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