr, 124 .fo_write = invfo_rdwr, 125 .fo_truncate = invfo_truncate, 126 .fo_ioctl = kqueue_ioctl, 127 .fo_poll = kqueue_poll, 128 .fo_kqfilter = kqueue_kqfilter, 129 .fo_stat = kqueue_stat, 130 .fo_close = kqueue_close, 131 .fo_chmod = invfo_chmod, 132 .fo_chown = invfo_chown, 133 .fo_sendfile = invfo_sendfile, 134 .fo_fill_kinfo = kqueue_fill_kinfo, 135 }; 136 137 static int knote_attach(struct knote *kn, struct kqueue *kq); 138 static void knote_drop(struct knote *kn, struct thread *td); 139 static void knote_enqueue(struct knote *kn); 140 static void knote_dequeue(struct knote *kn); 141 static void knote_init(void); 142 static struct knote *knote_alloc(int waitok); 143 static void knote_free(struct knote *kn); 144 145 static void filt_kqdetach(struct knote *kn); 146 static int filt_kqueue(struct knote *kn, long hint); 147 static int filt_procattach(struct knote *kn); 148 static void filt_procdetach(struct knote *kn); 149 static int filt_proc(struct knote *kn, long hint); 150 static int filt_fileattach(struct knote *kn); 151 static void filt_timerexpire(void *knx); 152 static int filt_timerattach(struct knote *kn); 153 static void filt_timerdetach(struct knote *kn); 154 static int filt_timer(struct knote *kn, long hint); 155 static int filt_userattach(struct knote *kn); 156 static void filt_userdetach(struct knote *kn); 157 static int filt_user(struct knote *kn, long hint); 158 static void filt_usertouch(struct knote *kn, struct kevent *kev, 159 u_long type); 160 161 static struct filterops file_filtops = { 162 .f_isfd = 1, 163 .f_attach = filt_fileattach, 164 }; 165 static struct filterops kqread_filtops = { 166 .f_isfd = 1, 167 .f_detach = filt_kqdetach, 168 .f_event = filt_kqueue, 169 }; 170 /* XXX - move to kern_proc.c? */ 171 static struct filterops proc_filtops = { 172 .f_isfd = 0, 173 .f_attach = filt_procattach, 174 .f_detach = filt_procdetach, 175 .f_event = filt_proc, 176 }; 177 static struct filterops timer_filtops = { 178 .f_isfd = 0, 179 .f_attach = filt_timerattach, 180 .f_detach = filt_timerdetach, 181 .f_event = filt_timer, 182 }; 183 static struct filterops user_filtops = { 184 .f_attach = filt_userattach, 185 .f_detach = filt_userdetach, 186 .f_event = filt_user, 187 .f_touch = filt_usertouch, 188 }; 189 190 static uma_zone_t knote_zone; 191 static unsigned int kq_ncallouts = 0; 192 static unsigned int kq_calloutmax = 4 * 1024; 193 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 194 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 195 196 /* XXX - ensure not KN_INFLUX?? */ 197 #define KNOTE_ACTIVATE(kn, islock) do { \ 198 if ((islock)) \ 199 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 200 else \ 201 KQ_LOCK((kn)->kn_kq); \ 202 (kn)->kn_status |= KN_ACTIVE; \ 203 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 204 knote_enqueue((kn)); \ 205 if (!(islock)) \ 206 KQ_UNLOCK((kn)->kn_kq); \ 207 } while(0) 208 #define KQ_LOCK(kq) do { \ 209 mtx_lock(&(kq)->kq_lock); \ 210 } while (0) 211 #define KQ_FLUX_WAKEUP(kq) do { \ 212 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 213 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 214 wakeup((kq)); \ 215 } \ 216 } while (0) 217 #define KQ_UNLOCK_FLUX(kq) do { \ 218 KQ_FLUX_WAKEUP(kq); \ 219 mtx_unlock(&(kq)->kq_lock); \ 220 } while (0) 221 #define KQ_UNLOCK(kq) do { \ 222 mtx_unlock(&(kq)->kq_lock); \ 223 } while (0) 224 #define KQ_OWNED(kq) do { \ 225 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 226 } while (0) 227 #define KQ_NOTOWNED(kq) do { \ 228 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 229 } while (0) 230 231 static struct knlist * 232 kn_list_lock(struct knote *kn) 233 { 234 struct knlist *knl; 235 236 knl = kn->kn_knlist; 237 if (knl != NULL) 238 knl->kl_lock(knl->kl_lockarg); 239 return (knl); 240 } 241 242 static void 243 kn_list_unlock(struct knlist *knl) 244 { 245 bool do_free; 246 247 if (knl == NULL) 248 return; 249 do_free = knl->kl_autodestroy && knlist_empty(knl); 250 knl->kl_unlock(knl->kl_lockarg); 251 if (do_free) { 252 knlist_destroy(knl); 253 free(knl, M_KQUEUE); 254 } 255 } 256 257 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 258 if (islocked) \ 259 KNL_ASSERT_LOCKED(knl); \ 260 else \ 261 KNL_ASSERT_UNLOCKED(knl); \ 262 } while (0) 263 #ifdef INVARIANTS 264 #define KNL_ASSERT_LOCKED(knl) do { \ 265 knl->kl_assert_locked((knl)->kl_lockarg); \ 266 } while (0) 267 #define KNL_ASSERT_UNLOCKED(knl) do { \ 268 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 269 } while (0) 270 #else /* !INVARIANTS */ 271 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 272 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 273 #endif /* INVARIANTS */ 274 275 #ifndef KN_HASHSIZE 276 #define KN_HASHSIZE 64 /* XXX should be tunable */ 277 #endif 278 279 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 280 281 static int 282 filt_nullattach(struct knote *kn) 283 { 284 285 return (ENXIO); 286 }; 287 288 struct filterops null_filtops = { 289 .f_isfd = 0, 290 .f_attach = filt_nullattach, 291 }; 292 293 /* XXX - make SYSINIT to add these, and move into respective modules. */ 294 extern struct filterops sig_filtops; 295 extern struct filterops fs_filtops; 296 297 /* 298 * Table for for all system-defined filters. 299 */ 300 static struct mtx filterops_lock; 301 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 302 MTX_DEF); 303 static struct { 304 struct filterops *for_fop; 305 int for_nolock; 306 int for_refcnt; 307 } sysfilt_ops[EVFILT_SYSCOUNT] = { 308 { &file_filtops, 1 }, /* EVFILT_READ */ 309 { &file_filtops, 1 }, /* EVFILT_WRITE */ 310 { &null_filtops }, /* EVFILT_AIO */ 311 { &file_filtops, 1 }, /* EVFILT_VNODE */ 312 { &proc_filtops, 1 }, /* EVFILT_PROC */ 313 { &sig_filtops, 1 }, /* EVFILT_SIGNAL */ 314 { &timer_filtops, 1 }, /* EVFILT_TIMER */ 315 { &file_filtops, 1 }, /* EVFILT_PROCDESC */ 316 { &fs_filtops, 1 }, /* EVFILT_FS */ 317 { &null_filtops }, /* EVFILT_LIO */ 318 { &user_filtops, 1 }, /* EVFILT_USER */ 319 { &null_filtops }, /* EVFILT_SENDFILE */ 320 }; 321 322 /* 323 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 324 * method. 325 */ 326 static int 327 filt_fileattach(struct knote *kn) 328 { 329 330 return (fo_kqfilter(kn->kn_fp, kn)); 331 } 332 333 /*ARGSUSED*/ 334 static int 335 kqueue_kqfilter(struct file *fp, struct knote *kn) 336 { 337 struct kqueue *kq = kn->kn_fp->f_data; 338 339 if (kn->kn_filter != EVFILT_READ) 340 return (EINVAL); 341 342 kn->kn_status |= KN_KQUEUE; 343 kn->kn_fop = &kqread_filtops; 344 knlist_add(&kq->kq_sel.si_note, kn, 0); 345 346 return (0); 347 } 348 349 static void 350 filt_kqdetach(struct knote *kn) 351 { 352 struct kqueue *kq = kn->kn_fp->f_data; 353 354 knlist_remove(&kq->kq_sel.si_note, kn, 0); 355 } 356 357 /*ARGSUSED*/ 358 static int 359 filt_kqueue(struct knote *kn, long hint) 360 { 361 struct kqueue *kq = kn->kn_fp->f_data; 362 363 kn->kn_data = kq->kq_count; 364 return (kn->kn_data > 0); 365 } 366 367 /* XXX - move to kern_proc.c? */ 368 static int 369 filt_procattach(struct knote *kn) 370 { 371 struct proc *p; 372 int error; 373 bool exiting, immediate; 374 375 exiting = immediate = false; 376 p = pfind(kn->kn_id); 377 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 378 p = zpfind(kn->kn_id); 379 exiting = true; 380 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 381 exiting = true; 382 } 383 384 if (p == NULL) 385 return (ESRCH); 386 if ((error = p_cansee(curthread, p))) { 387 PROC_UNLOCK(p); 388 return (error); 389 } 390 391 kn->kn_ptr.p_proc = p; 392 kn->kn_flags |= EV_CLEAR; /* automatically set */ 393 394 /* 395 * Internal flag indicating registration done by kernel for the 396 * purposes of getting a NOTE_CHILD notification. 