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("$FreeBSD$"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/capsicum.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/rwlock.h> 41 #include <sys/proc.h> 42 #include <sys/malloc.h> 43 #include <sys/unistd.h> 44 #include <sys/file.h> 45 #include <sys/filedesc.h> 46 #include <sys/filio.h> 47 #include <sys/fcntl.h> 48 #include <sys/kthread.h> 49 #include <sys/selinfo.h> 50 #include <sys/queue.h> 51 #include <sys/event.h> 52 #include <sys/eventvar.h> 53 #include <sys/poll.h> 54 #include <sys/protosw.h> 55 #include <sys/sigio.h> 56 #include <sys/signalvar.h> 57 #include <sys/socket.h> 58 #include <sys/socketvar.h> 59 #include <sys/stat.h> 60 #include <sys/sysctl.h> 61 #include <sys/sysproto.h> 62 #include <sys/syscallsubr.h> 63 #include <sys/taskqueue.h> 64 #include <sys/uio.h> 65 #ifdef KTRACE 66 #include <sys/ktrace.h> 67 #endif 68 #include <machine/atomic.h> 69 70 #include <vm/uma.h> 71 72 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 73 74 /* 75 * This lock is used if multiple kq locks are required. This possibly 76 * should be made into a per proc lock. 77 */ 78 static struct mtx kq_global; 79 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 80 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 81 if (!haslck) \ 82 mtx_lock(lck); \ 83 haslck = 1; \ 84 } while (0) 85 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 86 if (haslck) \ 87 mtx_unlock(lck); \ 88 haslck = 0; \ 89 } while (0) 90 91 TASKQUEUE_DEFINE_THREAD(kqueue); 92 93 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 94 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 95 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 96 struct thread *td, int waitok); 97 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 98 static void kqueue_release(struct kqueue *kq, int locked); 99 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 100 uintptr_t ident, int waitok); 101 static void kqueue_task(void *arg, int pending); 102 static int kqueue_scan(struct kqueue *kq, int maxevents, 103 struct kevent_copyops *k_ops, 104 const struct timespec *timeout, 105 struct kevent *keva, struct thread *td); 106 static void kqueue_wakeup(struct kqueue *kq); 107 static struct filterops *kqueue_fo_find(int filt); 108 static void kqueue_fo_release(int filt); 109 110 static fo_rdwr_t kqueue_read; 111 static fo_rdwr_t kqueue_write; 112 static fo_truncate_t kqueue_truncate; 113 static fo_ioctl_t kqueue_ioctl; 114 static fo_poll_t kqueue_poll; 115 static fo_kqfilter_t kqueue_kqfilter; 116 static fo_stat_t kqueue_stat; 117 static fo_close_t kqueue_close; 118 119 static struct fileops kqueueops = { 120 .fo_read = kqueue_read, 121 .fo_write = kqueue_write, 122 .fo_truncate = kqueue_truncate, 123 .fo_ioctl = kqueue_ioctl, 124 .fo_poll = kqueue_poll, 125 .fo_kqfilter = kqueue_kqfilter, 126 .fo_stat = kqueue_stat, 127 .fo_close = kqueue_close, 128 .fo_chmod = invfo_chmod, 129 .fo_chown = invfo_chown, 130 .fo_sendfile = invfo_sendfile, 131 }; 132 133 static int knote_attach(struct knote *kn, struct kqueue *kq); 134 static void knote_drop(struct knote *kn, struct thread *td); 135 static void knote_enqueue(struct knote *kn); 136 static void knote_dequeue(struct knote *kn); 137 static void knote_init(void); 138 static struct knote *knote_alloc(int waitok); 139 static void knote_free(struct knote *kn); 140 141 static void filt_kqdetach(struct knote *kn); 142 static int filt_kqueue(struct knote *kn, long hint); 143 static int filt_procattach(struct knote *kn); 144 static void filt_procdetach(struct knote *kn); 145 static int filt_proc(struct knote *kn, long hint); 146 static int filt_fileattach(struct knote *kn); 147 static void filt_timerexpire(void *knx); 148 static int filt_timerattach(struct knote *kn); 149 static void filt_timerdetach(struct knote *kn); 150 static int filt_timer(struct knote *kn, long hint); 151 static int filt_userattach(struct knote *kn); 152 static void filt_userdetach(struct knote *kn); 153 static int filt_user(struct knote *kn, long hint); 154 static void filt_usertouch(struct knote *kn, struct kevent *kev, 155 u_long type); 156 157 static struct filterops file_filtops = { 158 .f_isfd = 1, 159 .f_attach = filt_fileattach, 160 }; 161 static struct filterops kqread_filtops = { 162 .f_isfd = 1, 163 .f_detach = filt_kqdetach, 164 .f_event = filt_kqueue, 165 }; 166 /* XXX - move to kern_proc.c? */ 167 static struct filterops proc_filtops = { 168 .f_isfd = 0, 169 .f_attach = filt_procattach, 170 .f_detach = filt_procdetach, 171 .f_event = filt_proc, 172 }; 173 static struct filterops timer_filtops = { 174 .f_isfd = 0, 175 .f_attach = filt_timerattach, 176 .f_detach = filt_timerdetach, 177 .f_event = filt_timer, 178 }; 179 static struct filterops user_filtops = { 180 .f_attach = filt_userattach, 181 .f_detach = filt_userdetach, 182 .f_event = filt_user, 183 .f_touch = filt_usertouch, 184 }; 185 186 static uma_zone_t knote_zone; 187 static unsigned int kq_ncallouts = 0; 188 static unsigned int kq_calloutmax = 4 * 1024; 189 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 190 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 191 192 /* XXX - ensure not KN_INFLUX?? */ 193 #define KNOTE_ACTIVATE(kn, islock) do { \ 194 if ((islock)) \ 195 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 196 else \ 197 KQ_LOCK((kn)->kn_kq); \ 198 (kn)->kn_status |= KN_ACTIVE; \ 199 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 200 knote_enqueue((kn)); \ 201 if (!(islock)) \ 202 KQ_UNLOCK((kn)->kn_kq); \ 203 } while(0) 204 #define KQ_LOCK(kq) do { \ 205 mtx_lock(&(kq)->kq_lock); \ 206 } while (0) 207 #define KQ_FLUX_WAKEUP(kq) do { \ 208 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 209 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 210 wakeup((kq)); \ 211 } \ 212 } while (0) 213 #define KQ_UNLOCK_FLUX(kq) do { \ 214 KQ_FLUX_WAKEUP(kq); \ 215 mtx_unlock(&(kq)->kq_lock); \ 216 } while (0) 217 #define KQ_UNLOCK(kq) do { \ 218 mtx_unlock(&(kq)->kq_lock); \ 219 } while (0) 220 #define KQ_OWNED(kq) do { \ 221 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 222 } while (0) 223 #define KQ_NOTOWNED(kq) do { \ 224 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 225 } while (0) 226 #define KN_LIST_LOCK(kn) do { \ 227 if (kn->kn_knlist != NULL) \ 228 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 229 } while (0) 230 #define KN_LIST_UNLOCK(kn) do { \ 231 if (kn->kn_knlist != NULL) \ 232 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 233 } while (0) 234 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 235 if (islocked) \ 236 KNL_ASSERT_LOCKED(knl); \ 237 else \ 238 KNL_ASSERT_UNLOCKED(knl); \ 239 } while (0) 240 #ifdef INVARIANTS 241 #define KNL_ASSERT_LOCKED(knl) do { \ 242 knl->kl_assert_locked((knl)->kl_lockarg); \ 243 } while (0) 244 #define KNL_ASSERT_UNLOCKED(knl) do { \ 245 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 246 } while (0) 247 #else /* !INVARIANTS */ 248 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 249 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 250 #endif /* INVARIANTS */ 251 252 #define KN_HASHSIZE 64 /* XXX should be tunable */ 253 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 254 255 static int 256 filt_nullattach(struct knote *kn) 257 { 258 259 return (ENXIO); 260 }; 261 262 struct filterops null_filtops = { 263 .f_isfd = 0, 264 .f_attach = filt_nullattach, 265 }; 266 267 /* XXX - make SYSINIT to add these, and move into respective modules. */ 268 extern struct filterops sig_filtops; 269 extern struct filterops fs_filtops; 270 271 /* 272 * Table for for all system-defined filters. 