1 /*- 2 * Copyright (c) 1999,2000,2001 Jonathan Lemon <jlemon@FreeBSD.org> 3 * Copyright 2004 John-Mark Gurney <jmg@FreeBSD.org> 4 * Copyright (c) 2009 Apple, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 __FBSDID("$FreeBSD$"); 31 32 #include "opt_ktrace.h" 33 34 #include <sys/param.h> 35 #include <sys/systm.h> 36 #include <sys/capability.h> 37 #include <sys/kernel.h> 38 #include <sys/lock.h> 39 #include <sys/mutex.h> 40 #include <sys/rwlock.h> 41 #include <sys/proc.h> 42 #include <sys/malloc.h> 43 #include <sys/unistd.h> 44 #include <sys/file.h> 45 #include <sys/filedesc.h> 46 #include <sys/filio.h> 47 #include <sys/fcntl.h> 48 #include <sys/kthread.h> 49 #include <sys/selinfo.h> 50 #include <sys/stdatomic.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 #ifdef KTRACE 68 #include <sys/ktrace.h> 69 #endif 70 71 #include <vm/uma.h> 72 73 static MALLOC_DEFINE(M_KQUEUE, "kqueue", "memory for kqueue system"); 74 75 /* 76 * This lock is used if multiple kq locks are required. This possibly 77 * should be made into a per proc lock. 78 */ 79 static struct mtx kq_global; 80 MTX_SYSINIT(kq_global, &kq_global, "kqueue order", MTX_DEF); 81 #define KQ_GLOBAL_LOCK(lck, haslck) do { \ 82 if (!haslck) \ 83 mtx_lock(lck); \ 84 haslck = 1; \ 85 } while (0) 86 #define KQ_GLOBAL_UNLOCK(lck, haslck) do { \ 87 if (haslck) \ 88 mtx_unlock(lck); \ 89 haslck = 0; \ 90 } while (0) 91 92 TASKQUEUE_DEFINE_THREAD(kqueue); 93 94 static int kevent_copyout(void *arg, struct kevent *kevp, int count); 95 static int kevent_copyin(void *arg, struct kevent *kevp, int count); 96 static int kqueue_register(struct kqueue *kq, struct kevent *kev, 97 struct thread *td, int waitok); 98 static int kqueue_acquire(struct file *fp, struct kqueue **kqp); 99 static void kqueue_release(struct kqueue *kq, int locked); 100 static int kqueue_expand(struct kqueue *kq, struct filterops *fops, 101 uintptr_t ident, int waitok); 102 static void kqueue_task(void *arg, int pending); 103 static int kqueue_scan(struct kqueue *kq, int maxevents, 104 struct kevent_copyops *k_ops, 105 const struct timespec *timeout, 106 struct kevent *keva, struct thread *td); 107 static void kqueue_wakeup(struct kqueue *kq); 108 static struct filterops *kqueue_fo_find(int filt); 109 static void kqueue_fo_release(int filt); 110 111 static fo_rdwr_t kqueue_read; 112 static fo_rdwr_t kqueue_write; 113 static fo_truncate_t kqueue_truncate; 114 static fo_ioctl_t kqueue_ioctl; 115 static fo_poll_t kqueue_poll; 116 static fo_kqfilter_t kqueue_kqfilter; 117 static fo_stat_t kqueue_stat; 118 static fo_close_t kqueue_close; 119 120 static struct fileops kqueueops = { 121 .fo_read = kqueue_read, 122 .fo_write = kqueue_write, 123 .fo_truncate = kqueue_truncate, 124 .fo_ioctl = kqueue_ioctl, 125 .fo_poll = kqueue_poll, 126 .fo_kqfilter = kqueue_kqfilter, 127 .fo_stat = kqueue_stat, 128 .fo_close = kqueue_close, 129 .fo_chmod = invfo_chmod, 130 .fo_chown = invfo_chown, 131 .fo_sendfile = invfo_sendfile, 132 }; 133 134 static int knote_attach(struct knote *kn, struct kqueue *kq); 135 static void knote_drop(struct knote *kn, struct thread *td); 136 static void knote_enqueue(struct knote *kn); 137 static void knote_dequeue(struct knote *kn); 138 static void knote_init(void); 139 static struct knote *knote_alloc(int waitok); 140 static void knote_free(struct knote *kn); 141 142 static void filt_kqdetach(struct knote *kn); 143 static int filt_kqueue(struct knote *kn, long hint); 144 static int filt_procattach(struct knote *kn); 145 static void filt_procdetach(struct knote *kn); 146 static int filt_proc(struct knote *kn, long hint); 147 static int filt_fileattach(struct knote *kn); 148 static void filt_timerexpire(void *knx); 149 static int filt_timerattach(struct knote *kn); 150 static void filt_timerdetach(struct knote *kn); 151 static int filt_timer(struct knote *kn, long hint); 152 static int filt_userattach(struct knote *kn); 153 static void filt_userdetach(struct knote *kn); 154 static int filt_user(struct knote *kn, long hint); 155 static void filt_usertouch(struct knote *kn, struct kevent *kev, 156 u_long type); 157 158 static struct filterops file_filtops = { 159 .f_isfd = 1, 160 .f_attach = filt_fileattach, 161 }; 162 static struct filterops kqread_filtops = { 163 .f_isfd = 1, 164 .f_detach = filt_kqdetach, 165 .f_event = filt_kqueue, 166 }; 167 /* XXX - move to kern_proc.c? */ 168 static struct filterops proc_filtops = { 169 .f_isfd = 0, 170 .f_attach = filt_procattach, 171 .f_detach = filt_procdetach, 172 .f_event = filt_proc, 173 }; 174 static struct filterops timer_filtops = { 175 .f_isfd = 0, 176 .f_attach = filt_timerattach, 177 .f_detach = filt_timerdetach, 178 .f_event = filt_timer, 179 }; 180 static struct filterops user_filtops = { 181 .f_attach = filt_userattach, 182 .f_detach = filt_userdetach, 183 .f_event = filt_user, 184 .f_touch = filt_usertouch, 185 }; 186 187 static uma_zone_t knote_zone; 188 static atomic_uint kq_ncallouts = ATOMIC_VAR_INIT(0); 189 static unsigned int kq_calloutmax = 4 * 1024; 190 SYSCTL_UINT(_kern, OID_AUTO, kq_calloutmax, CTLFLAG_RW, 191 &kq_calloutmax, 0, "Maximum number of callouts allocated for kqueue"); 192 193 /* XXX - ensure not KN_INFLUX?? */ 194 #define KNOTE_ACTIVATE(kn, islock) do { \ 195 if ((islock)) \ 196 mtx_assert(&(kn)->kn_kq->kq_lock, MA_OWNED); \ 197 else \ 198 KQ_LOCK((kn)->kn_kq); \ 199 (kn)->kn_status |= KN_ACTIVE; \ 200 if (((kn)->kn_status & (KN_QUEUED | KN_DISABLED)) == 0) \ 201 knote_enqueue((kn)); \ 202 if (!