397 */ 398 if (kn->kn_flags & EV_FLAG2) { 399 kn->kn_flags &= ~EV_FLAG2; 400 kn->kn_data = kn->kn_sdata; /* ppid */ 401 kn->kn_fflags = NOTE_CHILD; 402 kn->kn_sfflags &= ~(NOTE_EXIT | NOTE_EXEC | NOTE_FORK); 403 immediate = true; /* Force immediate activation of child note. */ 404 } 405 /* 406 * Internal flag indicating registration done by kernel (for other than 407 * NOTE_CHILD). 408 */ 409 if (kn->kn_flags & EV_FLAG1) { 410 kn->kn_flags &= ~EV_FLAG1; 411 } 412 413 knlist_add(p->p_klist, kn, 1); 414 415 /* 416 * Immediately activate any child notes or, in the case of a zombie 417 * target process, exit notes. The latter is necessary to handle the 418 * case where the target process, e.g. a child, dies before the kevent 419 * is registered. 420 */ 421 if (immediate || (exiting && filt_proc(kn, NOTE_EXIT))) 422 KNOTE_ACTIVATE(kn, 0); 423 424 PROC_UNLOCK(p); 425 426 return (0); 427 } 428 429 /* 430 * The knote may be attached to a different process, which may exit, 431 * leaving nothing for the knote to be attached to. So when the process 432 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 433 * it will be deleted when read out. However, as part of the knote deletion, 434 * this routine is called, so a check is needed to avoid actually performing 435 * a detach, because the original process does not exist any more. 436 */ 437 /* XXX - move to kern_proc.c? */ 438 static void 439 filt_procdetach(struct knote *kn) 440 { 441 442 knlist_remove(kn->kn_knlist, kn, 0); 443 kn->kn_ptr.p_proc = NULL; 444 } 445 446 /* XXX - move to kern_proc.c? */ 447 static int 448 filt_proc(struct knote *kn, long hint) 449 { 450 struct proc *p; 451 u_int event; 452 453 p = kn->kn_ptr.p_proc; 454 if (p == NULL) /* already activated, from attach filter */ 455 return (0); 456 457 /* Mask off extra data. */ 458 event = (u_int)hint & NOTE_PCTRLMASK; 459 460 /* If the user is interested in this event, record it. */ 461 if (kn->kn_sfflags & event) 462 kn->kn_fflags |= event; 463 464 /* Process is gone, so flag the event as finished. */ 465 if (event == NOTE_EXIT) { 466 kn->kn_flags |= EV_EOF | EV_ONESHOT; 467 kn->kn_ptr.p_proc = NULL; 468 if (kn->kn_fflags & NOTE_EXIT) 469 kn->kn_data = KW_EXITCODE(p->p_xexit, p->p_xsig); 470 if (kn->kn_fflags == 0) 471 kn->kn_flags |= EV_DROP; 472 return (1); 473 } 474 475 return (kn->kn_fflags != 0); 476 } 477 478 /* 479 * Called when the process forked. It mostly does the same as the 480 * knote(), activating all knotes registered to be activated when the 481 * process forked. Additionally, for each knote attached to the 482 * parent, check whether user wants to track the new process. If so 483 * attach a new knote to it, and immediately report an event with the 484 * child's pid. 485 */ 486 void 487 knote_fork(struct knlist *list, int pid) 488 { 489 struct kqueue *kq; 490 struct knote *kn; 491 struct kevent kev; 492 int error; 493 494 if (list == NULL) 495 return; 496 list->kl_lock(list->kl_lockarg); 497 498 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 499 kq = kn->kn_kq; 500 KQ_LOCK(kq); 501 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 502 KQ_UNLOCK(kq); 503 continue; 504 } 505 506 /* 507 * The same as knote(), activate the event. 508 */ 509 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 510 kn->kn_status |= KN_HASKQLOCK; 511 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 512 KNOTE_ACTIVATE(kn, 1); 513 kn->kn_status &= ~KN_HASKQLOCK; 514 KQ_UNLOCK(kq); 515 continue; 516 } 517 518 /* 519 * The NOTE_TRACK case. In addition to the activation 520 * of the event, we need to register new events to 521 * track the child. Drop the locks in preparation for 522 * the call to kqueue_register(). 523 */ 524 kn->kn_status |= KN_INFLUX; 525 KQ_UNLOCK(kq); 526 list->kl_unlock(list->kl_lockarg); 527 528 /* 529 * Activate existing knote and register tracking knotes with 530 * new process. 531 * 532 * First register a knote to get just the child notice. This 533 * must be a separate note from a potential NOTE_EXIT 534 * notification since both NOTE_CHILD and NOTE_EXIT are defined 535 * to use the data field (in conflicting ways). 536 */ 537 kev.ident = pid; 538 kev.filter = kn->kn_filter; 539 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | 540 EV_FLAG2; 541 kev.fflags = kn->kn_sfflags; 542 kev.data = kn->kn_id; /* parent */ 543 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 544 error = kqueue_register(kq, &kev, NULL, 0); 545 if (error) 546 kn->kn_fflags |= NOTE_TRACKERR; 547 548 /* 549 * Then register another knote to track other potential events 550 * from the new process. 551 */ 552 kev.ident = pid; 553 kev.filter = kn->kn_filter; 554 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 555 kev.fflags = kn->kn_sfflags; 556 kev.data = kn->kn_id; /* parent */ 557 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 558 error = kqueue_register(kq, &kev, NULL, 0); 559 if (error) 560 kn->kn_fflags |= NOTE_TRACKERR; 561 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 562 KNOTE_ACTIVATE(kn, 0); 563 KQ_LOCK(kq); 564 kn->kn_status &= ~KN_INFLUX; 565 KQ_UNLOCK_FLUX(kq); 566 list->kl_lock(list->kl_lockarg); 567 } 568 list->kl_unlock(list->kl_lockarg); 569 } 570 571 /* 572 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 573 * interval timer support code. 574 */ 575 576 #define NOTE_TIMER_PRECMASK \ 577 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS) 578 579 static sbintime_t 580 timer2sbintime(intptr_t data, int flags) 581 { 582 int64_t secs; 583 584 /* 585 * Macros for converting to the fractional second portion of an 586 * sbintime_t using 64bit multiplication to improve precision. 587 */ 588 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 589 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 590 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 591 switch (flags & NOTE_TIMER_PRECMASK) { 592 case NOTE_SECONDS: 593 #ifdef __LP64__ 594 if (data > (SBT_MAX / SBT_1S)) 595 return (SBT_MAX); 596 #endif 597 return ((sbintime_t)data << 32); 598 case NOTE_MSECONDS: /* FALLTHROUGH */ 599 case 0: 600 if (data >= 1000) { 601 secs = data / 1000; 602 #ifdef __LP64__ 603 if (secs > (SBT_MAX / SBT_1S)) 604 return (SBT_MAX); 605 #endif 606 return (secs << 32 | MS_TO_SBT(data % 1000)); 607 } 608 return (MS_TO_SBT(data)); 609 case NOTE_USECONDS: 610 if (data >= 1000000) { 611 secs = data / 1000000; 612 #ifdef __LP64__ 613 if (secs > (SBT_MAX / SBT_1S)) 614 return (SBT_MAX); 615 #endif 616 return (secs << 32 | US_TO_SBT(data % 1000000)); 617 } 618 return (US_TO_SBT(data)); 619 case NOTE_NSECONDS: 620 if (data >= 1000000000) { 621 secs = data / 1000000000; 622 #ifdef __LP64__ 623 if (secs > (SBT_MAX / SBT_1S)) 624 return (SBT_MAX); 625 #endif 626 return (secs << 32 | US_TO_SBT(data % 1000000000)); 627 } 628 return (NS_TO_SBT(data)); 629 default: 630 break; 631 } 632 return (-1); 633 } 634 635 struct kq_timer_cb_data { 636 struct callout c; 637 sbintime_t next; /* next timer event fires at */ 638 sbintime_t to; /* precalculated timer period */ 639 }; 640 641 static void 642 filt_timerexpire(void *knx) 643 { 644 struct knote *kn; 645 struct kq_timer_cb_data *kc; 646 647 kn = knx; 648 kn->kn_data++; 649 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 650 651 if ((kn->kn_flags & EV_ONESHOT) != 0) 652 return; 653 654 kc = kn->kn_ptr.p_v; 655 kc->next += kc->to; 656 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 657 PCPU_GET(cpuid), C_ABSOLUTE); 658 } 659 660 /* 661 * data contains amount of time to sleep 662 */ 663 static int 664 filt_timerattach(struct knote *kn) 665 { 666 struct kq_timer_cb_data *kc; 667 sbintime_t to; 668 unsigned int ncallouts; 669 670 if (kn->kn_sdata < 0) 671 return (EINVAL); 672 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 673 kn->kn_sdata = 1; 674 /* Only precision unit are supported in flags so far */ 675 if ((kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) != 