273 */ 274 static struct mtx filterops_lock; 275 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 276 MTX_DEF); 277 static struct { 278 struct filterops *for_fop; 279 int for_refcnt; 280 } sysfilt_ops[EVFILT_SYSCOUNT] = { 281 { &file_filtops }, /* EVFILT_READ */ 282 { &file_filtops }, /* EVFILT_WRITE */ 283 { &null_filtops }, /* EVFILT_AIO */ 284 { &file_filtops }, /* EVFILT_VNODE */ 285 { &proc_filtops }, /* EVFILT_PROC */ 286 { &sig_filtops }, /* EVFILT_SIGNAL */ 287 { &timer_filtops }, /* EVFILT_TIMER */ 288 { &null_filtops }, /* former EVFILT_NETDEV */ 289 { &fs_filtops }, /* EVFILT_FS */ 290 { &null_filtops }, /* EVFILT_LIO */ 291 { &user_filtops }, /* EVFILT_USER */ 292 }; 293 294 /* 295 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 296 * method. 297 */ 298 static int 299 filt_fileattach(struct knote *kn) 300 { 301 302 return (fo_kqfilter(kn->kn_fp, kn)); 303 } 304 305 /*ARGSUSED*/ 306 static int 307 kqueue_kqfilter(struct file *fp, struct knote *kn) 308 { 309 struct kqueue *kq = kn->kn_fp->f_data; 310 311 if (kn->kn_filter != EVFILT_READ) 312 return (EINVAL); 313 314 kn->kn_status |= KN_KQUEUE; 315 kn->kn_fop = &kqread_filtops; 316 knlist_add(&kq->kq_sel.si_note, kn, 0); 317 318 return (0); 319 } 320 321 static void 322 filt_kqdetach(struct knote *kn) 323 { 324 struct kqueue *kq = kn->kn_fp->f_data; 325 326 knlist_remove(&kq->kq_sel.si_note, kn, 0); 327 } 328 329 /*ARGSUSED*/ 330 static int 331 filt_kqueue(struct knote *kn, long hint) 332 { 333 struct kqueue *kq = kn->kn_fp->f_data; 334 335 kn->kn_data = kq->kq_count; 336 return (kn->kn_data > 0); 337 } 338 339 /* XXX - move to kern_proc.c? */ 340 static int 341 filt_procattach(struct knote *kn) 342 { 343 struct proc *p; 344 int immediate; 345 int error; 346 347 immediate = 0; 348 p = pfind(kn->kn_id); 349 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 350 p = zpfind(kn->kn_id); 351 immediate = 1; 352 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 353 immediate = 1; 354 } 355 356 if (p == NULL) 357 return (ESRCH); 358 if ((error = p_cansee(curthread, p))) { 359 PROC_UNLOCK(p); 360 return (error); 361 } 362 363 kn->kn_ptr.p_proc = p; 364 kn->kn_flags |= EV_CLEAR; /* automatically set */ 365 366 /* 367 * Internal flag indicating registration done by kernel for the 368 * purposes of getting a NOTE_CHILD notification. 369 */ 370 if (kn->kn_flags & EV_FLAG2) { 371 kn->kn_flags &= ~EV_FLAG2; 372 kn->kn_data = kn->kn_sdata; /* ppid */ 373 kn->kn_fflags = NOTE_CHILD; 374 kn->kn_sfflags &= ~NOTE_EXIT; 375 immediate = 1; /* Force immediate activation of child note. */ 376 } 377 /* 378 * Internal flag indicating registration done by kernel (for other than 379 * NOTE_CHILD). 380 */ 381 if (kn->kn_flags & EV_FLAG1) { 382 kn->kn_flags &= ~EV_FLAG1; 383 } 384 385 if (immediate == 0) 386 knlist_add(&p->p_klist, kn, 1); 387 388 /* 389 * Immediately activate any child notes or, in the case of a zombie 390 * target process, exit notes. The latter is necessary to handle the 391 * case where the target process, e.g. a child, dies before the kevent 392 * is registered. 393 */ 394 if (immediate && filt_proc(kn, NOTE_EXIT)) 395 KNOTE_ACTIVATE(kn, 0); 396 397 PROC_UNLOCK(p); 398 399 return (0); 400 } 401 402 /* 403 * The knote may be attached to a different process, which may exit, 404 * leaving nothing for the knote to be attached to. So when the process 405 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 406 * it will be deleted when read out. However, as part of the knote deletion, 407 * this routine is called, so a check is needed to avoid actually performing 408 * a detach, because the original process does not exist any more. 409 */ 410 /* XXX - move to kern_proc.c? */ 411 static void 412 filt_procdetach(struct knote *kn) 413 { 414 struct proc *p; 415 416 p = kn->kn_ptr.p_proc; 417 knlist_remove(&p->p_klist, kn, 0); 418 kn->kn_ptr.p_proc = NULL; 419 } 420 421 /* XXX - move to kern_proc.c? */ 422 static int 423 filt_proc(struct knote *kn, long hint) 424 { 425 struct proc *p = kn->kn_ptr.p_proc; 426 u_int event; 427 428 /* 429 * mask off extra data 430 */ 431 event = (u_int)hint & NOTE_PCTRLMASK; 432 433 /* 434 * if the user is interested in this event, record it. 435 */ 436 if (kn->kn_sfflags & event) 437 kn->kn_fflags |= event; 438 439 /* 440 * process is gone, so flag the event as finished. 441 */ 442 if (event == NOTE_EXIT) { 443 if (!(kn->kn_status & KN_DETACHED)) 444 knlist_remove_inevent(&p->p_klist, kn); 445 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 446 kn->kn_ptr.p_proc = NULL; 447 if (kn->kn_fflags & NOTE_EXIT) 448 kn->kn_data = p->p_xstat; 449 if (kn->kn_fflags == 0) 450 kn->kn_flags |= EV_DROP; 451 return (1); 452 } 453 454 return (kn->kn_fflags != 0); 455 } 456 457 /* 458 * Called when the process forked. It mostly does the same as the 459 * knote(), activating all knotes registered to be activated when the 460 * process forked. Additionally, for each knote attached to the 461 * parent, check whether user wants to track the new process. If so 462 * attach a new knote to it, and immediately report an event with the 463 * child's pid. 464 */ 465 void 466 knote_fork(struct knlist *list, int pid) 467 { 468 struct kqueue *kq; 469 struct knote *kn; 470 struct kevent kev; 471 int error; 472 473 if (list == NULL) 474 return; 475 list->kl_lock(list->kl_lockarg); 476 477 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 478 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 479 continue; 480 kq = kn->kn_kq; 481 KQ_LOCK(kq); 482 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 483 KQ_UNLOCK(kq); 484 continue; 485 } 486 487 /* 488 * The same as knote(), activate the event. 489 */ 490 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 491 kn->kn_status |= KN_HASKQLOCK; 492 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 493 KNOTE_ACTIVATE(kn, 1); 494 kn->kn_status &= ~KN_HASKQLOCK; 495 KQ_UNLOCK(kq); 496 continue; 497 } 498 499 /* 500 * The NOTE_TRACK case. In addition to the activation 501 * of the event, we need to register new events to 502 * track the child. Drop the locks in preparation for 503 * the call to kqueue_register(). 504 */ 505 kn->kn_status |= KN_INFLUX; 506 KQ_UNLOCK(kq); 507 list->kl_unlock(list->kl_lockarg); 508 509 /* 510 * Activate existing knote and register tracking knotes with 511 * new process. 512 * 513 * First register a knote to get just the child notice. This 514 * must be a separate note from a potential NOTE_EXIT 515 * notification since both NOTE_CHILD and NOTE_EXIT are defined 516 * to use the data field (in conflicting ways). 517 */ 518 kev.ident = pid; 519 kev.filter = kn->kn_filter; 520 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_ONESHOT | EV_FLAG2; 521 kev.fflags = kn->kn_sfflags; 522 kev.data = kn->kn_id; /* parent */ 523 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 524 error = kqueue_register(kq, &kev, NULL, 0); 525 if (error) 526 kn->kn_fflags |= NOTE_TRACKERR; 527 528 /* 529 * Then register another knote to track other potential events 530 * from the new process. 531 */ 532 kev.ident = pid; 533 kev.filter = kn->kn_filter; 534 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 535 kev.fflags = kn->kn_sfflags; 536 kev.data = kn->kn_id; /* parent */ 537 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 538 error = kqueue_register(kq, &kev, NULL, 0); 539 if (error) 540 kn->kn_fflags |= NOTE_TRACKERR; 541 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 542 KNOTE_ACTIVATE(kn, 0); 543 KQ_LOCK(kq); 544 kn->kn_status &= ~KN_INFLUX; 545 KQ_UNLOCK_FLUX(kq); 546 list->kl_lock(list->kl_lockarg); 547 } 548 list->kl_unlock(list->kl_lockarg); 549 } 550 551 /* 552 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 553 * interval timer support code. 554 */ 555 556 #define NOTE_TIMER_PRECMASK \ 557 (NOTE_SECONDS | NOTE_MSECONDS | NOTE_USECONDS | NOTE_NSECONDS) 558 559 static sbintime_t 560 timer2sbintime(intptr_t data, int flags) 561 { 562 int64_t secs; 563 564 /* 565 * Macros for converting to the fractional second portion of an 566 * sbintime_t using 64bit multiplication to improve precision. 