(islock)) \ 203 KQ_UNLOCK((kn)->kn_kq); \ 204 } while(0) 205 #define KQ_LOCK(kq) do { \ 206 mtx_lock(&(kq)->kq_lock); \ 207 } while (0) 208 #define KQ_FLUX_WAKEUP(kq) do { \ 209 if (((kq)->kq_state & KQ_FLUXWAIT) == KQ_FLUXWAIT) { \ 210 (kq)->kq_state &= ~KQ_FLUXWAIT; \ 211 wakeup((kq)); \ 212 } \ 213 } while (0) 214 #define KQ_UNLOCK_FLUX(kq) do { \ 215 KQ_FLUX_WAKEUP(kq); \ 216 mtx_unlock(&(kq)->kq_lock); \ 217 } while (0) 218 #define KQ_UNLOCK(kq) do { \ 219 mtx_unlock(&(kq)->kq_lock); \ 220 } while (0) 221 #define KQ_OWNED(kq) do { \ 222 mtx_assert(&(kq)->kq_lock, MA_OWNED); \ 223 } while (0) 224 #define KQ_NOTOWNED(kq) do { \ 225 mtx_assert(&(kq)->kq_lock, MA_NOTOWNED); \ 226 } while (0) 227 #define KN_LIST_LOCK(kn) do { \ 228 if (kn->kn_knlist != NULL) \ 229 kn->kn_knlist->kl_lock(kn->kn_knlist->kl_lockarg); \ 230 } while (0) 231 #define KN_LIST_UNLOCK(kn) do { \ 232 if (kn->kn_knlist != NULL) \ 233 kn->kn_knlist->kl_unlock(kn->kn_knlist->kl_lockarg); \ 234 } while (0) 235 #define KNL_ASSERT_LOCK(knl, islocked) do { \ 236 if (islocked) \ 237 KNL_ASSERT_LOCKED(knl); \ 238 else \ 239 KNL_ASSERT_UNLOCKED(knl); \ 240 } while (0) 241 #ifdef INVARIANTS 242 #define KNL_ASSERT_LOCKED(knl) do { \ 243 knl->kl_assert_locked((knl)->kl_lockarg); \ 244 } while (0) 245 #define KNL_ASSERT_UNLOCKED(knl) do { \ 246 knl->kl_assert_unlocked((knl)->kl_lockarg); \ 247 } while (0) 248 #else /* !INVARIANTS */ 249 #define KNL_ASSERT_LOCKED(knl) do {} while(0) 250 #define KNL_ASSERT_UNLOCKED(knl) do {} while (0) 251 #endif /* INVARIANTS */ 252 253 #define KN_HASHSIZE 64 /* XXX should be tunable */ 254 #define KN_HASH(val, mask) (((val) ^ (val >> 8)) & (mask)) 255 256 static int 257 filt_nullattach(struct knote *kn) 258 { 259 260 return (ENXIO); 261 }; 262 263 struct filterops null_filtops = { 264 .f_isfd = 0, 265 .f_attach = filt_nullattach, 266 }; 267 268 /* XXX - make SYSINIT to add these, and move into respective modules. */ 269 extern struct filterops sig_filtops; 270 extern struct filterops fs_filtops; 271 272 /* 273 * Table for for all system-defined filters. 274 */ 275 static struct mtx filterops_lock; 276 MTX_SYSINIT(kqueue_filterops, &filterops_lock, "protect sysfilt_ops", 277 MTX_DEF); 278 static struct { 279 struct filterops *for_fop; 280 int for_refcnt; 281 } sysfilt_ops[EVFILT_SYSCOUNT] = { 282 { &file_filtops }, /* EVFILT_READ */ 283 { &file_filtops }, /* EVFILT_WRITE */ 284 { &null_filtops }, /* EVFILT_AIO */ 285 { &file_filtops }, /* EVFILT_VNODE */ 286 { &proc_filtops }, /* EVFILT_PROC */ 287 { &sig_filtops }, /* EVFILT_SIGNAL */ 288 { &timer_filtops }, /* EVFILT_TIMER */ 289 { &null_filtops }, /* former EVFILT_NETDEV */ 290 { &fs_filtops }, /* EVFILT_FS */ 291 { &null_filtops }, /* EVFILT_LIO */ 292 { &user_filtops }, /* EVFILT_USER */ 293 }; 294 295 /* 296 * Simple redirection for all cdevsw style objects to call their fo_kqfilter 297 * method. 298 */ 299 static int 300 filt_fileattach(struct knote *kn) 301 { 302 303 return (fo_kqfilter(kn->kn_fp, kn)); 304 } 305 306 /*ARGSUSED*/ 307 static int 308 kqueue_kqfilter(struct file *fp, struct knote *kn) 309 { 310 struct kqueue *kq = kn->kn_fp->f_data; 311 312 if (kn->kn_filter != EVFILT_READ) 313 return (EINVAL); 314 315 kn->kn_status |= KN_KQUEUE; 316 kn->kn_fop = &kqread_filtops; 317 knlist_add(&kq->kq_sel.si_note, kn, 0); 318 319 return (0); 320 } 321 322 static void 323 filt_kqdetach(struct knote *kn) 324 { 325 struct kqueue *kq = kn->kn_fp->f_data; 326 327 knlist_remove(&kq->kq_sel.si_note, kn, 0); 328 } 329 330 /*ARGSUSED*/ 331 static int 332 filt_kqueue(struct knote *kn, long hint) 333 { 334 struct kqueue *kq = kn->kn_fp->f_data; 335 336 kn->kn_data = kq->kq_count; 337 return (kn->kn_data > 0); 338 } 339 340 /* XXX - move to kern_proc.c? */ 341 static int 342 filt_procattach(struct knote *kn) 343 { 344 struct proc *p; 345 int immediate; 346 int error; 347 348 immediate = 0; 349 p = pfind(kn->kn_id); 350 if (p == NULL && (kn->kn_sfflags & NOTE_EXIT)) { 351 p = zpfind(kn->kn_id); 352 immediate = 1; 353 } else if (p != NULL && (p->p_flag & P_WEXIT)) { 354 immediate = 1; 355 } 356 357 if (p == NULL) 358 return (ESRCH); 359 if ((error = p_cansee(curthread, p))) { 360 PROC_UNLOCK(p); 361 return (error); 362 } 363 364 kn->kn_ptr.p_proc = p; 365 kn->kn_flags |= EV_CLEAR; /* automatically set */ 366 367 /* 368 * internal flag indicating registration done by kernel 369 */ 370 if (kn->kn_flags & EV_FLAG1) { 371 kn->kn_data = kn->kn_sdata; /* ppid */ 372 kn->kn_fflags = NOTE_CHILD; 373 kn->kn_flags &= ~EV_FLAG1; 374 } 375 376 if (immediate == 0) 377 knlist_add(&p->p_klist, kn, 1); 378 379 /* 380 * Immediately activate any exit notes if the target process is a 381 * zombie. This is necessary to handle the case where the target 382 * process, e.g. a child, dies before the kevent is registered. 383 */ 384 if (immediate && filt_proc(kn, NOTE_EXIT)) 385 KNOTE_ACTIVATE(kn, 0); 386 387 PROC_UNLOCK(p); 388 389 return (0); 390 } 391 392 /* 393 * The knote may be attached to a different process, which may exit, 394 * leaving nothing for the knote to be attached to. So when the process 395 * exits, the knote is marked as DETACHED and also flagged as ONESHOT so 396 * it will be deleted when read out. However, as part of the knote deletion, 397 * this routine is called, so a check is needed to avoid actually performing 398 * a detach, because the original process does not exist any more. 399 */ 400 /* XXX - move to kern_proc.c? */ 401 static void 402 filt_procdetach(struct knote *kn) 403 { 404 struct proc *p; 405 406 p = kn->kn_ptr.p_proc; 407 knlist_remove(&p->p_klist, kn, 0); 408 kn->kn_ptr.p_proc = NULL; 409 } 410 411 /* XXX - move to kern_proc.c? */ 412 static int 413 filt_proc(struct knote *kn, long hint) 414 { 415 struct proc *p = kn->kn_ptr.p_proc; 416 u_int event; 417 418 /* 419 * mask off extra data 420 */ 421 event = (u_int)hint & NOTE_PCTRLMASK; 422 423 /* 424 * if the user is interested in this event, record it. 425 */ 426 if (kn->kn_sfflags & event) 427 kn->kn_fflags |= event; 428 429 /* 430 * process is gone, so flag the event as finished. 431 */ 432 if (event == NOTE_EXIT) { 433 if (!(kn->kn_status & KN_DETACHED)) 434 knlist_remove_inevent(&p->p_klist, kn); 435 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 436 kn->kn_ptr.p_proc = NULL; 437 if (kn->kn_fflags & NOTE_EXIT) 438 kn->kn_data = p->p_xstat; 439 if (kn->kn_fflags == 0) 440 kn->kn_flags |= EV_DROP; 441 return (1); 442 } 443 444 return (kn->kn_fflags != 0); 445 } 446 447 /* 448 * Called when the process forked. It mostly does the same as the 449 * knote(), activating all knotes registered to be activated when the 450 * process forked. Additionally, for each knote attached to the 451 * parent, check whether user wants to track the new process. If so 452 * attach a new knote to it, and immediately report an event with the 453 * child's pid. 454 */ 455 void 456 knote_fork(struct knlist *list, int pid) 457 { 458 struct kqueue *kq; 459 struct knote *kn; 460 struct kevent kev; 461 int error; 462 463 if (list == NULL) 464 return; 465 list->kl_lock(list->kl_lockarg); 466 467 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 468 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) 469 continue; 470 kq = kn->kn_kq; 471 KQ_LOCK(kq); 472 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 473 KQ_UNLOCK(kq); 474 continue; 475 } 476 477 /* 478 * The same as knote(), activate the event. 