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