567 */ 568 #define NS_TO_SBT(ns) (((ns) * (((uint64_t)1 << 63) / 500000000)) >> 32) 569 #define US_TO_SBT(us) (((us) * (((uint64_t)1 << 63) / 500000)) >> 32) 570 #define MS_TO_SBT(ms) (((ms) * (((uint64_t)1 << 63) / 500)) >> 32) 571 switch (flags & NOTE_TIMER_PRECMASK) { 572 case NOTE_SECONDS: 573 #ifdef __LP64__ 574 if (data > (SBT_MAX / SBT_1S)) 575 return (SBT_MAX); 576 #endif 577 return ((sbintime_t)data << 32); 578 case NOTE_MSECONDS: /* FALLTHROUGH */ 579 case 0: 580 if (data >= 1000) { 581 secs = data / 1000; 582 #ifdef __LP64__ 583 if (secs > (SBT_MAX / SBT_1S)) 584 return (SBT_MAX); 585 #endif 586 return (secs << 32 | MS_TO_SBT(data % 1000)); 587 } 588 return (MS_TO_SBT(data)); 589 case NOTE_USECONDS: 590 if (data >= 1000000) { 591 secs = data / 1000000; 592 #ifdef __LP64__ 593 if (secs > (SBT_MAX / SBT_1S)) 594 return (SBT_MAX); 595 #endif 596 return (secs << 32 | US_TO_SBT(data % 1000000)); 597 } 598 return (US_TO_SBT(data)); 599 case NOTE_NSECONDS: 600 if (data >= 1000000000) { 601 secs = data / 1000000000; 602 #ifdef __LP64__ 603 if (secs > (SBT_MAX / SBT_1S)) 604 return (SBT_MAX); 605 #endif 606 return (secs << 32 | US_TO_SBT(data % 1000000000)); 607 } 608 return (NS_TO_SBT(data)); 609 default: 610 break; 611 } 612 return (-1); 613 } 614 615 struct kq_timer_cb_data { 616 struct callout c; 617 sbintime_t next; /* next timer event fires at */ 618 sbintime_t to; /* precalculated timer period */ 619 }; 620 621 static void 622 filt_timerexpire(void *knx) 623 { 624 struct knote *kn; 625 struct kq_timer_cb_data *kc; 626 627 kn = knx; 628 kn->kn_data++; 629 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 630 631 if ((kn->kn_flags & EV_ONESHOT) != 0) 632 return; 633 634 kc = kn->kn_ptr.p_v; 635 kc->next += kc->to; 636 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 637 PCPU_GET(cpuid), C_ABSOLUTE); 638 } 639 640 /* 641 * data contains amount of time to sleep 642 */ 643 static int 644 filt_timerattach(struct knote *kn) 645 { 646 struct kq_timer_cb_data *kc; 647 sbintime_t to; 648 unsigned int ncallouts; 649 650 if (kn->kn_sdata < 0) 651 return (EINVAL); 652 if (kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 653 kn->kn_sdata = 1; 654 /* Only precision unit are supported in flags so far */ 655 if ((kn->kn_sfflags & ~NOTE_TIMER_PRECMASK) != 0) 656 return (EINVAL); 657 658 to = timer2sbintime(kn->kn_sdata, kn->kn_sfflags); 659 if (to < 0) 660 return (EINVAL); 661 662 do { 663 ncallouts = kq_ncallouts; 664 if (ncallouts >= kq_calloutmax) 665 return (ENOMEM); 666 } while (!atomic_cmpset_int(&kq_ncallouts, ncallouts, ncallouts + 1)); 667 668 kn->kn_flags |= EV_CLEAR; /* automatically set */ 669 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 670 kn->kn_ptr.p_v = kc = malloc(sizeof(*kc), M_KQUEUE, M_WAITOK); 671 callout_init(&kc->c, 1); 672 kc->next = to + sbinuptime(); 673 kc->to = to; 674 callout_reset_sbt_on(&kc->c, kc->next, 0, filt_timerexpire, kn, 675 PCPU_GET(cpuid), C_ABSOLUTE); 676 677 return (0); 678 } 679 680 static void 681 filt_timerdetach(struct knote *kn) 682 { 683 struct kq_timer_cb_data *kc; 684 unsigned int old; 685 686 kc = kn->kn_ptr.p_v; 687 callout_drain(&kc->c); 688 free(kc, M_KQUEUE); 689 old = atomic_fetchadd_int(&kq_ncallouts, -1); 690 KASSERT(old > 0, ("Number of callouts cannot become negative")); 691 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 692 } 693 694 static int 695 filt_timer(struct knote *kn, long hint) 696 { 697 698 return (kn->kn_data != 0); 699 } 700 701 static int 702 filt_userattach(struct knote *kn) 703 { 704 705 /* 706 * EVFILT_USER knotes are not attached to anything in the kernel. 707 */ 708 kn->kn_hook = NULL; 709 if (kn->kn_fflags & NOTE_TRIGGER) 710 kn->kn_hookid = 1; 711 else 712 kn->kn_hookid = 0; 713 return (0); 714 } 715 716 static void 717 filt_userdetach(__unused struct knote *kn) 718 { 719 720 /* 721 * EVFILT_USER knotes are not attached to anything in the kernel. 722 */ 723 } 724 725 static int 726 filt_user(struct knote *kn, __unused long hint) 727 { 728 729 return (kn->kn_hookid); 730 } 731 732 static void 733 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 734 { 735 u_int ffctrl; 736 737 switch (type) { 738 case EVENT_REGISTER: 739 if (kev->fflags & NOTE_TRIGGER) 740 kn->kn_hookid = 1; 741 742 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 743 kev->fflags &= NOTE_FFLAGSMASK; 744 switch (ffctrl) { 745 case NOTE_FFNOP: 746 break; 747 748 case NOTE_FFAND: 749 kn->kn_sfflags &= kev->fflags; 750 break; 751 752 case NOTE_FFOR: 753 kn->kn_sfflags |= kev->fflags; 754 break; 755 756 case NOTE_FFCOPY: 757 kn->kn_sfflags = kev->fflags; 758 break; 759 760 default: 761 /* XXX Return error? */ 762 break; 763 } 764 kn->kn_sdata = kev->data; 765 if (kev->flags & EV_CLEAR) { 766 kn->kn_hookid = 0; 767 kn->kn_data = 0; 768 kn->kn_fflags = 0; 769 } 770 break; 771 772 case EVENT_PROCESS: 773 *kev = kn->kn_kevent; 774 kev->fflags = kn->kn_sfflags; 775 kev->data = kn->kn_sdata; 776 if (kn->kn_flags & EV_CLEAR) { 777 kn->kn_hookid = 0; 778 kn->kn_data = 0; 779 kn->kn_fflags = 0; 780 } 781 break; 782 783 default: 784 panic("filt_usertouch() - invalid type (%ld)", type); 785 break; 786 } 787 } 788 789 int 790 sys_kqueue(struct thread *td, struct kqueue_args *uap) 791 { 792 793 return (kern_kqueue(td, 0)); 794 } 795 796 int 797 kern_kqueue(struct thread *td, int flags) 798 { 799 struct filedesc *fdp; 800 struct kqueue *kq; 801 struct file *fp; 802 int fd, error; 803 804 fdp = td->td_proc->p_fd; 805 error = falloc(td, &fp, &fd, flags); 806 if (error) 807 goto done2; 808 809 /* An extra reference on `fp' has been held for us by falloc(). */ 810 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 811 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 812 TAILQ_INIT(&kq->kq_head); 813 kq->kq_fdp = fdp; 814 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 815 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 816 817 FILEDESC_XLOCK(fdp); 818 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 819 FILEDESC_XUNLOCK(fdp); 820 821 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 822 fdrop(fp, td); 823 824 td->td_retval[0] = fd; 825 done2: 826 return (error); 827 } 828 829 #ifdef KTRACE 830 static size_t 831 kev_iovlen(int n, u_int kgio) 832 { 833 834 if (n < 0 || n >= kgio / sizeof(struct kevent)) 835 return (kgio); 836 return (n * sizeof(struct kevent)); 837 } 838 #endif 839 840 #ifndef _SYS_SYSPROTO_H_ 841 struct kevent_args { 842 int fd; 843 const struct kevent *changelist; 844 int nchanges; 845 struct kevent *eventlist; 846 int nevents; 847 const struct timespec *timeout; 848 }; 849 #endif 850 int 851 sys_kevent(struct thread *td, struct kevent_args *uap) 852 { 853 struct timespec ts, *tsp; 854 struct kevent_copyops k_ops = { uap, 855 kevent_copyout, 856 kevent_copyin}; 857 int error; 858 #ifdef KTRACE 859 struct uio ktruio; 860 struct iovec ktriov; 861 struct uio *ktruioin = NULL; 862 struct uio *ktruioout = NULL; 863 u_int kgio; 864 #endif 865 866 if (uap->timeout != NULL) { 867 error = copyin(uap->timeout, &ts, sizeof(ts)); 868 if (error) 869 return (error); 870 tsp = &ts; 871 } else 872 tsp = NULL; 873 874 #ifdef KTRACE 875 if (KTRPOINT(td, KTR_GENIO)) { 876 kgio = ktr_geniosize; 877 ktriov.iov_base = uap->changelist; 878 ktriov.iov_len = kev_iovlen(uap->nchanges, kgio); 879 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 880 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 881 .uio_td = td }; 882 ktruioin = cloneuio(&ktruio); 883 ktriov.iov_base = uap->eventlist; 884 ktriov.iov_len = kev_iovlen(uap->nevents, kgio); 885 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 886 ktruioout = cloneuio(&ktruio); 887 } 888 #endif 889 890 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 891 &k_ops, tsp); 892 893 #ifdef KTRACE 894 if (ktruioin != NULL) { 895 ktruioin->uio_resid = kev_iovlen(uap->nchanges, kgio); 896 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 897 ktruioout->uio_resid = kev_iovlen(td->td_retval[0], kgio); 898 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 899 } 900 #endif 901 902 return (error); 903 } 904 905 /* 906 * Copy 'count' items into the destination list pointed to by uap->eventlist. 