479 */ 480 if ((kn->kn_sfflags & NOTE_TRACK) == 0) { 481 kn->kn_status |= KN_HASKQLOCK; 482 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 483 KNOTE_ACTIVATE(kn, 1); 484 kn->kn_status &= ~KN_HASKQLOCK; 485 KQ_UNLOCK(kq); 486 continue; 487 } 488 489 /* 490 * The NOTE_TRACK case. In addition to the activation 491 * of the event, we need to register new event to 492 * track the child. Drop the locks in preparation for 493 * the call to kqueue_register(). 494 */ 495 kn->kn_status |= KN_INFLUX; 496 KQ_UNLOCK(kq); 497 list->kl_unlock(list->kl_lockarg); 498 499 /* 500 * Activate existing knote and register a knote with 501 * new process. 502 */ 503 kev.ident = pid; 504 kev.filter = kn->kn_filter; 505 kev.flags = kn->kn_flags | EV_ADD | EV_ENABLE | EV_FLAG1; 506 kev.fflags = kn->kn_sfflags; 507 kev.data = kn->kn_id; /* parent */ 508 kev.udata = kn->kn_kevent.udata;/* preserve udata */ 509 error = kqueue_register(kq, &kev, NULL, 0); 510 if (error) 511 kn->kn_fflags |= NOTE_TRACKERR; 512 if (kn->kn_fop->f_event(kn, NOTE_FORK)) 513 KNOTE_ACTIVATE(kn, 0); 514 KQ_LOCK(kq); 515 kn->kn_status &= ~KN_INFLUX; 516 KQ_UNLOCK_FLUX(kq); 517 list->kl_lock(list->kl_lockarg); 518 } 519 list->kl_unlock(list->kl_lockarg); 520 } 521 522 /* 523 * XXX: EVFILT_TIMER should perhaps live in kern_time.c beside the 524 * interval timer support code. 525 */ 526 static __inline sbintime_t 527 timer2sbintime(intptr_t data) 528 { 529 530 #ifdef __LP64__ 531 if (data > INT64_MAX / SBT_1MS) 532 return INT64_MAX; 533 #endif 534 return (SBT_1MS * data); 535 } 536 537 static void 538 filt_timerexpire(void *knx) 539 { 540 struct callout *calloutp; 541 struct knote *kn; 542 543 kn = knx; 544 kn->kn_data++; 545 KNOTE_ACTIVATE(kn, 0); /* XXX - handle locking */ 546 547 if ((kn->kn_flags & EV_ONESHOT) != EV_ONESHOT) { 548 calloutp = (struct callout *)kn->kn_hook; 549 callout_reset_sbt_on(calloutp, 550 timer2sbintime(kn->kn_sdata), 0 /* 1ms? */, 551 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 552 } 553 } 554 555 /* 556 * data contains amount of time to sleep, in milliseconds 557 */ 558 static int 559 filt_timerattach(struct knote *kn) 560 { 561 struct callout *calloutp; 562 sbintime_t to; 563 unsigned int ncallouts; 564 565 if ((intptr_t)kn->kn_sdata < 0) 566 return (EINVAL); 567 if ((intptr_t)kn->kn_sdata == 0 && (kn->kn_flags & EV_ONESHOT) == 0) 568 kn->kn_sdata = 1; 569 to = timer2sbintime(kn->kn_sdata); 570 if (to < 0) 571 return (EINVAL); 572 573 ncallouts = atomic_load_explicit(&kq_ncallouts, memory_order_relaxed); 574 do { 575 if (ncallouts >= kq_calloutmax) 576 return (ENOMEM); 577 } while (!atomic_compare_exchange_weak_explicit(&kq_ncallouts, 578 &ncallouts, ncallouts + 1, memory_order_relaxed, 579 memory_order_relaxed)); 580 581 kn->kn_flags |= EV_CLEAR; /* automatically set */ 582 kn->kn_status &= ~KN_DETACHED; /* knlist_add clears it */ 583 calloutp = malloc(sizeof(*calloutp), M_KQUEUE, M_WAITOK); 584 callout_init(calloutp, CALLOUT_MPSAFE); 585 kn->kn_hook = calloutp; 586 callout_reset_sbt_on(calloutp, to, 0 /* 1ms? */, 587 filt_timerexpire, kn, PCPU_GET(cpuid), 0); 588 589 return (0); 590 } 591 592 static void 593 filt_timerdetach(struct knote *kn) 594 { 595 struct callout *calloutp; 596 unsigned int old; 597 598 calloutp = (struct callout *)kn->kn_hook; 599 callout_drain(calloutp); 600 free(calloutp, M_KQUEUE); 601 old = atomic_fetch_sub_explicit(&kq_ncallouts, 1, memory_order_relaxed); 602 KASSERT(old > 0, ("Number of callouts cannot become negative")); 603 kn->kn_status |= KN_DETACHED; /* knlist_remove sets it */ 604 } 605 606 static int 607 filt_timer(struct knote *kn, long hint) 608 { 609 610 return (kn->kn_data != 0); 611 } 612 613 static int 614 filt_userattach(struct knote *kn) 615 { 616 617 /* 618 * EVFILT_USER knotes are not attached to anything in the kernel. 619 */ 620 kn->kn_hook = NULL; 621 if (kn->kn_fflags & NOTE_TRIGGER) 622 kn->kn_hookid = 1; 623 else 624 kn->kn_hookid = 0; 625 return (0); 626 } 627 628 static void 629 filt_userdetach(__unused struct knote *kn) 630 { 631 632 /* 633 * EVFILT_USER knotes are not attached to anything in the kernel. 634 */ 635 } 636 637 static int 638 filt_user(struct knote *kn, __unused long hint) 639 { 640 641 return (kn->kn_hookid); 642 } 643 644 static void 645 filt_usertouch(struct knote *kn, struct kevent *kev, u_long type) 646 { 647 u_int ffctrl; 648 649 switch (type) { 650 case EVENT_REGISTER: 651 if (kev->fflags & NOTE_TRIGGER) 652 kn->kn_hookid = 1; 653 654 ffctrl = kev->fflags & NOTE_FFCTRLMASK; 655 kev->fflags &= NOTE_FFLAGSMASK; 656 switch (ffctrl) { 657 case NOTE_FFNOP: 658 break; 659 660 case NOTE_FFAND: 661 kn->kn_sfflags &= kev->fflags; 662 break; 663 664 case NOTE_FFOR: 665 kn->kn_sfflags |= kev->fflags; 666 break; 667 668 case NOTE_FFCOPY: 669 kn->kn_sfflags = kev->fflags; 670 break; 671 672 default: 673 /* XXX Return error? */ 674 break; 675 } 676 kn->kn_sdata = kev->data; 677 if (kev->flags & EV_CLEAR) { 678 kn->kn_hookid = 0; 679 kn->kn_data = 0; 680 kn->kn_fflags = 0; 681 } 682 break; 683 684 case EVENT_PROCESS: 685 *kev = kn->kn_kevent; 686 kev->fflags = kn->kn_sfflags; 687 kev->data = kn->kn_sdata; 688 if (kn->kn_flags & EV_CLEAR) { 689 kn->kn_hookid = 0; 690 kn->kn_data = 0; 691 kn->kn_fflags = 0; 692 } 693 break; 694 695 default: 696 panic("filt_usertouch() - invalid type (%ld)", type); 697 break; 698 } 699 } 700 701 int 702 sys_kqueue(struct thread *td, struct kqueue_args *uap) 703 { 704 struct filedesc *fdp; 705 struct kqueue *kq; 706 struct file *fp; 707 struct proc *p; 708 struct ucred *cred; 709 int fd, error; 710 711 p = td->td_proc; 712 cred = td->td_ucred; 713 crhold(cred); 714 PROC_LOCK(p); 715 if (!chgkqcnt(cred->cr_ruidinfo, 1, lim_cur(td->td_proc, 716 RLIMIT_KQUEUES))) { 717 PROC_UNLOCK(p); 718 crfree(cred); 719 return (ENOMEM); 720 } 721 PROC_UNLOCK(p); 722 723 fdp = p->p_fd; 724 error = falloc(td, &fp, &fd, 0); 725 if (error) 726 goto done2; 727 728 /* An extra reference on `fp' has been held for us by falloc(). */ 729 kq = malloc(sizeof *kq, M_KQUEUE, M_WAITOK | M_ZERO); 730 mtx_init(&kq->kq_lock, "kqueue", NULL, MTX_DEF|MTX_DUPOK); 731 TAILQ_INIT(&kq->kq_head); 732 kq->kq_fdp = fdp; 733 kq->kq_cred = cred; 734 knlist_init_mtx(&kq->kq_sel.si_note, &kq->kq_lock); 735 TASK_INIT(&kq->kq_task, 0, kqueue_task, kq); 736 737 FILEDESC_XLOCK(fdp); 738 TAILQ_INSERT_HEAD(&fdp->fd_kqlist, kq, kq_list); 739 FILEDESC_XUNLOCK(fdp); 