0) 676 return (EINVAL); 677 678 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 679 if (to < 0) 680 return (EINVAL); 681 682 do { 683 ncallouts = kq_ncallouts; 684 if (ncallouts >= kq_calloutmax) 685 return (ENOMEM); 686 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 687 688 kn->kn_flags |= EV_CLEAR; /* automatically set */ 689 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 690 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 691 callout_init(&kc->c, 1); 692 kc->next = to + sbinuptime(); 693 kc->to = to; 694 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 695 PCPU_GET(cpuid), C_ABSOLUTE); 696 697 return (0); 698 } 699 700 static void 701 filt_timerdetach(struct knote *kn) 702 { 703 struct kq_timer_cb_data *kc; 704 unsigned int old; 705 706 kc = kn->kn_ptr.p_v; 707 callout_drain(&kc->c); 708 free(kc, M_KQUEUE); 709 old = atomic_fetchadd_int(&kq_ncallouts, -1); 710 KASSERT(old > 0, ("Number of callouts cannot become negative")); 711 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 712 } 713 714 static int 715 filt_timer(struct knote *kn, long hint) 716 { 717 718 return (kn->kn_data != 0); 719 } 720 721 static int 722 filt_userattach(struct knote *kn) 723 { 724 725 /* 726 * EVFILT_USER knotes are not attached to anything in the kernel. 727 */ 728 kn->kn_hook = NULL; 729 if (kn->kn_fflags & NOTE_TRIGGER) 730 kn->kn_hookid = 1; 731 else 732 kn->kn_hookid = 0; 733 return (0); 734 } 735 736 static void 737 filt_userdetach(__unused struct knote *kn) 738 { 739 740 /* 741 * EVFILT_USER knotes are not attached to anything in the kernel. 742 */ 743 } 744 745 static int 746 filt_user(struct knote *kn, __unused long hint) 747 { 748 749 return (kn->kn_hookid); 750 } 751 752 static void 753 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 754 { 755 u_int ffctrl; 756 757 switch (type) { 758 case EVENT_REGISTER: 759 if (kev->fflags & NOTE_TRIGGER) 760 kn->kn_hookid = 1; 761 762 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 763 kev->fflags &= NOTE_FFLAGSMASK; 764 switch (ffctrl) { 765 case NOTE_FFNOP: 766 break; 767 768 case NOTE_FFAND: 769 kn->kn_sfflags &= kev->fflags; 770 break; 771 772 case NOTE_FFOR: 773 kn->kn_sfflags |= kev->fflags; 774 break; 775 776 case NOTE_FFCOPY: 777 kn->kn_sfflags = kev->fflags; 778 break; 779 780 default: 781 /* XXX Return error? */ 782 break; 783 } 784 kn->kn_sdata = kev->data; 785 if (kev->flags & EV_CLEAR) { 786 kn->kn_hookid = 0; 787 kn->kn_data = 0; 788 kn->kn_fflags = 0; 789 } 790 break; 791 792 case EVENT_PROCESS: 793 *kev = kn->kn_kevent; 794 kev->fflags = kn->kn_sfflags; 795 kev->data = kn->kn_sdata; 796 if (kn->kn_flags & EV_CLEAR) { 797 kn->kn_hookid = 0; 798 kn->kn_data = 0; 799 kn->kn_fflags = 0; 800 } 801 break; 802 803 default: 804 panic("filt_usertouch() - invalid type (%ld)", type); 805 break; 806 } 807 } 808 809 int 810 sys_kqueue(struct thread *td, struct kqueue_args *uap) 811 { 812 813 return (kern_kqueue(td, 0, NULL)); 814 } 815 816 static void 817 kqueue_init(struct kqueue *kq) 818 { 819 820 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF | MTX_DUPOK); 821 TAILQ_INIT(&kq->kq_head); 822 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 823 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 824 } 825 826 int 827 kern_kqueue(struct thread *td, int flags, struct filecaps *fcaps) 828 { 829 struct filedesc *fdp; 830 struct kqueue *kq; 831 struct file *fp; 832 struct ucred *cred; 833 int fd, error; 834 835 fdp = td->td_proc->p_fd; 836 cred = td->td_ucred; 837 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td, RLIMIT_KQUEUES))) 838 return (ENOMEM); 839 840 error = falloc_caps(td, &fp, &fd, flags, fcaps); 841 if (error != 0) { 842 chgkqcnt(cred->cr_ruidinfo, -1, 0); 843 return (error); 844 } 845 846 /* An extra reference on `fp' has been held for us by falloc(). */ 847 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 848 kqueue_init(kq); 849 kq->kq_fdp = fdp; 850 kq->kq_cred = crhold(cred); 851 852 FILEDESC_XLOCK(fdp); 853 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 854 FILEDESC_XUNLOCK(fdp); 855 856 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 857 fdrop(fp, td); 858 859 td->td_retval[0] = fd; 860 return (0); 861 } 862 863 #ifndef _SYS_SYSPROTO_H_ 864 struct kevent_args { 865 int fd; 866 const struct kevent *changelist; 867 int nchanges; 868 struct kevent *eventlist; 869 int nevents; 870 const struct timespec *timeout; 871 }; 872 #endif 873 int 874 sys_kevent(struct thread *td, struct kevent_args *uap) 875 { 876 struct timespec ts, *tsp; 877 struct kevent_copyops k_ops = { 878 .arg = uap, 879 .k_copyout = kevent_copyout, 880 .k_copyin = kevent_copyin, 881 }; 882 #ifdef KTRACE 883 struct kevent *eventlist = uap->eventlist; 884 #endif 885 int error; 886 887 if (uap->timeout != NULL) { 888 error = copyin(uap->timeout, &ts, sizeof(ts)); 889 if (error) 890 return (error); 891 tsp = &ts; 892 } else 893 tsp = NULL; 894 895 #ifdef KTRACE 896 if (KTRPOINT(td, KTR_STRUCT_ARRAY)) 897 ktrstructarray("kevent", UIO_USERSPACE, uap->changelist, 898 uap->nchanges, sizeof(struct kevent)); 899 #endif 900 901 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 902 &k_ops, tsp); 903 904 #ifdef KTRACE 905 if (error == 0 && KTRPOINT(td, KTR_STRUCT_ARRAY)) 906 ktrstructarray("kevent", UIO_USERSPACE, eventlist, 907 td->td_retval[0], sizeof(struct kevent)); 908 #endif 909 910 return (error); 911 } 912 913 /* 914 * Copy 'count' items into the destination list pointed to by uap->eventlist. 915 */ 916 static int 917 kevent_copyout(void *arg, struct kevent *kevp, int count) 918 { 919 struct kevent_args *uap; 920 int error; 921 922 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 923 uap = (struct kevent_args *)arg; 924 925 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 926 if (error == 0) 927 uap->eventlist += count; 928 return (error); 929 } 930 931 /* 932 * Copy 'count' items from the list pointed to by uap->changelist. 933 */ 934 static int 935 kevent_copyin(void *arg, struct kevent *kevp, int count) 936 { 937 struct kevent_args *uap; 938 int error; 939 940 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 941 uap = (struct kevent_args *)arg; 942 943 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 944 if (error == 0) 945 uap->changelist += count; 946 return (error); 947 } 948 949 int 950 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 951 struct kevent_copyops *k_ops, const struct timespec *timeout) 952 { 953 cap_rights_t rights; 954 struct file *fp; 955 int error; 956 957 cap_rights_init(&rights); 958 if (nchanges > 0) 959 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 960 if (nevents > 0) 961 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 962 error = fget(td, fd, &rights, &fp); 963 if (error != 0) 964 return (error); 965 966 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 967 fdrop(fp, td); 968 969 return (error); 970 } 971 972 static int 973 kqueue_kevent(struct kqueue *kq, struct thread *td, int nchanges, int nevents, 974 struct kevent_copyops *k_ops, const struct timespec *timeout) 975 { 976 struct kevent keva[KQ_NEVENTS]; 977 struct kevent *kevp, *changes; 978 int i, n, nerrors, error; 979 980 nerrors = 0; 981 while (nchanges > 0) { 982 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 983 error = k_ops->k_copyin(k_ops->arg, keva, n); 984 if (error) 985 return (error); 986 changes = keva; 987 for (i = 0; i < n; i++) { 988 kevp = &changes[i]; 989 if (!kevp->filter) 990 continue; 991 kevp->flags &= ~EV_SYSFLAGS; 992 error = kqueue_register(kq, kevp, td, 1); 993 if (error || (kevp->flags & EV_RECEIPT)) { 994 if (nevents == 0) 995 return (error); 996 kevp->flags = EV_ERROR; 997 kevp->data = error; 998 (void)k_ops->k_copyout(k_ops->arg, kevp, 1); 999 nevents--; 1000 nerrors++; 1001 } 1002 } 1003 nchanges -= n; 1004 } 1005 if (nerrors) { 1006 td->td_retval[0] = nerrors; 1007 return (0); 1008 } 1009 1010 return (kqueue_scan(kq, nevents, k_ops, timeout, keva, td)); 1011 } 1012 1013 int 1014 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 1015 struct kevent_copyops *k_ops, const struct timespec *timeout) 1016 { 1017 struct kqueue *kq; 1018 int error; 1019 1020 error = kqueue_acquire(fp, &kq); 1021 if (error != 0) 1022 return (error); 1023 error = kqueue_kevent(kq, td, nchanges, nevents, k_ops, timeout); 1024 kqueue_release(kq, 0); 1025 return (error); 1026 } 1027 1028 /* 1029 * Performs a kevent() call on a temporarily created kqueue. This can be 1030 * used to perform one-shot polling, similar to poll() and select(). 