907 */ 908 static int 909 kevent_copyout(void *arg, struct kevent *kevp, int count) 910 { 911 struct kevent_args *uap; 912 int error; 913 914 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 915 uap = (struct kevent_args *)arg; 916 917 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 918 if (error == 0) 919 uap->eventlist += count; 920 return (error); 921 } 922 923 /* 924 * Copy 'count' items from the list pointed to by uap->changelist. 925 */ 926 static int 927 kevent_copyin(void *arg, struct kevent *kevp, int count) 928 { 929 struct kevent_args *uap; 930 int error; 931 932 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 933 uap = (struct kevent_args *)arg; 934 935 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 936 if (error == 0) 937 uap->changelist += count; 938 return (error); 939 } 940 941 int 942 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 943 struct kevent_copyops *k_ops, const struct timespec *timeout) 944 { 945 cap_rights_t rights; 946 struct file *fp; 947 int error; 948 949 cap_rights_init(&rights); 950 if (nchanges > 0) 951 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 952 if (nevents > 0) 953 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 954 error = fget(td, fd, &rights, &fp); 955 if (error != 0) 956 return (error); 957 958 error = kern_kevent_fp(td, fp, nchanges, nevents, k_ops, timeout); 959 fdrop(fp, td); 960 961 return (error); 962 } 963 964 int 965 kern_kevent_fp(struct thread *td, struct file *fp, int nchanges, int nevents, 966 struct kevent_copyops *k_ops, const struct timespec *timeout) 967 { 968 struct kevent keva[KQ_NEVENTS]; 969 struct kevent *kevp, *changes; 970 struct kqueue *kq; 971 int i, n, nerrors, error; 972 973 error = kqueue_acquire(fp, &kq); 974 if (error != 0) 975 return (error); 976 977 nerrors = 0; 978 979 while (nchanges > 0) { 980 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 981 error = k_ops->k_copyin(k_ops->arg, keva, n); 982 if (error) 983 goto done; 984 changes = keva; 985 for (i = 0; i < n; i++) { 986 kevp = &changes[i]; 987 if (!kevp->filter) 988 continue; 989 kevp->flags &= ~EV_SYSFLAGS; 990 error = kqueue_register(kq, kevp, td, 1); 991 if (error || (kevp->flags & EV_RECEIPT)) { 992 if (nevents != 0) { 993 kevp->flags = EV_ERROR; 994 kevp->data = error; 995 (void) k_ops->k_copyout(k_ops->arg, 996 kevp, 1); 997 nevents--; 998 nerrors++; 999 } else { 1000 goto done; 1001 } 1002 } 1003 } 1004 nchanges -= n; 1005 } 1006 if (nerrors) { 1007 td->td_retval[0] = nerrors; 1008 error = 0; 1009 goto done; 1010 } 1011 1012 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 1013 done: 1014 kqueue_release(kq, 0); 1015 return (error); 1016 } 1017 1018 int 1019 kqueue_add_filteropts(int filt, struct filterops *filtops) 1020 { 1021 int error; 1022 1023 error = 0; 1024 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 1025 printf( 1026 "trying to add a filterop that is out of range: %d is beyond %d\n", 1027 ~filt, EVFILT_SYSCOUNT); 1028 return EINVAL; 1029 } 1030 mtx_lock(&filterops_lock); 1031 if (sysfilt_ops[~filt].for_fop != &null_filtops && 1032 sysfilt_ops[~filt].for_fop != NULL) 1033 error = EEXIST; 1034 else { 1035 sysfilt_ops[~filt].for_fop = filtops; 1036 sysfilt_ops[~filt].for_refcnt = 0; 1037 } 1038 mtx_unlock(&filterops_lock); 1039 1040 return (error); 1041 } 1042 1043 int 1044 kqueue_del_filteropts(int filt) 1045 { 1046 int error; 1047 1048 error = 0; 1049 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1050 return EINVAL; 1051 1052 mtx_lock(&filterops_lock); 1053 if (sysfilt_ops[~filt].for_fop == &null_filtops || 1054 sysfilt_ops[~filt].for_fop == NULL) 1055 error = EINVAL; 1056 else if (sysfilt_ops[~filt].for_refcnt != 0) 1057 error = EBUSY; 1058 else { 1059 sysfilt_ops[~filt].for_fop = &null_filtops; 1060 sysfilt_ops[~filt].for_refcnt = 0; 1061 } 1062 mtx_unlock(&filterops_lock); 1063 1064 return error; 1065 } 1066 1067 static struct filterops * 1068 kqueue_fo_find(int filt) 1069 { 1070 1071 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1072 return NULL; 1073 1074 mtx_lock(&filterops_lock); 1075 sysfilt_ops[~filt].for_refcnt++; 1076 if (sysfilt_ops[~filt].for_fop == NULL) 1077 sysfilt_ops[~filt].for_fop = &null_filtops; 1078 mtx_unlock(&filterops_lock); 1079 1080 return sysfilt_ops[~filt].for_fop; 1081 } 1082 1083 static void 1084 kqueue_fo_release(int filt) 1085 { 1086 1087 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 1088 return; 1089 1090 mtx_lock(&filterops_lock); 1091 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 1092 ("filter object refcount not valid on release")); 1093 sysfilt_ops[~filt].for_refcnt--; 1094 mtx_unlock(&filterops_lock); 1095 } 1096 1097 /* 1098 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 1099 * influence if memory allocation should wait. Make sure it is 0 if you 1100 * hold any mutexes. 1101 */ 1102 static int 1103 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1104 { 1105 struct filterops *fops; 1106 struct file *fp; 1107 struct knote *kn, *tkn; 1108 cap_rights_t rights; 1109 int error, filt, event; 1110 int haskqglobal, filedesc_unlock; 1111 1112 fp = NULL; 1113 kn = NULL; 1114 error = 0; 1115 haskqglobal = 0; 1116 filedesc_unlock = 0; 1117 1118 filt = kev->filter; 1119 fops = kqueue_fo_find(filt); 1120 if (fops == NULL) 1121 return EINVAL; 1122 1123 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1124 1125 findkn: 1126 if (fops->f_isfd) { 1127 KASSERT(td != NULL, ("td is NULL")); 1128 if (kev->ident > INT_MAX) 1129 error = EBADF; 1130 else 1131 error = fget(td, kev->ident, 1132 cap_rights_init(&rights, CAP_EVENT), &fp); 1133 if (error) 1134 goto done; 1135 1136 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1137 kev->ident, 0) != 0) { 1138 /* try again */ 1139 fdrop(fp, td); 1140 fp = NULL; 1141 error = kqueue_expand(kq, fops, kev->ident, waitok); 1142 if (error) 1143 goto done; 1144 goto findkn; 1145 } 1146 1147 if (fp->f_type == DTYPE_KQUEUE) { 1148 /* 1149 * If we add some intelligence about what we are doing, 1150 * we should be able to support events on ourselves. 1151 * We need to know when we are doing this to prevent 1152 * getting both the knlist lock and the kq lock since 1153 * they are the same thing. 1154 */ 1155 if (fp->f_data == kq) { 1156 error = EINVAL; 1157 goto done; 1158 } 1159 1160 /* 1161 * Pre-lock the filedesc before the global 1162 * lock mutex, see the comment in 1163 * kqueue_close(). 1164 */ 1165 FILEDESC_XLOCK(td->td_proc->p_fd); 1166 filedesc_unlock = 1; 1167 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1168 } 1169 1170 KQ_LOCK(kq); 1171 if (kev->ident < kq->kq_knlistsize) { 1172 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1173 if (kev->filter == kn->kn_filter) 1174 break; 1175 } 1176 } else { 1177 if ((kev->flags & EV_ADD) == EV_ADD) 1178 kqueue_expand(kq, fops, kev->ident, waitok); 1179 1180 KQ_LOCK(kq); 1181 1182 /* 1183 * If possible, find an existing knote to use for this kevent. 1184 */ 1185 if (kev->filter == EVFILT_PROC && 1186 (kev->flags & (EV_FLAG1 | EV_FLAG2)) != 0) { 1187 /* This is an internal creation of a process tracking 1188 * note. Don't attempt to coalesce this with an 1189 * existing note. 1190 */ 1191 ; 1192 } else if (kq->kq_knhashmask != 0) { 1193 struct klist *list; 1194 1195 list = &kq->kq_knhash[ 1196 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1197 SLIST_FOREACH(kn, list, kn_link) 1198 if (kev->ident == kn->kn_id && 1199 kev->filter == kn->kn_filter) 1200 break; 1201 } 1202 } 1203 1204 /* knote is in the process of changing, wait for it to stabilize. */ 1205 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1206 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1207 if (filedesc_unlock) { 1208 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1209 filedesc_unlock = 0; 1210 } 1211 kq->kq_state |= KQ_FLUXWAIT; 1212 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1213 if (fp != NULL) { 1214 fdrop(fp, td); 1215 fp = NULL; 1216 } 1217 goto findkn; 1218 } 1219 1220 /* 1221 * kn now contains the matching knote, or NULL if no match 1222 */ 1223 if (kn == NULL) { 1224 if (kev->flags & EV_ADD) { 1225 kn = tkn; 1226 tkn = NULL; 1227 if (kn == NULL) { 1228 KQ_UNLOCK(kq); 1229 error = ENOMEM; 1230 goto done; 1231 } 1232 kn->kn_fp = fp; 1233 kn->kn_kq = kq; 1234 kn->kn_fop = fops; 1235 /* 1236 * apply reference counts to knote structure, and 1237 * do not release it at the end of this routine. 