740 741 finit(fp, FREAD | FWRITE, DTYPE_KQUEUE, kq, &kqueueops); 742 fdrop(fp, td); 743 744 td->td_retval[0] = fd; 745 done2: 746 if (error != 0) { 747 chgkqcnt(cred->cr_ruidinfo, -1, 0); 748 crfree(cred); 749 } 750 return (error); 751 } 752 753 #ifndef _SYS_SYSPROTO_H_ 754 struct kevent_args { 755 int fd; 756 const struct kevent *changelist; 757 int nchanges; 758 struct kevent *eventlist; 759 int nevents; 760 const struct timespec *timeout; 761 }; 762 #endif 763 int 764 sys_kevent(struct thread *td, struct kevent_args *uap) 765 { 766 struct timespec ts, *tsp; 767 struct kevent_copyops k_ops = { uap, 768 kevent_copyout, 769 kevent_copyin}; 770 int error; 771 #ifdef KTRACE 772 struct uio ktruio; 773 struct iovec ktriov; 774 struct uio *ktruioin = NULL; 775 struct uio *ktruioout = NULL; 776 #endif 777 778 if (uap->timeout != NULL) { 779 error = copyin(uap->timeout, &ts, sizeof(ts)); 780 if (error) 781 return (error); 782 tsp = &ts; 783 } else 784 tsp = NULL; 785 786 #ifdef KTRACE 787 if (KTRPOINT(td, KTR_GENIO)) { 788 ktriov.iov_base = uap->changelist; 789 ktriov.iov_len = uap->nchanges * sizeof(struct kevent); 790 ktruio = (struct uio){ .uio_iov = &ktriov, .uio_iovcnt = 1, 791 .uio_segflg = UIO_USERSPACE, .uio_rw = UIO_READ, 792 .uio_td = td }; 793 ktruioin = cloneuio(&ktruio); 794 ktriov.iov_base = uap->eventlist; 795 ktriov.iov_len = uap->nevents * sizeof(struct kevent); 796 ktruioout = cloneuio(&ktruio); 797 } 798 #endif 799 800 error = kern_kevent(td, uap->fd, uap->nchanges, uap->nevents, 801 &k_ops, tsp); 802 803 #ifdef KTRACE 804 if (ktruioin != NULL) { 805 ktruioin->uio_resid = uap->nchanges * sizeof(struct kevent); 806 ktrgenio(uap->fd, UIO_WRITE, ktruioin, 0); 807 ktruioout->uio_resid = td->td_retval[0] * sizeof(struct kevent); 808 ktrgenio(uap->fd, UIO_READ, ktruioout, error); 809 } 810 #endif 811 812 return (error); 813 } 814 815 /* 816 * Copy 'count' items into the destination list pointed to by uap->eventlist. 817 */ 818 static int 819 kevent_copyout(void *arg, struct kevent *kevp, int count) 820 { 821 struct kevent_args *uap; 822 int error; 823 824 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 825 uap = (struct kevent_args *)arg; 826 827 error = copyout(kevp, uap->eventlist, count * sizeof *kevp); 828 if (error == 0) 829 uap->eventlist += count; 830 return (error); 831 } 832 833 /* 834 * Copy 'count' items from the list pointed to by uap->changelist. 835 */ 836 static int 837 kevent_copyin(void *arg, struct kevent *kevp, int count) 838 { 839 struct kevent_args *uap; 840 int error; 841 842 KASSERT(count <= KQ_NEVENTS, ("count (%d) > KQ_NEVENTS", count)); 843 uap = (struct kevent_args *)arg; 844 845 error = copyin(uap->changelist, kevp, count * sizeof *kevp); 846 if (error == 0) 847 uap->changelist += count; 848 return (error); 849 } 850 851 int 852 kern_kevent(struct thread *td, int fd, int nchanges, int nevents, 853 struct kevent_copyops *k_ops, const struct timespec *timeout) 854 { 855 struct kevent keva[KQ_NEVENTS]; 856 struct kevent *kevp, *changes; 857 struct kqueue *kq; 858 struct file *fp; 859 cap_rights_t rights; 860 int i, n, nerrors, error; 861 862 cap_rights_init(&rights); 863 if (nchanges > 0) 864 cap_rights_set(&rights, CAP_KQUEUE_CHANGE); 865 if (nevents > 0) 866 cap_rights_set(&rights, CAP_KQUEUE_EVENT); 867 error = fget(td, fd, &rights, &fp); 868 if (error != 0) 869 return (error); 870 871 error = kqueue_acquire(fp, &kq); 872 if (error != 0) 873 goto done_norel; 874 875 nerrors = 0; 876 877 while (nchanges > 0) { 878 n = nchanges > KQ_NEVENTS ? KQ_NEVENTS : nchanges; 879 error = k_ops->k_copyin(k_ops->arg, keva, n); 880 if (error) 881 goto done; 882 changes = keva; 883 for (i = 0; i < n; i++) { 884 kevp = &changes[i]; 885 if (!kevp->filter) 886 continue; 887 kevp->flags &= ~EV_SYSFLAGS; 888 error = kqueue_register(kq, kevp, td, 1); 889 if (error || (kevp->flags & EV_RECEIPT)) { 890 if (nevents != 0) { 891 kevp->flags = EV_ERROR; 892 kevp->data = error; 893 (void) k_ops->k_copyout(k_ops->arg, 894 kevp, 1); 895 nevents--; 896 nerrors++; 897 } else { 898 goto done; 899 } 900 } 901 } 902 nchanges -= n; 903 } 904 if (nerrors) { 905 td->td_retval[0] = nerrors; 906 error = 0; 907 goto done; 908 } 909 910 error = kqueue_scan(kq, nevents, k_ops, timeout, keva, td); 911 done: 912 kqueue_release(kq, 0); 913 done_norel: 914 fdrop(fp, td); 915 return (error); 916 } 917 918 int 919 kqueue_add_filteropts(int filt, struct filterops *filtops) 920 { 921 int error; 922 923 error = 0; 924 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) { 925 printf( 926 "trying to add a filterop that is out of range: %d is beyond %d\n", 927 ~filt, EVFILT_SYSCOUNT); 928 return EINVAL; 929 } 930 mtx_lock(&filterops_lock); 931 if (sysfilt_ops[~filt].for_fop != &null_filtops && 932 sysfilt_ops[~filt].for_fop != NULL) 933 error = EEXIST; 934 else { 935 sysfilt_ops[~filt].for_fop = filtops; 936 sysfilt_ops[~filt].for_refcnt = 0; 937 } 938 mtx_unlock(&filterops_lock); 939 940 return (error); 941 } 942 943 int 944 kqueue_del_filteropts(int filt) 945 { 946 int error; 947 948 error = 0; 949 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 950 return EINVAL; 951 952 mtx_lock(&filterops_lock); 953 if (sysfilt_ops[~filt].for_fop == &null_filtops || 954 sysfilt_ops[~filt].for_fop == NULL) 955 error = EINVAL; 956 else if (sysfilt_ops[~filt].for_refcnt != 0) 957 error = EBUSY; 958 else { 959 sysfilt_ops[~filt].for_fop = &null_filtops; 960 sysfilt_ops[~filt].for_refcnt = 0; 961 } 962 mtx_unlock(&filterops_lock); 963 964 return error; 965 } 966 967 static struct filterops * 968 kqueue_fo_find(int filt) 969 { 970 971 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 972 return NULL; 973 974 mtx_lock(&filterops_lock); 975 sysfilt_ops[~filt].for_refcnt++; 976 if (sysfilt_ops[~filt].for_fop == NULL) 977 sysfilt_ops[~filt].for_fop = &null_filtops; 978 mtx_unlock(&filterops_lock); 979 980 return sysfilt_ops[~filt].for_fop; 981 } 982 983 static void 984 kqueue_fo_release(int filt) 985 { 986 987 if (filt > 0 || filt + EVFILT_SYSCOUNT < 0) 988 return; 989 990 mtx_lock(&filterops_lock); 991 KASSERT(sysfilt_ops[~filt].for_refcnt > 0, 992 ("filter object refcount not valid on release")); 993 sysfilt_ops[~filt].for_refcnt--; 994 mtx_unlock(&filterops_lock); 995 } 996 997 /* 998 * A ref to kq (obtained via kqueue_acquire) must be held. waitok will 999 * influence if memory allocation should wait. Make sure it is 0 if you 1000 * hold any mutexes. 