1031 */ 1032 int 1033 kern_kevent_anonymous(struct thread *td, int nevents, 1034 struct kevent_copyops *k_ops) 1035 { 1036 struct kqueue kq = {}; 1037 int error; 1038 1039 kqueue_init(&kq); 1040 kq.kq_refcnt = 1; 1041 error = kqueue_kevent(&kq, td, nevents, nevents, k_ops, NULL); 1042 kqueue_drain(&kq, td); 1043 kqueue_destroy(&kq); 1044 return (error); 1045 } 1046 1047 int 1048 kqueue_add_filteropts(int filt, struct filterops *filtops) 1049 { 1050 int error; 1051 1052 error = 0; 1053 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1054 printf( 1055 "trying to add a filterop that is out of range: %d is beyond %d\n", 1056 ~filt, EVFILT_SYSCOUNT); 1057 return EINVAL; 1058 } 1059 mtx_lock(&filterops_lock); 1060 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1061 sysfilt_ops[~filt].for_fop != NULL) 1062 error = EEXIST; 1063 else { 1064 sysfilt_ops[~filt].for_fop = filtops; 1065 sysfilt_ops[~filt].for_refcnt = 0; 1066 } 1067 mtx_unlock(&filterops_lock); 1068 1069 return (error); 1070 } 1071 1072 int 1073 kqueue_del_filteropts(int filt) 1074 { 1075 int error; 1076 1077 error = 0; 1078 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1079 return EINVAL; 1080 1081 mtx_lock(&filterops_lock); 1082 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1083 sysfilt_ops[~filt].for_fop == NULL) 1084 error = EINVAL; 1085 else if (sysfilt_ops[~filt].for_refcnt != 0) 1086 error = EBUSY; 1087 else { 1088 sysfilt_ops[~filt].for_fop = &null_filtops; 1089 sysfilt_ops[~filt].for_refcnt = 0; 1090 } 1091 mtx_unlock(&filterops_lock); 1092 1093 return error; 1094 } 1095 1096 static struct filterops * 1097 kqueue_fo_find(int filt) 1098 { 1099 1100 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1101 return NULL; 1102 1103 if (sysfilt_ops[~filt].for_nolock) 1104 return sysfilt_ops[~filt].for_fop; 1105 1106 mtx_lock(&filterops_lock); 1107 sysfilt_ops[~filt].for_refcnt++; 1108 if (sysfilt_ops[~filt].for_fop == NULL) 1109 sysfilt_ops[~filt].for_fop = &null_filtops; 1110 mtx_unlock(&filterops_lock); 1111 1112 return sysfilt_ops[~filt].for_fop; 1113 } 1114 1115 static void 1116 kqueue_fo_release(int filt) 1117 { 1118 1119 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1120 return; 1121 1122 if (sysfilt_ops[~filt].for_nolock) 1123 return; 1124 1125 mtx_lock(&filterops_lock); 1126 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1127 ("filter object refcount not valid on release")); 1128 sysfilt_ops[~filt].for_refcnt--; 1129 mtx_unlock(&filterops_lock); 1130 } 1131 1132 /* 1133 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1134 * influence if memory allocation should wait. Make sure it is 0 if you 1135 * hold any mutexes. 1136 */ 1137 static int 1138 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1139 { 1140 struct filterops *fops; 1141 struct file *fp; 1142 struct knote *kn, *tkn; 1143 struct knlist *knl; 1144 cap_rights_t rights; 1145 int error, filt, event; 1146 int haskqglobal, filedesc_unlock; 1147 1148 if ((kev->flags & (EV_ENABLE | EV_DISABLE)) == (EV_ENABLE | EV_DISABLE)) 1149 return (EINVAL); 1150 1151 fp = NULL; 1152 kn = NULL; 1153 knl = NULL; 1154 error = 0; 1155 haskqglobal = 0; 1156 filedesc_unlock = 0; 1157 1158 filt = kev->filter; 1159 fops = kqueue_fo_find(filt); 1160 if (fops == NULL) 1161 return EINVAL; 1162 1163 if (kev->flags & EV_ADD) { 1164 /* 1165 * Prevent waiting with locks. Non-sleepable 1166 * allocation failures are handled in the loop, only 1167 * if the spare knote appears to be actually required. 1168 */ 1169 tkn = knote_alloc(waitok); 1170 } else { 1171 tkn = NULL; 1172 } 1173 1174 findkn: 1175 if (fops->f_isfd) { 1176 KASSERT(td != NULL, ("td is NULL")); 1177 if (kev->ident > INT_MAX) 1178 error = EBADF; 1179 else 1180 error = fget(td, kev->ident, 1181 cap_rights_init(&rights, CAP_EVENT), &fp); 1182 if (error) 1183 goto done; 1184 1185 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1186 kev->ident, 0) != 0) { 1187 /* try again */ 1188 fdrop(fp, td); 1189 fp = NULL; 1190 error = kqueue_expand(kq, fops, kev->ident, waitok); 1191 if (error) 1192 goto done; 1193 goto findkn; 1194 } 1195 1196 if (fp->f_type == DTYPE_KQUEUE) { 1197 /* 1198 * If we add some intelligence about what we are doing, 1199 * we should be able to support events on ourselves. 1200 * We need to know when we are doing this to prevent 1201 * getting both the knlist lock and the kq lock since 1202 * they are the same thing. 1203 */ 1204 if (fp->f_data == kq) { 1205 error = EINVAL; 1206 goto done; 1207 } 1208 1209 /* 1210 * Pre-lock the filedesc before the global 1211 * lock mutex, see the comment in 1212 * kqueue_close(). 1213 */ 1214 FILEDESC_XLOCK(td->td_proc->p_fd); 1215 filedesc_unlock = 1; 1216 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1217 } 1218 1219 KQ_LOCK(kq); 1220 if (kev->ident < kq->kq_knlistsize) { 1221 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1222 if (kev->filter == kn->kn_filter) 1223 break; 1224 } 1225 } else { 1226 if ((kev->flags & EV_ADD) == EV_ADD) 1227 kqueue_expand(kq, fops, kev->ident, waitok); 1228 1229 KQ_LOCK(kq); 1230 1231 /* 1232 * If possible, find an existing knote to use for this kevent. 1233 */ 1234 if (kev->filter == EVFILT_PROC && 1235 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1236 /* This is an internal creation of a process tracking 1237 * note. Don't attempt to coalesce this with an 1238 * existing note. 1239 */ 1240 ; 1241 } else if (kq->kq_knhashmask != 0) { 1242 struct klist *list; 1243 1244 list = &kq->kq_knhash[ 1245 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1246 SLIST_FOREACH(kn, list, kn_link) 1247 if (kev->ident == kn->kn_id && 1248 kev->filter == kn->kn_filter) 1249 break; 1250 } 1251 } 1252 1253 /* knote is in the process of changing, wait for it to stabilize. */ 1254 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1255 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1256 if (filedesc_unlock) { 1257 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1258 filedesc_unlock = 0; 1259 } 1260 kq->kq_state |= KQ_FLUXWAIT; 1261 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1262 if (fp != NULL) { 1263 fdrop(fp, td); 1264 fp = NULL; 1265 } 1266 goto findkn; 1267 } 1268 1269 /* 1270 * kn now contains the matching knote, or NULL if no match 1271 */ 1272 if (kn == NULL) { 1273 if (kev->flags & EV_ADD) { 1274 kn = tkn; 1275 tkn = NULL; 1276 if (kn == NULL) { 1277 KQ_UNLOCK(kq); 1278 error = ENOMEM; 1279 goto done; 1280 } 1281 kn->kn_fp = fp; 1282 kn->kn_kq = kq; 1283 kn->kn_fop = fops; 1284 /* 1285 * apply reference counts to knote structure, and 1286 * do not release it at the end of this routine. 