1238 */ 1239 fops = NULL; 1240 fp = NULL; 1241 1242 kn->kn_sfflags = kev->fflags; 1243 kn->kn_sdata = kev->data; 1244 kev->fflags = 0; 1245 kev->data = 0; 1246 kn->kn_kevent = *kev; 1247 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1248 EV_ENABLE | EV_DISABLE); 1249 kn->kn_status = KN_INFLUX|KN_DETACHED; 1250 1251 error = knote_attach(kn, kq); 1252 KQ_UNLOCK(kq); 1253 if (error != 0) { 1254 tkn = kn; 1255 goto done; 1256 } 1257 1258 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1259 knote_drop(kn, td); 1260 goto done; 1261 } 1262 KN_LIST_LOCK(kn); 1263 goto done_ev_add; 1264 } else { 1265 /* No matching knote and the EV_ADD flag is not set. */ 1266 KQ_UNLOCK(kq); 1267 error = ENOENT; 1268 goto done; 1269 } 1270 } 1271 1272 if (kev->flags & EV_DELETE) { 1273 kn->kn_status |= KN_INFLUX; 1274 KQ_UNLOCK(kq); 1275 if (!(kn->kn_status & KN_DETACHED)) 1276 kn->kn_fop->f_detach(kn); 1277 knote_drop(kn, td); 1278 goto done; 1279 } 1280 1281 /* 1282 * The user may change some filter values after the initial EV_ADD, 1283 * but doing so will not reset any filter which has already been 1284 * triggered. 1285 */ 1286 kn->kn_status |= KN_INFLUX | KN_SCAN; 1287 KQ_UNLOCK(kq); 1288 KN_LIST_LOCK(kn); 1289 kn->kn_kevent.udata = kev->udata; 1290 if (!fops->f_isfd && fops->f_touch != NULL) { 1291 fops->f_touch(kn, kev, EVENT_REGISTER); 1292 } else { 1293 kn->kn_sfflags = kev->fflags; 1294 kn->kn_sdata = kev->data; 1295 } 1296 1297 /* 1298 * We can get here with kn->kn_knlist == NULL. This can happen when 1299 * the initial attach event decides that the event is "completed" 1300 * already. i.e. filt_procattach is called on a zombie process. It 1301 * will call filt_proc which will remove it from the list, and NULL 1302 * kn_knlist. 1303 */ 1304 done_ev_add: 1305 event = kn->kn_fop->f_event(kn, 0); 1306 KQ_LOCK(kq); 1307 if (event) 1308 KNOTE_ACTIVATE(kn, 1); 1309 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1310 KN_LIST_UNLOCK(kn); 1311 1312 if ((kev->flags & EV_DISABLE) && 1313 ((kn->kn_status & KN_DISABLED) == 0)) { 1314 kn->kn_status |= KN_DISABLED; 1315 } 1316 1317 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1318 kn->kn_status &= ~KN_DISABLED; 1319 if ((kn->kn_status & KN_ACTIVE) && 1320 ((kn->kn_status & KN_QUEUED) == 0)) 1321 knote_enqueue(kn); 1322 } 1323 KQ_UNLOCK_FLUX(kq); 1324 1325 done: 1326 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1327 if (filedesc_unlock) 1328 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1329 if (fp != NULL) 1330 fdrop(fp, td); 1331 if (tkn != NULL) 1332 knote_free(tkn); 1333 if (fops != NULL) 1334 kqueue_fo_release(filt); 1335 return (error); 1336 } 1337 1338 static int 1339 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1340 { 1341 int error; 1342 struct kqueue *kq; 1343 1344 error = 0; 1345 1346 kq = fp->f_data; 1347 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1348 return (EBADF); 1349 *kqp = kq; 1350 KQ_LOCK(kq); 1351 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1352 KQ_UNLOCK(kq); 1353 return (EBADF); 1354 } 1355 kq->kq_refcnt++; 1356 KQ_UNLOCK(kq); 1357 1358 return error; 1359 } 1360 1361 static void 1362 kqueue_release(struct kqueue *kq, int locked) 1363 { 1364 if (locked) 1365 KQ_OWNED(kq); 1366 else 1367 KQ_LOCK(kq); 1368 kq->kq_refcnt--; 1369 if (kq->kq_refcnt == 1) 1370 wakeup(&kq->kq_refcnt); 1371 if (!locked) 1372 KQ_UNLOCK(kq); 1373 } 1374 1375 static void 1376 kqueue_schedtask(struct kqueue *kq) 1377 { 1378 1379 KQ_OWNED(kq); 1380 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1381 ("scheduling kqueue task while draining")); 1382 1383 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1384 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1385 kq->kq_state |= KQ_TASKSCHED; 1386 } 1387 } 1388 1389 /* 1390 * Expand the kq to make sure we have storage for fops/ident pair. 1391 * 1392 * Return 0 on success (or no work necessary), return errno on failure. 1393 * 1394 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1395 * If kqueue_register is called from a non-fd context, there usually/should 1396 * be no locks held. 1397 */ 1398 static int 1399 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1400 int waitok) 1401 { 1402 struct klist *list, *tmp_knhash, *to_free; 1403 u_long tmp_knhashmask; 1404 int size; 1405 int fd; 1406 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1407 1408 KQ_NOTOWNED(kq); 1409 1410 to_free = NULL; 1411 if (fops->f_isfd) { 1412 fd = ident; 1413 if (kq->kq_knlistsize <= fd) { 1414 size = kq->kq_knlistsize; 1415 while (size <= fd) 1416 size += KQEXTENT; 1417 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1418 if (list == NULL) 1419 return ENOMEM; 1420 KQ_LOCK(kq); 1421 if (kq->kq_knlistsize > fd) { 1422 to_free = list; 1423 list = NULL; 1424 } else { 1425 if (kq->kq_knlist != NULL) { 1426 bcopy(kq->kq_knlist, list, 1427 kq->kq_knlistsize * sizeof(*list)); 1428 to_free = kq->kq_knlist; 1429 kq->kq_knlist = NULL; 1430 } 1431 bzero((caddr_t)list + 1432 kq->kq_knlistsize * sizeof(*list), 1433 (size - kq->kq_knlistsize) * sizeof(*list)); 1434 kq->kq_knlistsize = size; 1435 kq->kq_knlist = list; 1436 } 1437 KQ_UNLOCK(kq); 1438 } 1439 } else { 1440 if (kq->kq_knhashmask == 0) { 1441 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1442 &tmp_knhashmask); 1443 if (tmp_knhash == NULL) 1444 return ENOMEM; 1445 KQ_LOCK(kq); 1446 if (kq->kq_knhashmask == 0) { 1447 kq->kq_knhash = tmp_knhash; 1448 kq->kq_knhashmask = tmp_knhashmask; 1449 } else { 1450 to_free = tmp_knhash; 1451 } 1452 KQ_UNLOCK(kq); 1453 } 1454 } 1455 free(to_free, M_KQUEUE); 1456 1457 KQ_NOTOWNED(kq); 1458 return 0; 1459 } 1460 1461 static void 1462 kqueue_task(void *arg, int pending) 1463 { 1464 struct kqueue *kq; 1465 int haskqglobal; 1466 1467 haskqglobal = 0; 1468 kq = arg; 1469 1470 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1471 KQ_LOCK(kq); 1472 1473 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1474 1475 kq->kq_state &= ~KQ_TASKSCHED; 1476 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1477 wakeup(&kq->kq_state); 1478 } 1479 KQ_UNLOCK(kq); 1480 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1481 } 1482 1483 /* 1484 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1485 * We treat KN_MARKER knotes as if they are INFLUX. 