1001 */ 1002 static int 1003 kqueue_register(struct kqueue *kq, struct kevent *kev, struct thread *td, int waitok) 1004 { 1005 struct filterops *fops; 1006 struct file *fp; 1007 struct knote *kn, *tkn; 1008 cap_rights_t rights; 1009 int error, filt, event; 1010 int haskqglobal, filedesc_unlock; 1011 1012 fp = NULL; 1013 kn = NULL; 1014 error = 0; 1015 haskqglobal = 0; 1016 filedesc_unlock = 0; 1017 1018 filt = kev->filter; 1019 fops = kqueue_fo_find(filt); 1020 if (fops == NULL) 1021 return EINVAL; 1022 1023 tkn = knote_alloc(waitok); /* prevent waiting with locks */ 1024 1025 findkn: 1026 if (fops->f_isfd) { 1027 KASSERT(td != NULL, ("td is NULL")); 1028 error = fget(td, kev->ident, 1029 cap_rights_init(&rights, CAP_EVENT), &fp); 1030 if (error) 1031 goto done; 1032 1033 if ((kev->flags & EV_ADD) == EV_ADD && kqueue_expand(kq, fops, 1034 kev->ident, 0) != 0) { 1035 /* try again */ 1036 fdrop(fp, td); 1037 fp = NULL; 1038 error = kqueue_expand(kq, fops, kev->ident, waitok); 1039 if (error) 1040 goto done; 1041 goto findkn; 1042 } 1043 1044 if (fp->f_type == DTYPE_KQUEUE) { 1045 /* 1046 * if we add some inteligence about what we are doing, 1047 * we should be able to support events on ourselves. 1048 * We need to know when we are doing this to prevent 1049 * getting both the knlist lock and the kq lock since 1050 * they are the same thing. 1051 */ 1052 if (fp->f_data == kq) { 1053 error = EINVAL; 1054 goto done; 1055 } 1056 1057 /* 1058 * Pre-lock the filedesc before the global 1059 * lock mutex, see the comment in 1060 * kqueue_close(). 1061 */ 1062 FILEDESC_XLOCK(td->td_proc->p_fd); 1063 filedesc_unlock = 1; 1064 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1065 } 1066 1067 KQ_LOCK(kq); 1068 if (kev->ident < kq->kq_knlistsize) { 1069 SLIST_FOREACH(kn, &kq->kq_knlist[kev->ident], kn_link) 1070 if (kev->filter == kn->kn_filter) 1071 break; 1072 } 1073 } else { 1074 if ((kev->flags & EV_ADD) == EV_ADD) 1075 kqueue_expand(kq, fops, kev->ident, waitok); 1076 1077 KQ_LOCK(kq); 1078 if (kq->kq_knhashmask != 0) { 1079 struct klist *list; 1080 1081 list = &kq->kq_knhash[ 1082 KN_HASH((u_long)kev->ident, kq->kq_knhashmask)]; 1083 SLIST_FOREACH(kn, list, kn_link) 1084 if (kev->ident == kn->kn_id && 1085 kev->filter == kn->kn_filter) 1086 break; 1087 } 1088 } 1089 1090 /* knote is in the process of changing, wait for it to stablize. */ 1091 if (kn != NULL && (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1092 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1093 if (filedesc_unlock) { 1094 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1095 filedesc_unlock = 0; 1096 } 1097 kq->kq_state |= KQ_FLUXWAIT; 1098 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqflxwt", 0); 1099 if (fp != NULL) { 1100 fdrop(fp, td); 1101 fp = NULL; 1102 } 1103 goto findkn; 1104 } 1105 1106 /* 1107 * kn now contains the matching knote, or NULL if no match 1108 */ 1109 if (kn == NULL) { 1110 if (kev->flags & EV_ADD) { 1111 kn = tkn; 1112 tkn = NULL; 1113 if (kn == NULL) { 1114 KQ_UNLOCK(kq); 1115 error = ENOMEM; 1116 goto done; 1117 } 1118 kn->kn_fp = fp; 1119 kn->kn_kq = kq; 1120 kn->kn_fop = fops; 1121 /* 1122 * apply reference counts to knote structure, and 1123 * do not release it at the end of this routine. 1124 */ 1125 fops = NULL; 1126 fp = NULL; 1127 1128 kn->kn_sfflags = kev->fflags; 1129 kn->kn_sdata = kev->data; 1130 kev->fflags = 0; 1131 kev->data = 0; 1132 kn->kn_kevent = *kev; 1133 kn->kn_kevent.flags &= ~(EV_ADD | EV_DELETE | 1134 EV_ENABLE | EV_DISABLE); 1135 kn->kn_status = KN_INFLUX|KN_DETACHED; 1136 1137 error = knote_attach(kn, kq); 1138 KQ_UNLOCK(kq); 1139 if (error != 0) { 1140 tkn = kn; 1141 goto done; 1142 } 1143 1144 if ((error = kn->kn_fop->f_attach(kn)) != 0) { 1145 knote_drop(kn, td); 1146 goto done; 1147 } 1148 KN_LIST_LOCK(kn); 1149 goto done_ev_add; 1150 } else { 1151 /* No matching knote and the EV_ADD flag is not set. */ 1152 KQ_UNLOCK(kq); 1153 error = ENOENT; 1154 goto done; 1155 } 1156 } 1157 1158 if (kev->flags & EV_DELETE) { 1159 kn->kn_status |= KN_INFLUX; 1160 KQ_UNLOCK(kq); 1161 if (!(kn->kn_status & KN_DETACHED)) 1162 kn->kn_fop->f_detach(kn); 1163 knote_drop(kn, td); 1164 goto done; 1165 } 1166 1167 /* 1168 * The user may change some filter values after the initial EV_ADD, 1169 * but doing so will not reset any filter which has already been 1170 * triggered. 1171 */ 1172 kn->kn_status |= KN_INFLUX; 1173 KQ_UNLOCK(kq); 1174 KN_LIST_LOCK(kn); 1175 kn->kn_kevent.udata = kev->udata; 1176 if (!fops->f_isfd && fops->f_touch != NULL) { 1177 fops->f_touch(kn, kev, EVENT_REGISTER); 1178 } else { 1179 kn->kn_sfflags = kev->fflags; 1180 kn->kn_sdata = kev->data; 1181 } 1182 1183 /* 1184 * We can get here with kn->kn_knlist == NULL. This can happen when 1185 * the initial attach event decides that the event is "completed" 1186 * already. i.e. filt_procattach is called on a zombie process. It 1187 * will call filt_proc which will remove it from the list, and NULL 1188 * kn_knlist. 1189 */ 1190 done_ev_add: 1191 event = kn->kn_fop->f_event(kn, 0); 1192 KQ_LOCK(kq); 1193 if (event) 1194 KNOTE_ACTIVATE(kn, 1); 1195 kn->kn_status &= ~KN_INFLUX; 1196 KN_LIST_UNLOCK(kn); 1197 1198 if ((kev->flags & EV_DISABLE) && 1199 ((kn->kn_status & KN_DISABLED) == 0)) { 1200 kn->kn_status |= KN_DISABLED; 1201 } 1202 1203 if ((kev->flags & EV_ENABLE) && (kn->kn_status & KN_DISABLED)) { 1204 kn->kn_status &= ~KN_DISABLED; 1205 if ((kn->kn_status & KN_ACTIVE) && 1206 ((kn->kn_status & KN_QUEUED) == 0)) 1207 knote_enqueue(kn); 1208 } 1209 KQ_UNLOCK_FLUX(kq); 1210 1211 done: 1212 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1213 if (filedesc_unlock) 1214 FILEDESC_XUNLOCK(td->td_proc->p_fd); 1215 if (fp != NULL) 1216 fdrop(fp, td); 1217 if (tkn != NULL) 1218 knote_free(tkn); 1219 if (fops != NULL) 1220 kqueue_fo_release(filt); 1221 return (error); 1222 } 1223 1224 static int 1225 kqueue_acquire(struct file *fp, struct kqueue **kqp) 1226 { 1227 int error; 1228 struct kqueue *kq; 1229 1230 error = 0; 1231 1232 kq = fp->f_data; 1233 if (fp->f_type != DTYPE_KQUEUE || kq == NULL) 1234 return (EBADF); 1235 *kqp = kq; 1236 KQ_LOCK(kq); 1237 if ((kq->kq_state & KQ_CLOSING) == KQ_CLOSING) { 1238 KQ_UNLOCK(kq); 1239 return (EBADF); 1240 } 1241 kq->kq_refcnt++; 1242 KQ_UNLOCK(kq); 1243 1244 return error; 1245 } 1246 1247 static void 1248 kqueue_release(struct kqueue *kq, int locked) 1249 { 1250 if (locked) 1251 KQ_OWNED(kq); 1252 else 1253 KQ_LOCK(kq); 1254 kq->kq_refcnt--; 1255 if (kq->kq_refcnt == 1) 1256 wakeup(&kq->kq_refcnt); 1257 if (!locked) 1258 KQ_UNLOCK(kq); 1259 } 1260 1261 static void 1262 kqueue_schedtask(struct kqueue *kq) 1263 { 1264 1265 KQ_OWNED(kq); 1266 KASSERT(((kq->kq_state & KQ_TASKDRAIN) != KQ_TASKDRAIN), 1267 ("scheduling kqueue task while draining")); 1268 1269 if ((kq->kq_state & KQ_TASKSCHED) != KQ_TASKSCHED) { 1270 taskqueue_enqueue(taskqueue_kqueue, &kq->kq_task); 1271 kq->kq_state |= KQ_TASKSCHED; 1272 } 1273 } 1274 1275 /* 1276 * Expand the kq to make sure we have storage for fops/ident pair. 1277 * 1278 * Return 0 on success (or no work necessary), return errno on failure. 