1287 */ 1288 fops = NULL; 1289 fp = NULL; 1290 1291 kn->kn_sfflags = kev->fflags; 1292 kn->kn_sdata = kev->data; 1293 kev->fflags = 0; 1294 kev->data = 0; 1295 kn->kn_kevent = *kev; 1296 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1297 EV_ENABLE | EV_DISABLE | EV_FORCEONESHOT); 1298 kn->kn_status = KN_INFLUX|KN_DETACHED; 1299 if ((kev->flags & EV_DISABLE) != 0) 1300 kn->kn_status |= KN_DISABLED; 1301 1302 error = knote_attach(kn, kq); 1303 KQ_UNLOCK(kq); 1304 if (error != 0) { 1305 tkn = kn; 1306 goto done; 1307 } 1308 1309 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1310 knote_drop(kn, td); 1311 goto done; 1312 } 1313 knl = kn_list_lock(kn); 1314 goto done_ev_add; 1315 } else { 1316 /* No matching knote and the EV_ADD flag is not set. */ 1317 KQ_UNLOCK(kq); 1318 error = ENOENT; 1319 goto done; 1320 } 1321 } 1322 1323 if (kev->flags & EV_DELETE) { 1324 kn->kn_status |= KN_INFLUX; 1325 KQ_UNLOCK(kq); 1326 if (!(kn->kn_status & KN_DETACHED)) 1327 kn->kn_fop->f_detach(kn); 1328 knote_drop(kn, td); 1329 goto done; 1330 } 1331 1332 if (kev->flags & EV_FORCEONESHOT) { 1333 kn->kn_flags |= EV_ONESHOT; 1334 KNOTE_ACTIVATE(kn, 1); 1335 } 1336 1337 if ((kev->flags & EV_ENABLE) != 0) 1338 kn->kn_status &= ~KN_DISABLED; 1339 else if ((kev->flags & EV_DISABLE) != 0) 1340 kn->kn_status |= KN_DISABLED; 1341 1342 /* 1343 * The user may change some filter values after the initial EV_ADD, 1344 * but doing so will not reset any filter which has already been 1345 * triggered. 1346 */ 1347 kn->kn_status |= KN_INFLUX | KN_SCAN; 1348 KQ_UNLOCK(kq); 1349 knl = kn_list_lock(kn); 1350 kn->kn_kevent.udata = kev->udata; 1351 if (!fops->f_isfd && fops->f_touch != NULL) { 1352 fops->f_touch(kn, kev, EVENT_REGISTER); 1353 } else { 1354 kn->kn_sfflags = kev->fflags; 1355 kn->kn_sdata = kev->data; 1356 } 1357 1358 done_ev_add: 1359 /* 1360 * We can get here with kn->kn_knlist == NULL. This can happen when 1361 * the initial attach event decides that the event is "completed" 1362 * already, e.g., filt_procattach() is called on a zombie process. It 1363 * will call filt_proc() which will remove it from the list, and NULL 1364 * kn_knlist. 1365 * 1366 * KN_DISABLED will be stable while the knote is in flux, so the 1367 * unlocked read will not race with an update. 1368 */ 1369 if ((kn->kn_status & KN_DISABLED) == 0) 1370 event = kn->kn_fop->f_event(kn, 0); 1371 else 1372 event = 0; 1373 1374 KQ_LOCK(kq); 1375 if (event) 1376 kn->kn_status |= KN_ACTIVE; 1377 if ((kn->kn_status & (KN_ACTIVE | KN_DISABLED | KN_QUEUED)) == 1378 KN_ACTIVE) 1379 knote_enqueue(kn); 1380 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1381 kn_list_unlock(knl); 1382 KQ_UNLOCK_FLUX(kq); 1383 1384 done: 1385 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1386 if (filedesc_unlock) 1387 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1388 if (fp != NULL) 1389 fdrop(fp, td); 1390 knote_free(tkn); 1391 if (fops != NULL) 1392 kqueue_fo_release(filt); 1393 return (error); 1394 } 1395 1396 static int 1397 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1398 { 1399 int error; 1400 struct kqueue *kq; 1401 1402 error = 0; 1403 1404 kq = fp->f_data; 1405 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1406 return (EBADF); 1407 *kqp = kq; 1408 KQ_LOCK(kq); 1409 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1410 KQ_UNLOCK(kq); 1411 return (EBADF); 1412 } 1413 kq->kq_refcnt++; 1414 KQ_UNLOCK(kq); 1415 1416 return error; 1417 } 1418 1419 static void 1420 kqueue_release(struct kqueue *kq, int locked) 1421 { 1422 if (locked) 1423 KQ_OWNED(kq); 1424 else 1425 KQ_LOCK(kq); 1426 kq->kq_refcnt--; 1427 if (kq->kq_refcnt == 1) 1428 wakeup(&kq->kq_refcnt); 1429 if (!locked) 1430 KQ_UNLOCK(kq); 1431 } 1432 1433 static void 1434 kqueue_schedtask(struct kqueue *kq) 1435 { 1436 1437 KQ_OWNED(kq); 1438 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1439 ("scheduling kqueue task while draining")); 1440 1441 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1442 taskqueue_enqueue(taskqueue_kqueue_ctx, &kq->kq_task); 1443 kq->kq_state |= KQ_TASKSCHED; 1444 } 1445 } 1446 1447 /* 1448 * Expand the kq to make sure we have storage for fops/ident pair. 1449 * 1450 * Return 0 on success (or no work necessary), return errno on failure. 1451 * 1452 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1453 * If kqueue_register is called from a non-fd context, there usually/should 1454 * be no locks held. 1455 */ 1456 static int 1457 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1458 int waitok) 1459 { 1460 struct klist *list, *tmp_knhash, *to_free; 1461 u_long tmp_knhashmask; 1462 int size; 1463 int fd; 1464 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1465 1466 KQ_NOTOWNED(kq); 1467 1468 to_free = NULL; 1469 if (fops->f_isfd) { 1470 fd = ident; 1471 if (kq->kq_knlistsize <= fd) { 1472 size = kq->kq_knlistsize; 1473 while (size <= fd) 1474 size += KQEXTENT; 1475 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1476 if (list == NULL) 1477 return ENOMEM; 1478 KQ_LOCK(kq); 1479 if (kq->kq_knlistsize > fd) { 1480 to_free = list; 1481 list = NULL; 1482 } else { 1483 if (kq->kq_knlist != NULL) { 1484 bcopy(kq->kq_knlist, list, 1485 kq->kq_knlistsize * sizeof(*list)); 1486 to_free = kq->kq_knlist; 1487 kq->kq_knlist = NULL; 1488 } 1489 bzero((caddr_t)list + 1490 kq->kq_knlistsize * sizeof(*list), 1491 (size - kq->kq_knlistsize) * sizeof(*list)); 1492 kq->kq_knlistsize = size; 1493 kq->kq_knlist = list; 1494 } 1495 KQ_UNLOCK(kq); 1496 } 1497 } else { 1498 if (kq->kq_knhashmask == 0) { 1499 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1500 &tmp_knhashmask); 1501 if (tmp_knhash == NULL) 1502 return ENOMEM; 1503 KQ_LOCK(kq); 1504 if (kq->kq_knhashmask == 0) { 1505 kq->kq_knhash = tmp_knhash; 1506 kq->kq_knhashmask = tmp_knhashmask; 1507 } else { 1508 to_free = tmp_knhash; 1509 } 1510 KQ_UNLOCK(kq); 1511 } 1512 } 1513 free(to_free, M_KQUEUE); 1514 1515 KQ_NOTOWNED(kq); 1516 return 0; 1517 } 1518 1519 static void 1520 kqueue_task(void *arg, int pending) 1521 { 1522 struct kqueue *kq; 1523 int haskqglobal; 1524 1525 haskqglobal = 0; 1526 kq = arg; 1527 1528 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1529 KQ_LOCK(kq); 1530 1531 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1532 1533 kq->kq_state &= ~KQ_TASKSCHED; 1534 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1535 wakeup(&kq->kq_state); 1536 } 1537 KQ_UNLOCK(kq); 1538 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1539 } 1540 1541 /* 1542 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1543 * We treat KN_MARKER knotes as if they are INFLUX. 1544 */ 1545 static int 1546 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1547 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1548 { 1549 struct kevent *kevp; 1550 struct knote *kn, *marker; 1551 struct knlist *knl; 1552 sbintime_t asbt, rsbt; 1553 int count, error, haskqglobal, influx, nkev, touch; 1554 1555 count = maxevents; 1556 nkev = 0; 1557 error = 0; 1558 haskqglobal = 0; 1559 1560 if (maxevents == 0) 1561 goto done_nl; 1562 1563 rsbt = 0; 1564 if (tsp != NULL) { 1565 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1566 tsp->tv_nsec >= 1000000000) { 1567 error = EINVAL; 1568 goto done_nl; 1569 } 1570 if (timespecisset(tsp)) { 1571 if (tsp->tv_sec <= INT32_MAX) { 1572 rsbt = tstosbt(*tsp); 1573 if (TIMESEL(&asbt, rsbt)) 1574 asbt += tc_tick_sbt; 1575 if (asbt <= SBT_MAX - rsbt) 1576 asbt += rsbt; 1577 else 1578 asbt = 0; 1579 rsbt >>= tc_precexp; 1580 } else 1581 asbt = 0; 1582 } else 1583 asbt = -1; 1584 } else 1585 asbt = 0; 1586 marker = knote_alloc(1); 1587 marker->kn_status = KN_MARKER; 1588 KQ_LOCK(kq); 1589 1590 retry: 1591 kevp = keva; 1592 if (kq->kq_count == 0) { 1593 if (asbt == -1) { 1594 error = EWOULDBLOCK; 1595 } else { 1596 kq->kq_state |= KQ_SLEEP; 1597 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1598 "kqread", asbt, rsbt, C_ABSOLUTE); 1599 } 1600 if (error == 0) 1601 goto retry; 1602 /* don't restart after signals... */ 1603 if (error == ERESTART) 1604 error = EINTR; 1605 else if (error == EWOULDBLOCK) 1606 error = 0; 1607 goto done; 1608 } 1609 1610 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1611 influx = 0; 1612 while (count) { 1613 KQ_OWNED(kq); 1614 kn = TAILQ_FIRST(&kq->kq_head); 1615 1616 if ((kn->kn_status == KN_MARKER && kn != marker) || 1617 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1618 if (influx) { 1619 influx = 0; 1620 KQ_FLUX_WAKEUP(kq); 1621 } 1622 kq->kq_state |= KQ_FLUXWAIT; 1623 error = msleep(kq, &kq->kq_lock, PSOCK, 1624 "kqflxwt", 0); 1625 continue; 1626 } 1627 1628 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1629 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1630 kn->kn_status &= ~KN_QUEUED; 1631 kq->kq_count--; 1632 continue; 1633 } 1634 if (kn == marker) { 1635 KQ_FLUX_WAKEUP(kq); 1636 if (count == maxevents) 1637 goto retry; 1638 goto done; 1639 } 1640 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1641 ("KN_INFLUX set when not suppose to be")); 1642 1643 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1644 kn->kn_status &= ~KN_QUEUED; 1645 kn->kn_status |= KN_INFLUX; 1646 kq->kq_count--; 1647 KQ_UNLOCK(kq); 1648 /* 1649 * We don't need to lock the list since we've marked 1650 * it _INFLUX. 