1486 */ 1487 static int 1488 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1489 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1490 { 1491 struct kevent *kevp; 1492 struct knote *kn, *marker; 1493 sbintime_t asbt, rsbt; 1494 int count, error, haskqglobal, influx, nkev, touch; 1495 1496 count = maxevents; 1497 nkev = 0; 1498 error = 0; 1499 haskqglobal = 0; 1500 1501 if (maxevents == 0) 1502 goto done_nl; 1503 1504 rsbt = 0; 1505 if (tsp != NULL) { 1506 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1507 tsp->tv_nsec >= 1000000000) { 1508 error = EINVAL; 1509 goto done_nl; 1510 } 1511 if (timespecisset(tsp)) { 1512 if (tsp->tv_sec <= INT32_MAX) { 1513 rsbt = tstosbt(*tsp); 1514 if (TIMESEL(&asbt, rsbt)) 1515 asbt += tc_tick_sbt; 1516 if (asbt <= SBT_MAX - rsbt) 1517 asbt += rsbt; 1518 else 1519 asbt = 0; 1520 rsbt >>= tc_precexp; 1521 } else 1522 asbt = 0; 1523 } else 1524 asbt = -1; 1525 } else 1526 asbt = 0; 1527 marker = knote_alloc(1); 1528 if (marker == NULL) { 1529 error = ENOMEM; 1530 goto done_nl; 1531 } 1532 marker->kn_status = KN_MARKER; 1533 KQ_LOCK(kq); 1534 1535 retry: 1536 kevp = keva; 1537 if (kq->kq_count == 0) { 1538 if (asbt == -1) { 1539 error = EWOULDBLOCK; 1540 } else { 1541 kq->kq_state |= KQ_SLEEP; 1542 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1543 "kqread", asbt, rsbt, C_ABSOLUTE); 1544 } 1545 if (error == 0) 1546 goto retry; 1547 /* don't restart after signals... */ 1548 if (error == ERESTART) 1549 error = EINTR; 1550 else if (error == EWOULDBLOCK) 1551 error = 0; 1552 goto done; 1553 } 1554 1555 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1556 influx = 0; 1557 while (count) { 1558 KQ_OWNED(kq); 1559 kn = TAILQ_FIRST(&kq->kq_head); 1560 1561 if ((kn->kn_status == KN_MARKER && kn != marker) || 1562 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1563 if (influx) { 1564 influx = 0; 1565 KQ_FLUX_WAKEUP(kq); 1566 } 1567 kq->kq_state |= KQ_FLUXWAIT; 1568 error = msleep(kq, &kq->kq_lock, PSOCK, 1569 "kqflxwt", 0); 1570 continue; 1571 } 1572 1573 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1574 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1575 kn->kn_status &= ~KN_QUEUED; 1576 kq->kq_count--; 1577 continue; 1578 } 1579 if (kn == marker) { 1580 KQ_FLUX_WAKEUP(kq); 1581 if (count == maxevents) 1582 goto retry; 1583 goto done; 1584 } 1585 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1586 ("KN_INFLUX set when not suppose to be")); 1587 1588 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1589 kn->kn_status &= ~KN_QUEUED; 1590 kn->kn_status |= KN_INFLUX; 1591 kq->kq_count--; 1592 KQ_UNLOCK(kq); 1593 /* 1594 * We don't need to lock the list since we've marked 1595 * it _INFLUX. 1596 */ 1597 if (!(kn->kn_status & KN_DETACHED)) 1598 kn->kn_fop->f_detach(kn); 1599 knote_drop(kn, td); 1600 KQ_LOCK(kq); 1601 continue; 1602 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1603 kn->kn_status &= ~KN_QUEUED; 1604 kn->kn_status |= KN_INFLUX; 1605 kq->kq_count--; 1606 KQ_UNLOCK(kq); 1607 /* 1608 * We don't need to lock the list since we've marked 1609 * it _INFLUX. 1610 */ 1611 *kevp = kn->kn_kevent; 1612 if (!(kn->kn_status & KN_DETACHED)) 1613 kn->kn_fop->f_detach(kn); 1614 knote_drop(kn, td); 1615 KQ_LOCK(kq); 1616 kn = NULL; 1617 } else { 1618 kn->kn_status |= KN_INFLUX | KN_SCAN; 1619 KQ_UNLOCK(kq); 1620 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1621 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1622 KN_LIST_LOCK(kn); 1623 if (kn->kn_fop->f_event(kn, 0) == 0) { 1624 KQ_LOCK(kq); 1625 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1626 kn->kn_status &= 1627 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX | 1628 KN_SCAN); 1629 kq->kq_count--; 1630 KN_LIST_UNLOCK(kn); 1631 influx = 1; 1632 continue; 1633 } 1634 touch = (!kn->kn_fop->f_isfd && 1635 kn->kn_fop->f_touch != NULL); 1636 if (touch) 1637 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1638 else 1639 *kevp = kn->kn_kevent; 1640 KQ_LOCK(kq); 1641 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1642 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1643 /* 1644 * Manually clear knotes who weren't 1645 * 'touch'ed. 1646 */ 1647 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1648 kn->kn_data = 0; 1649 kn->kn_fflags = 0; 1650 } 1651 if (kn->kn_flags & EV_DISPATCH) 1652 kn->kn_status |= KN_DISABLED; 1653 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1654 kq->kq_count--; 1655 } else 1656 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1657 1658 kn->kn_status &= ~(KN_INFLUX | KN_SCAN); 1659 KN_LIST_UNLOCK(kn); 1660 influx = 1; 1661 } 1662 1663 /* we are returning a copy to the user */ 1664 kevp++; 1665 nkev++; 1666 count--; 1667 1668 if (nkev == KQ_NEVENTS) { 1669 influx = 0; 1670 KQ_UNLOCK_FLUX(kq); 1671 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1672 nkev = 0; 1673 kevp = keva; 1674 KQ_LOCK(kq); 1675 if (error) 1676 break; 1677 } 1678 } 1679 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1680 done: 1681 KQ_OWNED(kq); 1682 KQ_UNLOCK_FLUX(kq); 1683 knote_free(marker); 1684 done_nl: 1685 KQ_NOTOWNED(kq); 1686 if (nkev != 0) 1687 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1688 td->td_retval[0] = maxevents - count; 1689 return (error); 1690 } 1691 1692 /* 1693 * XXX 1694 * This could be expanded to call kqueue_scan, if desired. 1695 */ 1696 /*ARGSUSED*/ 1697 static int 1698 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1699 int flags, struct thread *td) 1700 { 1701 return (ENXIO); 1702 } 1703 1704 /*ARGSUSED*/ 1705 static int 1706 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1707 int flags, struct thread *td) 1708 { 1709 return (ENXIO); 1710 } 1711 1712 /*ARGSUSED*/ 1713 static int 1714 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1715 struct thread *td) 1716 { 1717 1718 return (EINVAL); 1719 } 1720 1721 /*ARGSUSED*/ 1722 static int 1723 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1724 struct ucred *active_cred, struct thread *td) 1725 { 1726 /* 1727 * Enabling sigio causes two major problems: 1728 * 1) infinite recursion: 1729 * Synopsys: kevent is being used to track signals and have FIOASYNC 1730 * set. On receipt of a signal this will cause a kqueue to recurse 1731 * into itself over and over. Sending the sigio causes the kqueue 1732 * to become ready, which in turn posts sigio again, forever. 1733 * Solution: this can be solved by setting a flag in the kqueue that 1734 * we have a SIGIO in progress. 1735 * 2) locking problems: 1736 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1737 * us above the proc and pgrp locks. 1738 * Solution: Post a signal using an async mechanism, being sure to 1739 * record a generation count in the delivery so that we do not deliver 1740 * a signal to the wrong process. 1741 * 1742 * Note, these two mechanisms are somewhat mutually exclusive! 1743 */ 1744 #if 0 1745 struct kqueue *kq; 1746 1747 kq = fp->f_data; 1748 switch (cmd) { 1749 case FIOASYNC: 1750 if (*(int *)data) { 1751 kq->kq_state |= KQ_ASYNC; 1752 } else { 1753 kq->kq_state &= ~KQ_ASYNC; 1754 } 1755 return (0); 1756 1757 case FIOSETOWN: 1758 return (fsetown(*(int *)data, &kq->kq_sigio)); 1759 1760 case FIOGETOWN: 1761 *(int *)data = fgetown(&kq->kq_sigio); 1762 return (0); 1763 } 1764 #endif 1765 1766 return (ENOTTY); 1767 } 1768 1769 /*ARGSUSED*/ 1770 static int 1771 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1772 struct thread *td) 1773 { 1774 struct kqueue *kq; 1775 int revents = 0; 1776 int error; 1777 1778 if ((error = kqueue_acquire(fp, &kq))) 1779 return POLLERR; 1780 1781 KQ_LOCK(kq); 1782 if (events & (POLLIN | POLLRDNORM)) { 1783 if (kq->kq_count) { 1784 revents |= events & (POLLIN | POLLRDNORM); 1785 } else { 1786 selrecord(td, &kq->kq_sel); 1787 if (SEL_WAITING(&kq->kq_sel)) 1788 kq->kq_state |= KQ_SEL; 1789 } 1790 } 1791 kqueue_release(kq, 1); 1792 KQ_UNLOCK(kq); 1793 return (revents); 1794 } 1795 1796 /*ARGSUSED*/ 1797 static int 1798 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1799 struct thread *td) 1800 { 1801 1802 bzero((void *)st, sizeof *st); 1803 /* 1804 * We no longer return kq_count because the unlocked value is useless. 1805 * If you spent all this time getting the count, why not spend your 1806 * syscall better by calling kevent? 1807 * 1808 * XXX - This is needed for libc_r. 1809 */ 1810 st->st_mode = S_IFIFO; 1811 return (0); 1812 } 1813 1814 /*ARGSUSED*/ 1815 static int 1816 kqueue_close(struct file *fp, struct thread *td) 1817 { 1818 struct kqueue *kq = fp->f_data; 1819 struct filedesc *fdp; 1820 struct knote *kn; 1821 int i; 1822 int error; 1823 int filedesc_unlock; 1824 1825 if ((error = kqueue_acquire(fp, &kq))) 1826 return error; 1827 1828 filedesc_unlock = 0; 1829 KQ_LOCK(kq); 1830 1831 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1832 ("kqueue already closing")); 1833 kq->kq_state |= KQ_CLOSING; 1834 if (kq->kq_refcnt > 1) 1835 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1836 1837 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1838 fdp = kq->kq_fdp; 1839 1840 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1841 ("kqueue's knlist not empty")); 1842 1843 for (i = 0; i < kq->kq_knlistsize; i++) { 1844 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1845 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1846 kq->kq_state |= KQ_FLUXWAIT; 1847 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1848 continue; 1849 } 1850 kn->kn_status |= KN_INFLUX; 1851 KQ_UNLOCK(kq); 1852 if (!