1279 * 1280 * Not calling hashinit w/ waitok (proper malloc flag) should be safe. 1281 * If kqueue_register is called from a non-fd context, there usually/should 1282 * be no locks held. 1283 */ 1284 static int 1285 kqueue_expand(struct kqueue *kq, struct filterops *fops, uintptr_t ident, 1286 int waitok) 1287 { 1288 struct klist *list, *tmp_knhash, *to_free; 1289 u_long tmp_knhashmask; 1290 int size; 1291 int fd; 1292 int mflag = waitok ? M_WAITOK : M_NOWAIT; 1293 1294 KQ_NOTOWNED(kq); 1295 1296 to_free = NULL; 1297 if (fops->f_isfd) { 1298 fd = ident; 1299 if (kq->kq_knlistsize <= fd) { 1300 size = kq->kq_knlistsize; 1301 while (size <= fd) 1302 size += KQEXTENT; 1303 list = malloc(size * sizeof(*list), M_KQUEUE, mflag); 1304 if (list == NULL) 1305 return ENOMEM; 1306 KQ_LOCK(kq); 1307 if (kq->kq_knlistsize > fd) { 1308 to_free = list; 1309 list = NULL; 1310 } else { 1311 if (kq->kq_knlist != NULL) { 1312 bcopy(kq->kq_knlist, list, 1313 kq->kq_knlistsize * sizeof(*list)); 1314 to_free = kq->kq_knlist; 1315 kq->kq_knlist = NULL; 1316 } 1317 bzero((caddr_t)list + 1318 kq->kq_knlistsize * sizeof(*list), 1319 (size - kq->kq_knlistsize) * sizeof(*list)); 1320 kq->kq_knlistsize = size; 1321 kq->kq_knlist = list; 1322 } 1323 KQ_UNLOCK(kq); 1324 } 1325 } else { 1326 if (kq->kq_knhashmask == 0) { 1327 tmp_knhash = hashinit(KN_HASHSIZE, M_KQUEUE, 1328 &tmp_knhashmask); 1329 if (tmp_knhash == NULL) 1330 return ENOMEM; 1331 KQ_LOCK(kq); 1332 if (kq->kq_knhashmask == 0) { 1333 kq->kq_knhash = tmp_knhash; 1334 kq->kq_knhashmask = tmp_knhashmask; 1335 } else { 1336 to_free = tmp_knhash; 1337 } 1338 KQ_UNLOCK(kq); 1339 } 1340 } 1341 free(to_free, M_KQUEUE); 1342 1343 KQ_NOTOWNED(kq); 1344 return 0; 1345 } 1346 1347 static void 1348 kqueue_task(void *arg, int pending) 1349 { 1350 struct kqueue *kq; 1351 int haskqglobal; 1352 1353 haskqglobal = 0; 1354 kq = arg; 1355 1356 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1357 KQ_LOCK(kq); 1358 1359 KNOTE_LOCKED(&kq->kq_sel.si_note, 0); 1360 1361 kq->kq_state &= ~KQ_TASKSCHED; 1362 if ((kq->kq_state & KQ_TASKDRAIN) == KQ_TASKDRAIN) { 1363 wakeup(&kq->kq_state); 1364 } 1365 KQ_UNLOCK(kq); 1366 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1367 } 1368 1369 /* 1370 * Scan, update kn_data (if not ONESHOT), and copyout triggered events. 1371 * We treat KN_MARKER knotes as if they are INFLUX. 1372 */ 1373 static int 1374 kqueue_scan(struct kqueue *kq, int maxevents, struct kevent_copyops *k_ops, 1375 const struct timespec *tsp, struct kevent *keva, struct thread *td) 1376 { 1377 struct kevent *kevp; 1378 struct knote *kn, *marker; 1379 sbintime_t asbt, rsbt; 1380 int count, error, haskqglobal, influx, nkev, touch; 1381 1382 count = maxevents; 1383 nkev = 0; 1384 error = 0; 1385 haskqglobal = 0; 1386 1387 if (maxevents == 0) 1388 goto done_nl; 1389 1390 rsbt = 0; 1391 if (tsp != NULL) { 1392 if (tsp->tv_sec < 0 || tsp->tv_nsec < 0 || 1393 tsp->tv_nsec >= 1000000000) { 1394 error = EINVAL; 1395 goto done_nl; 1396 } 1397 if (timespecisset(tsp)) { 1398 if (tsp->tv_sec <= INT32_MAX) { 1399 rsbt = tstosbt(*tsp); 1400 if (TIMESEL(&asbt, rsbt)) 1401 asbt += tc_tick_sbt; 1402 if (asbt <= INT64_MAX - rsbt) 1403 asbt += rsbt; 1404 else 1405 asbt = 0; 1406 rsbt >>= tc_precexp; 1407 } else 1408 asbt = 0; 1409 } else 1410 asbt = -1; 1411 } else 1412 asbt = 0; 1413 marker = knote_alloc(1); 1414 if (marker == NULL) { 1415 error = ENOMEM; 1416 goto done_nl; 1417 } 1418 marker->kn_status = KN_MARKER; 1419 KQ_LOCK(kq); 1420 1421 retry: 1422 kevp = keva; 1423 if (kq->kq_count == 0) { 1424 if (asbt == -1) { 1425 error = EWOULDBLOCK; 1426 } else { 1427 kq->kq_state |= KQ_SLEEP; 1428 error = msleep_sbt(kq, &kq->kq_lock, PSOCK | PCATCH, 1429 "kqread", asbt, rsbt, C_ABSOLUTE); 1430 } 1431 if (error == 0) 1432 goto retry; 1433 /* don't restart after signals... */ 1434 if (error == ERESTART) 1435 error = EINTR; 1436 else if (error == EWOULDBLOCK) 1437 error = 0; 1438 goto done; 1439 } 1440 1441 TAILQ_INSERT_TAIL(&kq->kq_head, marker, kn_tqe); 1442 influx = 0; 1443 while (count) { 1444 KQ_OWNED(kq); 1445 kn = TAILQ_FIRST(&kq->kq_head); 1446 1447 if ((kn->kn_status == KN_MARKER && kn != marker) || 1448 (kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1449 if (influx) { 1450 influx = 0; 1451 KQ_FLUX_WAKEUP(kq); 1452 } 1453 kq->kq_state |= KQ_FLUXWAIT; 1454 error = msleep(kq, &kq->kq_lock, PSOCK, 1455 "kqflxwt", 0); 1456 continue; 1457 } 1458 1459 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 1460 if ((kn->kn_status & KN_DISABLED) == KN_DISABLED) { 1461 kn->kn_status &= ~KN_QUEUED; 1462 kq->kq_count--; 1463 continue; 1464 } 1465 if (kn == marker) { 1466 KQ_FLUX_WAKEUP(kq); 1467 if (count == maxevents) 1468 goto retry; 1469 goto done; 1470 } 1471 KASSERT((kn->kn_status & KN_INFLUX) == 0, 1472 ("KN_INFLUX set when not suppose to be")); 1473 1474 if ((kn->kn_flags & EV_DROP) == EV_DROP) { 1475 kn->kn_status &= ~KN_QUEUED; 1476 kn->kn_status |= KN_INFLUX; 1477 kq->kq_count--; 1478 KQ_UNLOCK(kq); 1479 /* 1480 * We don't need to lock the list since we've marked 1481 * it _INFLUX. 1482 */ 1483 if (!(kn->kn_status & KN_DETACHED)) 1484 kn->kn_fop->f_detach(kn); 1485 knote_drop(kn, td); 1486 KQ_LOCK(kq); 1487 continue; 1488 } else if ((kn->kn_flags & EV_ONESHOT) == EV_ONESHOT) { 1489 kn->kn_status &= ~KN_QUEUED; 1490 kn->kn_status |= KN_INFLUX; 1491 kq->kq_count--; 1492 KQ_UNLOCK(kq); 1493 /* 1494 * We don't need to lock the list since we've marked 1495 * it _INFLUX. 1496 */ 1497 *kevp = kn->kn_kevent; 1498 if (!