1651 */ 1652 if (!(kn->kn_status & KN_DETACHED)) 1653 kn->kn_fop->f_detach(kn); 1654 knote_drop(kn, td); 1655 KQ_LOCK(kq); 1656 continue; 1657 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1658 kn->kn_status &= ~KN_QUEUED; 1659 kn->kn_status |= KN_INFLUX; 1660 kq->kq_count--; 1661 KQ_UNLOCK(kq); 1662 /* 1663 * We don't need to lock the list since we've marked 1664 * it _INFLUX. 1665 */ 1666 *kevp = kn->kn_kevent; 1667 if (!(kn->kn_status & KN_DETACHED)) 1668 kn->kn_fop->f_detach(kn); 1669 knote_drop(kn, td); 1670 KQ_LOCK(kq); 1671 kn = NULL; 1672 } else { 1673 kn->kn_status |= KN_INFLUX | KN_SCAN; 1674 KQ_UNLOCK(kq); 1675 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1676 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1677 knl = kn_list_lock(kn); 1678 if (kn->kn_fop->f_event(kn, 0) == 0) { 1679 KQ_LOCK(kq); 1680 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1681 kn->kn_status &= 1682 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1683 KN_SCAN); 1684 kq->kq_count--; 1685 kn_list_unlock(knl); 1686 influx = 1; 1687 continue; 1688 } 1689 touch = (!kn->kn_fop->f_isfd && 1690 kn->kn_fop->f_touch != NULL); 1691 if (touch) 1692 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1693 else 1694 *kevp = kn->kn_kevent; 1695 KQ_LOCK(kq); 1696 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1697 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1698 /* 1699 * Manually clear knotes who weren't 1700 * 'touch'ed. 1701 */ 1702 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1703 kn->kn_data = 0; 1704 kn->kn_fflags = 0; 1705 } 1706 if (kn->kn_flags & EV_DISPATCH) 1707 kn->kn_status |= KN_DISABLED; 1708 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1709 kq->kq_count--; 1710 } else 1711 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1712 1713 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1714 kn_list_unlock(knl); 1715 influx = 1; 1716 } 1717 1718 /* we are returning a copy to the user */ 1719 kevp++; 1720 nkev++; 1721 count--; 1722 1723 if (nkev == KQ_NEVENTS) { 1724 influx = 0; 1725 KQ_UNLOCK_FLUX(kq); 1726 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1727 nkev = 0; 1728 kevp = keva; 1729 KQ_LOCK(kq); 1730 if (error) 1731 break; 1732 } 1733 } 1734 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1735 done: 1736 KQ_OWNED(kq); 1737 KQ_UNLOCK_FLUX(kq); 1738 knote_free(marker); 1739 done_nl: 1740 KQ_NOTOWNED(kq); 1741 if (nkev != 0) 1742 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1743 td->td_retval[0] = maxevents - count; 1744 return (error); 1745 } 1746 1747 /*ARGSUSED*/ 1748 static int 1749 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1750 struct ucred *active_cred, struct thread *td) 1751 { 1752 /* 1753 * Enabling sigio causes two major problems: 1754 * 1) infinite recursion: 1755 * Synopsys: kevent is being used to track signals and have FIOASYNC 1756 * set. On receipt of a signal this will cause a kqueue to recurse 1757 * into itself over and over. Sending the sigio causes the kqueue 1758 * to become ready, which in turn posts sigio again, forever. 1759 * Solution: this can be solved by setting a flag in the kqueue that 1760 * we have a SIGIO in progress. 1761 * 2) locking problems: 1762 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1763 * us above the proc and pgrp locks. 1764 * Solution: Post a signal using an async mechanism, being sure to 1765 * record a generation count in the delivery so that we do not deliver 1766 * a signal to the wrong process. 1767 * 1768 * Note, these two mechanisms are somewhat mutually exclusive! 1769 */ 1770 #if 0 1771 struct kqueue *kq; 1772 1773 kq = fp->f_data; 1774 switch (cmd) { 1775 case FIOASYNC: 1776 if (*(int *)data) { 1777 kq->kq_state |= KQ_ASYNC; 1778 } else { 1779 kq->kq_state &= ~KQ_ASYNC; 1780 } 1781 return (0); 1782 1783 case FIOSETOWN: 1784 return (fsetown(*(int *)data, &kq->kq_sigio)); 1785 1786 case FIOGETOWN: 1787 *(int *)data = fgetown(&kq->kq_sigio); 1788 return (0); 1789 } 1790 #endif 1791 1792 return (ENOTTY); 1793 } 1794 1795 /*ARGSUSED*/ 1796 static int 1797 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1798 struct thread *td) 1799 { 1800 struct kqueue *kq; 1801 int revents = 0; 1802 int error; 1803 1804 if ((error = kqueue_acquire(fp, &kq))) 1805 return POLLERR; 1806 1807 KQ_LOCK(kq); 1808 if (events & (POLLIN | POLLRDNORM)) { 1809 if (kq->kq_count) { 1810 revents |= events & (POLLIN | POLLRDNORM); 1811 } else { 1812 selrecord(td, &kq->kq_sel); 1813 if (SEL_WAITING(&kq->kq_sel)) 1814 kq->kq_state |= KQ_SEL; 1815 } 1816 } 1817 kqueue_release(kq, 1); 1818 KQ_UNLOCK(kq); 1819 return (revents); 1820 } 1821 1822 /*ARGSUSED*/ 1823 static int 1824 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1825 struct thread *td) 1826 { 1827 1828 bzero((void *)st, sizeof *st); 1829 /* 1830 * We no longer return kq_count because the unlocked value is useless. 1831 * If you spent all this time getting the count, why not spend your 1832 * syscall better by calling kevent? 1833 * 1834 * XXX - This is needed for libc_r. 1835 */ 1836 st->st_mode = S_IFIFO; 1837 return (0); 1838 } 1839 1840 static void 1841 kqueue_drain(struct kqueue *kq, struct thread *td) 1842 { 1843 struct knote *kn; 1844 int i; 1845 1846 KQ_LOCK(kq); 1847 1848 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1849 ("kqueue already closing")); 1850 kq->kq_state |= KQ_CLOSING; 1851 if (kq->kq_refcnt > 1) 1852 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1853 1854 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1855 1856 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1857 ("kqueue's knlist not empty")); 1858 1859 for (i = 0; i < kq->kq_knlistsize; i++) { 1860 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1861 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1862 kq->kq_state |= KQ_FLUXWAIT; 1863 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1864 continue; 1865 } 1866 kn->kn_status |= KN_INFLUX; 1867 KQ_UNLOCK(kq); 1868 if (!(kn->kn_status & KN_DETACHED)) 1869 kn->kn_fop->f_detach(kn); 1870 knote_drop(kn, td); 1871 KQ_LOCK(kq); 1872 } 1873 } 1874 if (kq->kq_knhashmask != 0) { 1875 for (i = 0; i <= kq->kq_knhashmask; i++) { 1876 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1877 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1878 kq->kq_state |= KQ_FLUXWAIT; 1879 msleep(kq, &kq->kq_lock, PSOCK, 1880 "kqclo2", 0); 1881 continue; 1882 } 1883 kn->kn_status |= KN_INFLUX; 1884 KQ_UNLOCK(kq); 1885 if (!