(kn->kn_status & KN_DETACHED)) 1853 kn->kn_fop->f_detach(kn); 1854 knote_drop(kn, td); 1855 KQ_LOCK(kq); 1856 } 1857 } 1858 if (kq->kq_knhashmask != 0) { 1859 for (i = 0; i <= kq->kq_knhashmask; i++) { 1860 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1861 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1862 kq->kq_state |= KQ_FLUXWAIT; 1863 msleep(kq, &kq->kq_lock, PSOCK, 1864 "kqclo2", 0); 1865 continue; 1866 } 1867 kn->kn_status |= KN_INFLUX; 1868 KQ_UNLOCK(kq); 1869 if (!(kn->kn_status & KN_DETACHED)) 1870 kn->kn_fop->f_detach(kn); 1871 knote_drop(kn, td); 1872 KQ_LOCK(kq); 1873 } 1874 } 1875 } 1876 1877 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1878 kq->kq_state |= KQ_TASKDRAIN; 1879 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1880 } 1881 1882 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1883 selwakeuppri(&kq->kq_sel, PSOCK); 1884 if (!SEL_WAITING(&kq->kq_sel)) 1885 kq->kq_state &= ~KQ_SEL; 1886 } 1887 1888 KQ_UNLOCK(kq); 1889 1890 /* 1891 * We could be called due to the knote_drop() doing fdrop(), 1892 * called from kqueue_register(). In this case the global 1893 * lock is owned, and filedesc sx is locked before, to not 1894 * take the sleepable lock after non-sleepable. 1895 */ 1896 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1897 FILEDESC_XLOCK(fdp); 1898 filedesc_unlock = 1; 1899 } else 1900 filedesc_unlock = 0; 1901 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1902 if (filedesc_unlock) 1903 FILEDESC_XUNLOCK(fdp); 1904 1905 seldrain(&kq->kq_sel); 1906 knlist_destroy(&kq->kq_sel.si_note); 1907 mtx_destroy(&kq->kq_lock); 1908 kq->kq_fdp = NULL; 1909 1910 if (kq->kq_knhash != NULL) 1911 free(kq->kq_knhash, M_KQUEUE); 1912 if (kq->kq_knlist != NULL) 1913 free(kq->kq_knlist, M_KQUEUE); 1914 1915 funsetown(&kq->kq_sigio); 1916 free(kq, M_KQUEUE); 1917 fp->f_data = NULL; 1918 1919 return (0); 1920 } 1921 1922 static void 1923 kqueue_wakeup(struct kqueue *kq) 1924 { 1925 KQ_OWNED(kq); 1926 1927 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1928 kq->kq_state &= ~KQ_SLEEP; 1929 wakeup(kq); 1930 } 1931 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1932 selwakeuppri(&kq->kq_sel, PSOCK); 1933 if (!SEL_WAITING(&kq->kq_sel)) 1934 kq->kq_state &= ~KQ_SEL; 1935 } 1936 if (!knlist_empty(&kq->kq_sel.si_note)) 1937 kqueue_schedtask(kq); 1938 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1939 pgsigio(&kq->kq_sigio, SIGIO, 0); 1940 } 1941 } 1942 1943 /* 1944 * Walk down a list of knotes, activating them if their event has triggered. 1945 * 1946 * There is a possibility to optimize in the case of one kq watching another. 1947 * Instead of scheduling a task to wake it up, you could pass enough state 1948 * down the chain to make up the parent kqueue. Make this code functional 1949 * first. 1950 */ 1951 void 1952 knote(struct knlist *list, long hint, int lockflags) 1953 { 1954 struct kqueue *kq; 1955 struct knote *kn, *tkn; 1956 int error; 1957 bool own_influx; 1958 1959 if (list == NULL) 1960 return; 1961 1962 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1963 1964 if ((lockflags & KNF_LISTLOCKED) == 0) 1965 list->kl_lock(list->kl_lockarg); 1966 1967 /* 1968 * If we unlock the list lock (and set KN_INFLUX), we can 1969 * eliminate the kqueue scheduling, but this will introduce 1970 * four lock/unlock's for each knote to test. Also, marker 1971 * would be needed to keep iteration position, since filters 1972 * or other threads could remove events. 1973 */ 1974 SLIST_FOREACH_SAFE(kn, &list->kl_list, kn_selnext, tkn) { 1975 kq = kn->kn_kq; 1976 KQ_LOCK(kq); 1977 if ((kn->kn_status & (KN_INFLUX | KN_SCAN)) == KN_INFLUX) { 1978 /* 1979 * Do not process the influx notes, except for 1980 * the influx coming from the kq unlock in the 1981 * kqueue_scan(). In the later case, we do 1982 * not interfere with the scan, since the code 1983 * fragment in kqueue_scan() locks the knlist, 1984 * and cannot proceed until we finished. 1985 */ 1986 KQ_UNLOCK(kq); 1987 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1988 own_influx = (kn->kn_status & KN_INFLUX) == 0; 1989 if (own_influx) 1990 kn->kn_status |= KN_INFLUX; 1991 KQ_UNLOCK(kq); 1992 error = kn->kn_fop->f_event(kn, hint); 1993 KQ_LOCK(kq); 1994 if (own_influx) 1995 kn->kn_status &= ~KN_INFLUX; 1996 if (error) 1997 KNOTE_ACTIVATE(kn, 1); 1998 KQ_UNLOCK_FLUX(kq); 1999 } else { 2000 kn->kn_status |= KN_HASKQLOCK; 2001 if (kn->kn_fop->f_event(kn, hint)) 2002 KNOTE_ACTIVATE(kn, 1); 2003 kn->kn_status &= ~KN_HASKQLOCK; 2004 KQ_UNLOCK(kq); 2005 } 2006 } 2007 if ((lockflags & KNF_LISTLOCKED) == 0) 2008 list->kl_unlock(list->kl_lockarg); 2009 } 2010 2011 /* 2012 * add a knote to a knlist 2013 */ 2014 void 2015 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 2016 { 2017 KNL_ASSERT_LOCK(knl, islocked); 2018 KQ_NOTOWNED(kn->kn_kq); 2019 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 2020 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 2021 if (!islocked) 2022 knl->kl_lock(knl->kl_lockarg); 2023 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 2024 if (!islocked) 2025 knl->kl_unlock(knl->kl_lockarg); 2026 KQ_LOCK(kn->kn_kq); 2027 kn->kn_knlist = knl; 2028 kn->kn_status &= ~KN_DETACHED; 2029 KQ_UNLOCK(kn->kn_kq); 2030 } 2031 2032 static void 2033 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 2034 { 2035 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 2036 KNL_ASSERT_LOCK(knl, knlislocked); 2037 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 2038 if (!kqislocked) 2039 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 2040 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 2041 if (!knlislocked) 2042 knl->kl_lock(knl->kl_lockarg); 2043 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 2044 kn->kn_knlist = NULL; 2045 if (!knlislocked) 2046 knl->kl_unlock(knl->kl_lockarg); 2047 if (!kqislocked) 2048 KQ_LOCK(kn->kn_kq); 2049 kn->kn_status |= KN_DETACHED; 2050 if (!kqislocked) 2051 KQ_UNLOCK(kn->kn_kq); 2052 } 2053 2054 /* 2055 * remove knote from the specified knlist 2056 */ 2057 void 2058 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 2059 { 2060 2061 knlist_remove_kq(knl, kn, islocked, 0); 2062 } 2063 2064 /* 2065 * remove knote from the specified knlist while in f_event handler. 