(kn->kn_status & KN_DETACHED)) 1499 kn->kn_fop->f_detach(kn); 1500 knote_drop(kn, td); 1501 KQ_LOCK(kq); 1502 kn = NULL; 1503 } else { 1504 kn->kn_status |= KN_INFLUX; 1505 KQ_UNLOCK(kq); 1506 if ((kn->kn_status & KN_KQUEUE) == KN_KQUEUE) 1507 KQ_GLOBAL_LOCK(&kq_global, haskqglobal); 1508 KN_LIST_LOCK(kn); 1509 if (kn->kn_fop->f_event(kn, 0) == 0) { 1510 KQ_LOCK(kq); 1511 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1512 kn->kn_status &= 1513 ~(KN_QUEUED | KN_ACTIVE | KN_INFLUX); 1514 kq->kq_count--; 1515 KN_LIST_UNLOCK(kn); 1516 influx = 1; 1517 continue; 1518 } 1519 touch = (!kn->kn_fop->f_isfd && 1520 kn->kn_fop->f_touch != NULL); 1521 if (touch) 1522 kn->kn_fop->f_touch(kn, kevp, EVENT_PROCESS); 1523 else 1524 *kevp = kn->kn_kevent; 1525 KQ_LOCK(kq); 1526 KQ_GLOBAL_UNLOCK(&kq_global, haskqglobal); 1527 if (kn->kn_flags & (EV_CLEAR | EV_DISPATCH)) { 1528 /* 1529 * Manually clear knotes who weren't 1530 * 'touch'ed. 1531 */ 1532 if (touch == 0 && kn->kn_flags & EV_CLEAR) { 1533 kn->kn_data = 0; 1534 kn->kn_fflags = 0; 1535 } 1536 if (kn->kn_flags & EV_DISPATCH) 1537 kn->kn_status |= KN_DISABLED; 1538 kn->kn_status &= ~(KN_QUEUED | KN_ACTIVE); 1539 kq->kq_count--; 1540 } else 1541 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 1542 1543 kn->kn_status &= ~(KN_INFLUX); 1544 KN_LIST_UNLOCK(kn); 1545 influx = 1; 1546 } 1547 1548 /* we are returning a copy to the user */ 1549 kevp++; 1550 nkev++; 1551 count--; 1552 1553 if (nkev == KQ_NEVENTS) { 1554 influx = 0; 1555 KQ_UNLOCK_FLUX(kq); 1556 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1557 nkev = 0; 1558 kevp = keva; 1559 KQ_LOCK(kq); 1560 if (error) 1561 break; 1562 } 1563 } 1564 TAILQ_REMOVE(&kq->kq_head, marker, kn_tqe); 1565 done: 1566 KQ_OWNED(kq); 1567 KQ_UNLOCK_FLUX(kq); 1568 knote_free(marker); 1569 done_nl: 1570 KQ_NOTOWNED(kq); 1571 if (nkev != 0) 1572 error = k_ops->k_copyout(k_ops->arg, keva, nkev); 1573 td->td_retval[0] = maxevents - count; 1574 return (error); 1575 } 1576 1577 /* 1578 * XXX 1579 * This could be expanded to call kqueue_scan, if desired. 1580 */ 1581 /*ARGSUSED*/ 1582 static int 1583 kqueue_read(struct file *fp, struct uio *uio, struct ucred *active_cred, 1584 int flags, struct thread *td) 1585 { 1586 return (ENXIO); 1587 } 1588 1589 /*ARGSUSED*/ 1590 static int 1591 kqueue_write(struct file *fp, struct uio *uio, struct ucred *active_cred, 1592 int flags, struct thread *td) 1593 { 1594 return (ENXIO); 1595 } 1596 1597 /*ARGSUSED*/ 1598 static int 1599 kqueue_truncate(struct file *fp, off_t length, struct ucred *active_cred, 1600 struct thread *td) 1601 { 1602 1603 return (EINVAL); 1604 } 1605 1606 /*ARGSUSED*/ 1607 static int 1608 kqueue_ioctl(struct file *fp, u_long cmd, void *data, 1609 struct ucred *active_cred, struct thread *td) 1610 { 1611 /* 1612 * Enabling sigio causes two major problems: 1613 * 1) infinite recursion: 1614 * Synopsys: kevent is being used to track signals and have FIOASYNC 1615 * set. On receipt of a signal this will cause a kqueue to recurse 1616 * into itself over and over. Sending the sigio causes the kqueue 1617 * to become ready, which in turn posts sigio again, forever. 1618 * Solution: this can be solved by setting a flag in the kqueue that 1619 * we have a SIGIO in progress. 1620 * 2) locking problems: 1621 * Synopsys: Kqueue is a leaf subsystem, but adding signalling puts 1622 * us above the proc and pgrp locks. 1623 * Solution: Post a signal using an async mechanism, being sure to 1624 * record a generation count in the delivery so that we do not deliver 1625 * a signal to the wrong process. 1626 * 1627 * Note, these two mechanisms are somewhat mutually exclusive! 1628 */ 1629 #if 0 1630 struct kqueue *kq; 1631 1632 kq = fp->f_data; 1633 switch (cmd) { 1634 case FIOASYNC: 1635 if (*(int *)data) { 1636 kq->kq_state |= KQ_ASYNC; 1637 } else { 1638 kq->kq_state &= ~KQ_ASYNC; 1639 } 1640 return (0); 1641 1642 case FIOSETOWN: 1643 return (fsetown(*(int *)data, &kq->kq_sigio)); 1644 1645 case FIOGETOWN: 1646 *(int *)data = fgetown(&kq->kq_sigio); 1647 return (0); 1648 } 1649 #endif 1650 1651 return (ENOTTY); 1652 } 1653 1654 /*ARGSUSED*/ 1655 static int 1656 kqueue_poll(struct file *fp, int events, struct ucred *active_cred, 1657 struct thread *td) 1658 { 1659 struct kqueue *kq; 1660 int revents = 0; 1661 int error; 1662 1663 if ((error = kqueue_acquire(fp, &kq))) 1664 return POLLERR; 1665 1666 KQ_LOCK(kq); 1667 if (events & (POLLIN | POLLRDNORM)) { 1668 if (kq->kq_count) { 1669 revents |= events & (POLLIN | POLLRDNORM); 1670 } else { 1671 selrecord(td, &kq->kq_sel); 1672 if (SEL_WAITING(&kq->kq_sel)) 1673 kq->kq_state |= KQ_SEL; 1674 } 1675 } 1676 kqueue_release(kq, 1); 1677 KQ_UNLOCK(kq); 1678 return (revents); 1679 } 1680 1681 /*ARGSUSED*/ 1682 static int 1683 kqueue_stat(struct file *fp, struct stat *st, struct ucred *active_cred, 1684 struct thread *td) 1685 { 1686 1687 bzero((void *)st, sizeof *st); 1688 /* 1689 * We no longer return kq_count because the unlocked value is useless. 1690 * If you spent all this time getting the count, why not spend your 1691 * syscall better by calling kevent? 1692 * 1693 * XXX - This is needed for libc_r. 1694 */ 1695 st->st_mode = S_IFIFO; 1696 return (0); 1697 } 1698 1699 /*ARGSUSED*/ 1700 static int 1701 kqueue_close(struct file *fp, struct thread *td) 1702 { 1703 struct kqueue *kq = fp->f_data; 1704 struct filedesc *fdp; 1705 struct knote *kn; 1706 int i; 1707 int error; 1708 int filedesc_unlock; 1709 1710 if ((error = kqueue_acquire(fp, &kq))) 1711 return error; 1712 1713 filedesc_unlock = 0; 1714 KQ_LOCK(kq); 1715 1716 KASSERT((kq->kq_state & KQ_CLOSING) != KQ_CLOSING, 1717 ("kqueue already closing")); 1718 kq->kq_state |= KQ_CLOSING; 1719 if (kq->kq_refcnt > 1) 1720 msleep(&kq->kq_refcnt, &kq->kq_lock, PSOCK, "kqclose", 0); 1721 1722 KASSERT(kq->kq_refcnt == 1, ("other refs are out there!")); 1723 fdp = kq->kq_fdp; 1724 1725 KASSERT(knlist_empty(&kq->kq_sel.si_note), 1726 ("kqueue's knlist not empty")); 1727 1728 for (i = 0; i < kq->kq_knlistsize; i++) { 1729 while ((kn = SLIST_FIRST(&kq->kq_knlist[i])) != NULL) { 1730 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1731 kq->kq_state |= KQ_FLUXWAIT; 1732 msleep(kq, &kq->kq_lock, PSOCK, "kqclo1", 0); 1733 continue; 1734 } 1735 kn->kn_status |= KN_INFLUX; 1736 KQ_UNLOCK(kq); 1737 if (!(kn->kn_status & KN_DETACHED)) 1738 kn->kn_fop->f_detach(kn); 1739 knote_drop(kn, td); 1740 KQ_LOCK(kq); 1741 } 1742 } 1743 if (kq->kq_knhashmask != 0) { 1744 for (i = 0; i <= kq->kq_knhashmask; i++) { 1745 while ((kn = SLIST_FIRST(&kq->kq_knhash[i])) != NULL) { 1746 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1747 kq->kq_state |= KQ_FLUXWAIT; 1748 msleep(kq, &kq->kq_lock, PSOCK, 1749 "kqclo2", 0); 1750 continue; 1751 } 1752 kn->kn_status |= KN_INFLUX; 1753 KQ_UNLOCK(kq); 1754 if (!