(kn->kn_status & KN_DETACHED)) 1886 kn->kn_fop->f_detach(kn); 1887 knote_drop(kn, td); 1888 KQ_LOCK(kq); 1889 } 1890 } 1891 } 1892 1893 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1894 kq->kq_state |= KQ_TASKDRAIN; 1895 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1896 } 1897 1898 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1899 selwakeuppri(&kq->kq_sel, PSOCK); 1900 if (!SEL_WAITING(&kq->kq_sel)) 1901 kq->kq_state &= ~KQ_SEL; 1902 } 1903 1904 KQ_UNLOCK(kq); 1905 } 1906 1907 static void 1908 kqueue_destroy(struct kqueue *kq) 1909 { 1910 1911 KASSERT(kq->kq_fdp == NULL, 1912 ("kqueue still attached to a file descriptor")); 1913 seldrain(&kq->kq_sel); 1914 knlist_destroy(&kq->kq_sel.si_note); 1915 mtx_destroy(&kq->kq_lock); 1916 1917 if (kq->kq_knhash != NULL) 1918 free(kq->kq_knhash, M_KQUEUE); 1919 if (kq->kq_knlist != NULL) 1920 free(kq->kq_knlist, M_KQUEUE); 1921 1922 funsetown(&kq->kq_sigio); 1923 } 1924 1925 /*ARGSUSED*/ 1926 static int 1927 kqueue_close(struct file *fp, struct thread *td) 1928 { 1929 struct kqueue *kq = fp->f_data; 1930 struct filedesc *fdp; 1931 int error; 1932 int filedesc_unlock; 1933 1934 if ((error = kqueue_acquire(fp, &kq))) 1935 return error; 1936 kqueue_drain(kq, td); 1937 1938 /* 1939 * We could be called due to the knote_drop() doing fdrop(), 1940 * called from kqueue_register(). In this case the global 1941 * lock is owned, and filedesc sx is locked before, to not 1942 * take the sleepable lock after non-sleepable. 1943 */ 1944 fdp = kq->kq_fdp; 1945 kq->kq_fdp = NULL; 1946 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1947 FILEDESC_XLOCK(fdp); 1948 filedesc_unlock = 1; 1949 } else 1950 filedesc_unlock = 0; 1951 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1952 if (filedesc_unlock) 1953 FILEDESC_XUNLOCK(fdp); 1954 1955 kqueue_destroy(kq); 1956 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1957 crfree(kq->kq_cred); 1958 free(kq, M_KQUEUE); 1959 fp->f_data = NULL; 1960 1961 return (0); 1962 } 1963 1964 static int 1965 kqueue_fill_kinfo(struct file *fp, struct kinfo_file *kif, struct filedesc *fdp) 1966 { 1967 1968 kif->kf_type = KF_TYPE_KQUEUE; 1969 return (0); 1970 } 1971 1972 static void 1973 kqueue_wakeup(struct kqueue *kq) 1974 { 1975 KQ_OWNED(kq); 1976 1977 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1978 kq->kq_state &= ~KQ_SLEEP; 1979 wakeup(kq); 1980 } 1981 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1982 selwakeuppri(&kq->kq_sel, PSOCK); 1983 if (!SEL_WAITING(&kq->kq_sel)) 1984 kq->kq_state &= ~KQ_SEL; 1985 } 1986 if (!knlist_empty(&kq->kq_sel.si_note)) 1987 kqueue_schedtask(kq); 1988 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1989 pgsigio(&kq->kq_sigio, SIGIO, 0); 1990 } 1991 } 1992 1993 /* 1994 * Walk down a list of knotes, activating them if their event has triggered. 1995 * 1996 * There is a possibility to optimize in the case of one kq watching another. 1997 * Instead of scheduling a task to wake it up, you could pass enough state 1998 * down the chain to make up the parent kqueue. Make this code functional 1999 * first. 2000 */ 2001 void 2002 knote(struct knlist *list, long hint, int lockflags) 2003 { 2004 struct kqueue *kq; 2005 struct knote *kn, *tkn; 2006 int error; 2007 bool own_influx; 2008 2009 if (list == NULL) 2010 return; 2011 2012 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 2013 2014 if ((lockflags & KNF_LISTLOCKED) == 0) 2015 list->kl_lock(list->kl_lockarg); 2016 2017 /* 2018 * If we unlock the list lock (and set KN_INFLUX), we can 2019 * eliminate the kqueue scheduling, but this will introduce 2020 * four lock/unlock's for each knote to test. Also, marker 2021 * would be needed to keep iteration position, since filters 2022 * or other threads could remove events. 2023 */ 2024 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 2025 kq = kn->kn_kq; 2026 KQ_LOCK(kq); 2027 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 2028 /* 2029 * Do not process the influx notes, except for 2030 * the influx coming from the kq unlock in the 2031 * kqueue_scan(). In the later case, we do 2032 * not interfere with the scan, since the code 2033 * fragment in kqueue_scan() locks the knlist, 2034 * and cannot proceed until we finished. 2035 */ 2036 KQ_UNLOCK(kq); 2037 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 2038 own_influx = (kn->kn_status & KN_INFLUX) == 0; 2039 if (own_influx) 2040 kn->kn_status |= KN_INFLUX; 2041 KQ_UNLOCK(kq); 2042 error = kn->kn_fop->f_event(kn, hint); 2043 KQ_LOCK(kq); 2044 if (own_influx) 2045 kn->kn_status &= ~KN_INFLUX; 2046 if (error) 2047 KNOTE_ACTIVATE(kn, 1); 2048 KQ_UNLOCK_FLUX(kq); 2049 } else { 2050 kn->kn_status |= KN_HASKQLOCK; 2051 if (kn->kn_fop->f_event(kn, hint)) 2052 KNOTE_ACTIVATE(kn, 1); 2053 kn->kn_status &= ~KN_HASKQLOCK; 2054 KQ_UNLOCK(kq); 2055 } 2056 } 2057 if ((lockflags & KNF_LISTLOCKED) == 0) 2058 list->kl_unlock(list->kl_lockarg); 2059 } 2060 2061 /* 2062 * add a knote to a knlist 2063 */ 2064 void 2065 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2066 { 2067 KNL_ASSERT_LOCK(knl, islocked); 2068 KQ_NOTOWNED(kn->kn_kq); 2069 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 2070 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 2071 if (!islocked) 2072 knl->kl_lock(knl->kl_lockarg); 2073 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2074 if (!islocked) 2075 knl->kl_unlock(knl->kl_lockarg); 2076 KQ_LOCK(kn->kn_kq); 2077 kn->kn_knlist = knl; 2078 kn->kn_status &= ~KN_DETACHED; 2079 KQ_UNLOCK(kn->kn_kq); 2080 } 2081 2082 static void 2083 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, 2084 int kqislocked) 2085 { 2086 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 2087 KNL_ASSERT_LOCK(knl, knlislocked); 2088 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2089 if (!kqislocked) 2090 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 2091 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 2092 if (!knlislocked) 2093 knl->kl_lock(knl->kl_lockarg); 2094 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2095 kn->kn_knlist = NULL; 2096 if (!knlislocked) 2097 kn_list_unlock(knl); 2098 if (!kqislocked) 2099 KQ_LOCK(kn->kn_kq); 2100 kn->kn_status |= KN_DETACHED; 2101 if (!kqislocked) 2102 KQ_UNLOCK(kn->kn_kq); 2103 } 2104 2105 /* 2106 * remove knote from the specified knlist 2107 */ 2108 void 2109 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2110 { 2111 2112 knlist_remove_kq(knl, kn, islocked, 0); 2113 } 2114 2115 int 2116 knlist_empty(struct knlist *knl) 2117 { 2118 2119 KNL_ASSERT_LOCKED(knl); 2120 return (SLIST_EMPTY(&knl->kl_list)); 2121 } 2122 2123 static struct mtx knlist_lock; 2124 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2125 MTX_DEF); 2126 static void knlist_mtx_lock(void *arg); 2127 static void knlist_mtx_unlock(void *arg); 2128 2129 static void 2130 knlist_mtx_lock(void *arg) 2131 { 2132 2133 mtx_lock((struct mtx *)arg); 2134 } 2135 2136 static void 2137 knlist_mtx_unlock(void *arg) 2138 { 2139 2140 mtx_unlock((struct mtx *)arg); 2141 } 2142 2143 static void 2144 knlist_mtx_assert_locked(void *arg) 2145 { 2146 2147 mtx_assert((struct mtx *)arg, MA_OWNED); 2148 } 2149 2150 static void 2151 knlist_mtx_assert_unlocked(void *arg) 2152 { 2153 2154 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2155 } 2156 2157 static void 2158 knlist_rw_rlock(void *arg) 2159 { 2160 2161 rw_rlock((struct rwlock *)arg); 2162 } 2163 2164 static void 2165 knlist_rw_runlock(void *arg) 2166 { 2167 2168 rw_runlock((struct rwlock *)arg); 2169 } 2170 2171 static void 2172 knlist_rw_assert_locked(void *arg) 2173 { 2174 2175 rw_assert((struct rwlock *)arg, RA_LOCKED); 2176 } 2177 2178 static void 2179 knlist_rw_assert_unlocked(void *arg) 2180 { 2181 2182 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2183 } 2184 2185 void 2186 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2187 void (*kl_unlock)(void *), 2188 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2189 { 2190 2191 if (lock == NULL) 2192 knl->kl_lockarg = &knlist_lock; 