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