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