2193 else 2194 knl->kl_lockarg = lock; 2195 2196 if (kl_lock == NULL) 2197 knl->kl_lock = knlist_mtx_lock; 2198 else 2199 knl->kl_lock = kl_lock; 2200 if (kl_unlock == NULL) 2201 knl->kl_unlock = knlist_mtx_unlock; 2202 else 2203 knl->kl_unlock = kl_unlock; 2204 if (kl_assert_locked == NULL) 2205 knl->kl_assert_locked = knlist_mtx_assert_locked; 2206 else 2207 knl->kl_assert_locked = kl_assert_locked; 2208 if (kl_assert_unlocked == NULL) 2209 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2210 else 2211 knl->kl_assert_unlocked = kl_assert_unlocked; 2212 2213 knl->kl_autodestroy = 0; 2214 SLIST_INIT(&knl->kl_list); 2215 } 2216 2217 void 2218 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2219 { 2220 2221 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2222 } 2223 2224 struct knlist * 2225 knlist_alloc(struct mtx *lock) 2226 { 2227 struct knlist *knl; 2228 2229 knl = malloc(sizeof(struct knlist), M_KQUEUE, M_WAITOK); 2230 knlist_init_mtx(knl, lock); 2231 return (knl); 2232 } 2233 2234 void 2235 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2236 { 2237 2238 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2239 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2240 } 2241 2242 void 2243 knlist_destroy(struct knlist *knl) 2244 { 2245 2246 KASSERT(KNLIST_EMPTY(knl), 2247 ("destroying knlist %p with knotes on it", knl)); 2248 } 2249 2250 void 2251 knlist_detach(struct knlist *knl) 2252 { 2253 2254 KNL_ASSERT_LOCKED(knl); 2255 knl->kl_autodestroy = 1; 2256 if (knlist_empty(knl)) { 2257 knlist_destroy(knl); 2258 free(knl, M_KQUEUE); 2259 } 2260 } 2261 2262 /* 2263 * Even if we are locked, we may need to drop the lock to allow any influx 2264 * knotes time to "settle". 2265 */ 2266 void 2267 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2268 { 2269 struct knote *kn, *kn2; 2270 struct kqueue *kq; 2271 2272 KASSERT(!knl->kl_autodestroy, ("cleardel for autodestroy %p", knl)); 2273 if (islocked) 2274 KNL_ASSERT_LOCKED(knl); 2275 else { 2276 KNL_ASSERT_UNLOCKED(knl); 2277 again: /* need to reacquire lock since we have dropped it */ 2278 knl->kl_lock(knl->kl_lockarg); 2279 } 2280 2281 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2282 kq = kn->kn_kq; 2283 KQ_LOCK(kq); 2284 if ((kn->kn_status & KN_INFLUX)) { 2285 KQ_UNLOCK(kq); 2286 continue; 2287 } 2288 knlist_remove_kq(knl, kn, 1, 1); 2289 if (killkn) { 2290 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2291 KQ_UNLOCK(kq); 2292 knote_drop(kn, td); 2293 } else { 2294 /* Make sure cleared knotes disappear soon */ 2295 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2296 KQ_UNLOCK(kq); 2297 } 2298 kq = NULL; 2299 } 2300 2301 if (!SLIST_EMPTY(&knl->kl_list)) { 2302 /* there are still KN_INFLUX remaining */ 2303 kn = SLIST_FIRST(&knl->kl_list); 2304 kq = kn->kn_kq; 2305 KQ_LOCK(kq); 2306 KASSERT(kn->kn_status & KN_INFLUX, 2307 ("knote removed w/o list lock")); 2308 knl->kl_unlock(knl->kl_lockarg); 2309 kq->kq_state |= KQ_FLUXWAIT; 2310 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2311 kq = NULL; 2312 goto again; 2313 } 2314 2315 if (islocked) 2316 KNL_ASSERT_LOCKED(knl); 2317 else { 2318 knl->kl_unlock(knl->kl_lockarg); 2319 KNL_ASSERT_UNLOCKED(knl); 2320 } 2321 } 2322 2323 /* 2324 * Remove all knotes referencing a specified fd must be called with FILEDESC 2325 * lock. This prevents a race where a new fd comes along and occupies the 2326 * entry and we attach a knote to the fd. 2327 */ 2328 void 2329 knote_fdclose(struct thread *td, int fd) 2330 { 2331 struct filedesc *fdp = td->td_proc->p_fd; 2332 struct kqueue *kq; 2333 struct knote *kn; 2334 int influx; 2335 2336 FILEDESC_XLOCK_ASSERT(fdp); 2337 2338 /* 2339 * We shouldn't have to worry about new kevents appearing on fd 2340 * since filedesc is locked. 2341 */ 2342 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2343 KQ_LOCK(kq); 2344 2345 again: 2346 influx = 0; 2347 while (kq->kq_knlistsize > fd && 2348 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2349 if (kn->kn_status & KN_INFLUX) { 2350 /* someone else might be waiting on our knote */ 2351 if (influx) 2352 wakeup(kq); 2353 kq->kq_state |= KQ_FLUXWAIT; 2354 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2355 goto again; 2356 } 2357 kn->kn_status |= KN_INFLUX; 2358 KQ_UNLOCK(kq); 2359 if (!(kn->kn_status & KN_DETACHED)) 2360 kn->kn_fop->f_detach(kn); 2361 knote_drop(kn, td); 2362 influx = 1; 2363 KQ_LOCK(kq); 2364 } 2365 KQ_UNLOCK_FLUX(kq); 2366 } 2367 } 2368 2369 static int 2370 knote_attach(struct knote *kn, struct kqueue *kq) 2371 { 2372 struct klist *list; 2373 2374 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2375 KQ_OWNED(kq); 2376 2377 if (kn->kn_fop->f_isfd) { 2378 if (kn->kn_id >= kq->kq_knlistsize) 2379 return (ENOMEM); 2380 list = &kq->kq_knlist[kn->kn_id]; 2381 } else { 2382 if (kq->kq_knhash == NULL) 2383 return (ENOMEM); 2384 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2385 } 2386 SLIST_INSERT_HEAD(list, kn, kn_link); 2387 return (0); 2388 } 2389 2390 /* 2391 * knote must already have been detached using the f_detach method. 2392 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2393 * to prevent other removal. 2394 */ 2395 static void 2396 knote_drop(struct knote *kn, struct thread *td) 2397 { 2398 struct kqueue *kq; 2399 struct klist *list; 2400 2401 kq = kn->kn_kq; 2402 2403 KQ_NOTOWNED(kq); 2404 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2405 ("knote_drop called without KN_INFLUX set in kn_status")); 2406 2407 KQ_LOCK(kq); 2408 if (kn->kn_fop->f_isfd) 2409 list = &kq->kq_knlist[kn->kn_id]; 2410 else 2411 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2412 2413 if (!SLIST_EMPTY(list)) 2414 SLIST_REMOVE(list, kn, knote, kn_link); 2415 if (kn->kn_status & KN_QUEUED) 2416 knote_dequeue(kn); 2417 KQ_UNLOCK_FLUX(kq); 2418 2419 if (kn->kn_fop->f_isfd) { 2420 fdrop(kn->kn_fp, td); 2421 kn->kn_fp = NULL; 2422 } 2423 kqueue_fo_release(kn->kn_kevent.filter); 2424 kn->kn_fop = NULL; 2425 knote_free(kn); 2426 } 2427 2428 static void 2429 knote_enqueue(struct knote *kn) 2430 { 2431 struct kqueue *kq = kn->kn_kq; 2432 2433 KQ_OWNED(kn->kn_kq); 2434 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2435 2436 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2437 kn->kn_status |= KN_QUEUED; 2438 kq->kq_count++; 2439 kqueue_wakeup(kq); 2440 } 2441 2442 static void 2443 knote_dequeue(struct knote *kn) 2444 { 2445 struct kqueue *kq = kn->kn_kq; 2446 2447 KQ_OWNED(kn->kn_kq); 2448 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2449 2450 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2451 kn->kn_status &= ~KN_QUEUED; 2452 kq->kq_count--; 2453 } 2454 2455 static void 2456 knote_init(void) 2457 { 2458 2459 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2460 NULL, NULL, UMA_ALIGN_PTR, 0); 2461 } 2462 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2463 2464 static struct knote * 2465 knote_alloc(int waitok) 2466 { 2467 2468 return (uma_zalloc(knote_zone, (waitok ? M_WAITOK : M_NOWAIT) | 2469 M_ZERO)); 2470 } 2471 2472 static void 2473 knote_free(struct knote *kn) 2474 { 2475 2476 uma_zfree(knote_zone, kn); 2477 } 2478 2479 /* 2480 * Register the kev w/ the kq specified by fd. 2481 */ 2482 int 2483 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2484 { 2485 struct kqueue *kq; 2486 struct file *fp; 2487 cap_rights_t rights; 2488 int error; 2489 2490 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2491 if (error != 0) 2492 return (error); 2493 if ((error = kqueue_acquire(fp, &kq)) != 0) 2494 goto noacquire; 2495 2496 error = kqueue_register(kq, kev, td, waitok); 2497 kqueue_release(kq, 0); 2498 2499 noacquire: 2500 fdrop(fp, td); 2501 return (error); 2502 }
Cache object: 668a4826b16eea94f05e7c3c95a744a9
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