2066 */ 2067 void 2068 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 2069 { 2070 2071 knlist_remove_kq(knl, kn, 1, 2072 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 2073 } 2074 2075 int 2076 knlist_empty(struct knlist *knl) 2077 { 2078 2079 KNL_ASSERT_LOCKED(knl); 2080 return (SLIST_EMPTY(&knl->kl_list)); 2081 } 2082 2083 static struct mtx knlist_lock; 2084 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 2085 MTX_DEF); 2086 static void knlist_mtx_lock(void *arg); 2087 static void knlist_mtx_unlock(void *arg); 2088 2089 static void 2090 knlist_mtx_lock(void *arg) 2091 { 2092 2093 mtx_lock((struct mtx *)arg); 2094 } 2095 2096 static void 2097 knlist_mtx_unlock(void *arg) 2098 { 2099 2100 mtx_unlock((struct mtx *)arg); 2101 } 2102 2103 static void 2104 knlist_mtx_assert_locked(void *arg) 2105 { 2106 2107 mtx_assert((struct mtx *)arg, MA_OWNED); 2108 } 2109 2110 static void 2111 knlist_mtx_assert_unlocked(void *arg) 2112 { 2113 2114 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 2115 } 2116 2117 static void 2118 knlist_rw_rlock(void *arg) 2119 { 2120 2121 rw_rlock((struct rwlock *)arg); 2122 } 2123 2124 static void 2125 knlist_rw_runlock(void *arg) 2126 { 2127 2128 rw_runlock((struct rwlock *)arg); 2129 } 2130 2131 static void 2132 knlist_rw_assert_locked(void *arg) 2133 { 2134 2135 rw_assert((struct rwlock *)arg, RA_LOCKED); 2136 } 2137 2138 static void 2139 knlist_rw_assert_unlocked(void *arg) 2140 { 2141 2142 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2143 } 2144 2145 void 2146 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2147 void (*kl_unlock)(void *), 2148 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2149 { 2150 2151 if (lock == NULL) 2152 knl->kl_lockarg = &knlist_lock; 2153 else 2154 knl->kl_lockarg = lock; 2155 2156 if (kl_lock == NULL) 2157 knl->kl_lock = knlist_mtx_lock; 2158 else 2159 knl->kl_lock = kl_lock; 2160 if (kl_unlock == NULL) 2161 knl->kl_unlock = knlist_mtx_unlock; 2162 else 2163 knl->kl_unlock = kl_unlock; 2164 if (kl_assert_locked == NULL) 2165 knl->kl_assert_locked = knlist_mtx_assert_locked; 2166 else 2167 knl->kl_assert_locked = kl_assert_locked; 2168 if (kl_assert_unlocked == NULL) 2169 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2170 else 2171 knl->kl_assert_unlocked = kl_assert_unlocked; 2172 2173 SLIST_INIT(&knl->kl_list); 2174 } 2175 2176 void 2177 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2178 { 2179 2180 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2181 } 2182 2183 void 2184 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2185 { 2186 2187 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2188 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2189 } 2190 2191 void 2192 knlist_destroy(struct knlist *knl) 2193 { 2194 2195 KASSERT(KNLIST_EMPTY(knl), 2196 ("destroying knlist %p with knotes on it", knl)); 2197 } 2198 2199 /* 2200 * Even if we are locked, we may need to drop the lock to allow any influx 2201 * knotes time to "settle". 2202 */ 2203 void 2204 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2205 { 2206 struct knote *kn, *kn2; 2207 struct kqueue *kq; 2208 2209 if (islocked) 2210 KNL_ASSERT_LOCKED(knl); 2211 else { 2212 KNL_ASSERT_UNLOCKED(knl); 2213 again: /* need to reacquire lock since we have dropped it */ 2214 knl->kl_lock(knl->kl_lockarg); 2215 } 2216 2217 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2218 kq = kn->kn_kq; 2219 KQ_LOCK(kq); 2220 if ((kn->kn_status & KN_INFLUX)) { 2221 KQ_UNLOCK(kq); 2222 continue; 2223 } 2224 knlist_remove_kq(knl, kn, 1, 1); 2225 if (killkn) { 2226 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2227 KQ_UNLOCK(kq); 2228 knote_drop(kn, td); 2229 } else { 2230 /* Make sure cleared knotes disappear soon */ 2231 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2232 KQ_UNLOCK(kq); 2233 } 2234 kq = NULL; 2235 } 2236 2237 if (!SLIST_EMPTY(&knl->kl_list)) { 2238 /* there are still KN_INFLUX remaining */ 2239 kn = SLIST_FIRST(&knl->kl_list); 2240 kq = kn->kn_kq; 2241 KQ_LOCK(kq); 2242 KASSERT(kn->kn_status & KN_INFLUX, 2243 ("knote removed w/o list lock")); 2244 knl->kl_unlock(knl->kl_lockarg); 2245 kq->kq_state |= KQ_FLUXWAIT; 2246 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2247 kq = NULL; 2248 goto again; 2249 } 2250 2251 if (islocked) 2252 KNL_ASSERT_LOCKED(knl); 2253 else { 2254 knl->kl_unlock(knl->kl_lockarg); 2255 KNL_ASSERT_UNLOCKED(knl); 2256 } 2257 } 2258 2259 /* 2260 * Remove all knotes referencing a specified fd must be called with FILEDESC 2261 * lock. This prevents a race where a new fd comes along and occupies the 2262 * entry and we attach a knote to the fd. 2263 */ 2264 void 2265 knote_fdclose(struct thread *td, int fd) 2266 { 2267 struct filedesc *fdp = td->td_proc->p_fd; 2268 struct kqueue *kq; 2269 struct knote *kn; 2270 int influx; 2271 2272 FILEDESC_XLOCK_ASSERT(fdp); 2273 2274 /* 2275 * We shouldn't have to worry about new kevents appearing on fd 2276 * since filedesc is locked. 2277 */ 2278 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2279 KQ_LOCK(kq); 2280 2281 again: 2282 influx = 0; 2283 while (kq->kq_knlistsize > fd && 2284 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2285 if (kn->kn_status & KN_INFLUX) { 2286 /* someone else might be waiting on our knote */ 2287 if (influx) 2288 wakeup(kq); 2289 kq->kq_state |= KQ_FLUXWAIT; 2290 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2291 goto again; 2292 } 2293 kn->kn_status |= KN_INFLUX; 2294 KQ_UNLOCK(kq); 2295 if (!(kn->kn_status & KN_DETACHED)) 2296 kn->kn_fop->f_detach(kn); 2297 knote_drop(kn, td); 2298 influx = 1; 2299 KQ_LOCK(kq); 2300 } 2301 KQ_UNLOCK_FLUX(kq); 2302 } 2303 } 2304 2305 static int 2306 knote_attach(struct knote *kn, struct kqueue *kq) 2307 { 2308 struct klist *list; 2309 2310 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2311 KQ_OWNED(kq); 2312 2313 if (kn->kn_fop->f_isfd) { 2314 if (kn->kn_id >= kq->kq_knlistsize) 2315 return (ENOMEM); 2316 list = &kq->kq_knlist[kn->kn_id]; 2317 } else { 2318 if (kq->kq_knhash == NULL) 2319 return (ENOMEM); 2320 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2321 } 2322 SLIST_INSERT_HEAD(list, kn, kn_link); 2323 return (0); 2324 } 2325 2326 /* 2327 * knote must already have been detached using the f_detach method. 2328 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2329 * to prevent other removal. 2330 */ 2331 static void 2332 knote_drop(struct knote *kn, struct thread *td) 2333 { 2334 struct kqueue *kq; 2335 struct klist *list; 2336 2337 kq = kn->kn_kq; 2338 2339 KQ_NOTOWNED(kq); 2340 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2341 ("knote_drop called without KN_INFLUX set in kn_status")); 2342 2343 KQ_LOCK(kq); 2344 if (kn->kn_fop->f_isfd) 2345 list = &kq->kq_knlist[kn->kn_id]; 2346 else 2347 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2348 2349 if (!SLIST_EMPTY(list)) 2350 SLIST_REMOVE(list, kn, knote, kn_link); 2351 if (kn->kn_status & KN_QUEUED) 2352 knote_dequeue(kn); 2353 KQ_UNLOCK_FLUX(kq); 2354 2355 if (kn->kn_fop->f_isfd) { 2356 fdrop(kn->kn_fp, td); 2357 kn->kn_fp = NULL; 2358 } 2359 kqueue_fo_release(kn->kn_kevent.filter); 2360 kn->kn_fop = NULL; 2361 knote_free(kn); 2362 } 2363 2364 static void 2365 knote_enqueue(struct knote *kn) 2366 { 2367 struct kqueue *kq = kn->kn_kq; 2368 2369 KQ_OWNED(kn->kn_kq); 2370 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2371 2372 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2373 kn->kn_status |= KN_QUEUED; 2374 kq->kq_count++; 2375 kqueue_wakeup(kq); 2376 } 2377 2378 static void 2379 knote_dequeue(struct knote *kn) 2380 { 2381 struct kqueue *kq = kn->kn_kq; 2382 2383 KQ_OWNED(kn->kn_kq); 2384 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2385 2386 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2387 kn->kn_status &= ~KN_QUEUED; 2388 kq->kq_count--; 2389 } 2390 2391 static void 2392 knote_init(void) 2393 { 2394 2395 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2396 NULL, NULL, UMA_ALIGN_PTR, 0); 2397 } 2398 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2399 2400 static struct knote * 2401 knote_alloc(int waitok) 2402 { 2403 return ((struct knote *)uma_zalloc(knote_zone, 2404 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2405 } 2406 2407 static void 2408 knote_free(struct knote *kn) 2409 { 2410 if (kn != NULL) 2411 uma_zfree(knote_zone, kn); 2412 } 2413 2414 /* 2415 * Register the kev w/ the kq specified by fd. 2416 */ 2417 int 2418 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2419 { 2420 struct kqueue *kq; 2421 struct file *fp; 2422 cap_rights_t rights; 2423 int error; 2424 2425 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2426 if (error != 0) 2427 return (error); 2428 if ((error = kqueue_acquire(fp, &kq)) != 0) 2429 goto noacquire; 2430 2431 error = kqueue_register(kq, kev, td, waitok); 2432 kqueue_release(kq, 0); 2433 2434 noacquire: 2435 fdrop(fp, td); 2436 return (error); 2437 }
Cache object: d68329ed61ca7c967bb03f4e8c15e8fd
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