(kn->kn_status & KN_DETACHED)) 1755 kn->kn_fop->f_detach(kn); 1756 knote_drop(kn, td); 1757 KQ_LOCK(kq); 1758 } 1759 } 1760 } 1761 1762 if ((kq->kq_state & KQ_TASKSCHED) == KQ_TASKSCHED) { 1763 kq->kq_state |= KQ_TASKDRAIN; 1764 msleep(&kq->kq_state, &kq->kq_lock, PSOCK, "kqtqdr", 0); 1765 } 1766 1767 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1768 selwakeuppri(&kq->kq_sel, PSOCK); 1769 if (!SEL_WAITING(&kq->kq_sel)) 1770 kq->kq_state &= ~KQ_SEL; 1771 } 1772 1773 KQ_UNLOCK(kq); 1774 1775 /* 1776 * We could be called due to the knote_drop() doing fdrop(), 1777 * called from kqueue_register(). In this case the global 1778 * lock is owned, and filedesc sx is locked before, to not 1779 * take the sleepable lock after non-sleepable. 1780 */ 1781 if (!sx_xlocked(FILEDESC_LOCK(fdp))) { 1782 FILEDESC_XLOCK(fdp); 1783 filedesc_unlock = 1; 1784 } else 1785 filedesc_unlock = 0; 1786 TAILQ_REMOVE(&fdp->fd_kqlist, kq, kq_list); 1787 if (filedesc_unlock) 1788 FILEDESC_XUNLOCK(fdp); 1789 1790 seldrain(&kq->kq_sel); 1791 knlist_destroy(&kq->kq_sel.si_note); 1792 mtx_destroy(&kq->kq_lock); 1793 kq->kq_fdp = NULL; 1794 1795 if (kq->kq_knhash != NULL) 1796 free(kq->kq_knhash, M_KQUEUE); 1797 if (kq->kq_knlist != NULL) 1798 free(kq->kq_knlist, M_KQUEUE); 1799 1800 funsetown(&kq->kq_sigio); 1801 chgkqcnt(kq->kq_cred->cr_ruidinfo, -1, 0); 1802 crfree(kq->kq_cred); 1803 free(kq, M_KQUEUE); 1804 fp->f_data = NULL; 1805 1806 return (0); 1807 } 1808 1809 static void 1810 kqueue_wakeup(struct kqueue *kq) 1811 { 1812 KQ_OWNED(kq); 1813 1814 if ((kq->kq_state & KQ_SLEEP) == KQ_SLEEP) { 1815 kq->kq_state &= ~KQ_SLEEP; 1816 wakeup(kq); 1817 } 1818 if ((kq->kq_state & KQ_SEL) == KQ_SEL) { 1819 selwakeuppri(&kq->kq_sel, PSOCK); 1820 if (!SEL_WAITING(&kq->kq_sel)) 1821 kq->kq_state &= ~KQ_SEL; 1822 } 1823 if (!knlist_empty(&kq->kq_sel.si_note)) 1824 kqueue_schedtask(kq); 1825 if ((kq->kq_state & KQ_ASYNC) == KQ_ASYNC) { 1826 pgsigio(&kq->kq_sigio, SIGIO, 0); 1827 } 1828 } 1829 1830 /* 1831 * Walk down a list of knotes, activating them if their event has triggered. 1832 * 1833 * There is a possibility to optimize in the case of one kq watching another. 1834 * Instead of scheduling a task to wake it up, you could pass enough state 1835 * down the chain to make up the parent kqueue. Make this code functional 1836 * first. 1837 */ 1838 void 1839 knote(struct knlist *list, long hint, int lockflags) 1840 { 1841 struct kqueue *kq; 1842 struct knote *kn; 1843 int error; 1844 1845 if (list == NULL) 1846 return; 1847 1848 KNL_ASSERT_LOCK(list, lockflags & KNF_LISTLOCKED); 1849 1850 if ((lockflags & KNF_LISTLOCKED) == 0) 1851 list->kl_lock(list->kl_lockarg); 1852 1853 /* 1854 * If we unlock the list lock (and set KN_INFLUX), we can eliminate 1855 * the kqueue scheduling, but this will introduce four 1856 * lock/unlock's for each knote to test. If we do, continue to use 1857 * SLIST_FOREACH, SLIST_FOREACH_SAFE is not safe in our case, it is 1858 * only safe if you want to remove the current item, which we are 1859 * not doing. 1860 */ 1861 SLIST_FOREACH(kn, &list->kl_list, kn_selnext) { 1862 kq = kn->kn_kq; 1863 if ((kn->kn_status & KN_INFLUX) != KN_INFLUX) { 1864 KQ_LOCK(kq); 1865 if ((kn->kn_status & KN_INFLUX) == KN_INFLUX) { 1866 KQ_UNLOCK(kq); 1867 } else if ((lockflags & KNF_NOKQLOCK) != 0) { 1868 kn->kn_status |= KN_INFLUX; 1869 KQ_UNLOCK(kq); 1870 error = kn->kn_fop->f_event(kn, hint); 1871 KQ_LOCK(kq); 1872 kn->kn_status &= ~KN_INFLUX; 1873 if (error) 1874 KNOTE_ACTIVATE(kn, 1); 1875 KQ_UNLOCK_FLUX(kq); 1876 } else { 1877 kn->kn_status |= KN_HASKQLOCK; 1878 if (kn->kn_fop->f_event(kn, hint)) 1879 KNOTE_ACTIVATE(kn, 1); 1880 kn->kn_status &= ~KN_HASKQLOCK; 1881 KQ_UNLOCK(kq); 1882 } 1883 } 1884 kq = NULL; 1885 } 1886 if ((lockflags & KNF_LISTLOCKED) == 0) 1887 list->kl_unlock(list->kl_lockarg); 1888 } 1889 1890 /* 1891 * add a knote to a knlist 1892 */ 1893 void 1894 knlist_add(struct knlist *knl, struct knote *kn, int islocked) 1895 { 1896 KNL_ASSERT_LOCK(knl, islocked); 1897 KQ_NOTOWNED(kn->kn_kq); 1898 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == 1899 (KN_INFLUX|KN_DETACHED), ("knote not KN_INFLUX and KN_DETACHED")); 1900 if (!islocked) 1901 knl->kl_lock(knl->kl_lockarg); 1902 SLIST_INSERT_HEAD(&knl->kl_list, kn, kn_selnext); 1903 if (!islocked) 1904 knl->kl_unlock(knl->kl_lockarg); 1905 KQ_LOCK(kn->kn_kq); 1906 kn->kn_knlist = knl; 1907 kn->kn_status &= ~KN_DETACHED; 1908 KQ_UNLOCK(kn->kn_kq); 1909 } 1910 1911 static void 1912 knlist_remove_kq(struct knlist *knl, struct knote *kn, int knlislocked, int kqislocked) 1913 { 1914 KASSERT(!(!!kqislocked && !knlislocked), ("kq locked w/o knl locked")); 1915 KNL_ASSERT_LOCK(knl, knlislocked); 1916 mtx_assert(&kn->kn_kq->kq_lock, kqislocked ? MA_OWNED : MA_NOTOWNED); 1917 if (!kqislocked) 1918 KASSERT((kn->kn_status & (KN_INFLUX|KN_DETACHED)) == KN_INFLUX, 1919 ("knlist_remove called w/o knote being KN_INFLUX or already removed")); 1920 if (!knlislocked) 1921 knl->kl_lock(knl->kl_lockarg); 1922 SLIST_REMOVE(&knl->kl_list, kn, knote, kn_selnext); 1923 kn->kn_knlist = NULL; 1924 if (!knlislocked) 1925 knl->kl_unlock(knl->kl_lockarg); 1926 if (!kqislocked) 1927 KQ_LOCK(kn->kn_kq); 1928 kn->kn_status |= KN_DETACHED; 1929 if (!kqislocked) 1930 KQ_UNLOCK(kn->kn_kq); 1931 } 1932 1933 /* 1934 * remove knote from the specified knlist 1935 */ 1936 void 1937 knlist_remove(struct knlist *knl, struct knote *kn, int islocked) 1938 { 1939 1940 knlist_remove_kq(knl, kn, islocked, 0); 1941 } 1942 1943 /* 1944 * remove knote from the specified knlist while in f_event handler. 1945 */ 1946 void 1947 knlist_remove_inevent(struct knlist *knl, struct knote *kn) 1948 { 1949 1950 knlist_remove_kq(knl, kn, 1, 1951 (kn->kn_status & KN_HASKQLOCK) == KN_HASKQLOCK); 1952 } 1953 1954 int 1955 knlist_empty(struct knlist *knl) 1956 { 1957 1958 KNL_ASSERT_LOCKED(knl); 1959 return SLIST_EMPTY(&knl->kl_list); 1960 } 1961 1962 static struct mtx knlist_lock; 1963 MTX_SYSINIT(knlist_lock, &knlist_lock, "knlist lock for lockless objects", 1964 MTX_DEF); 1965 static void knlist_mtx_lock(void *arg); 1966 static void knlist_mtx_unlock(void *arg); 1967 1968 static void 1969 knlist_mtx_lock(void *arg) 1970 { 1971 1972 mtx_lock((struct mtx *)arg); 1973 } 1974 1975 static void 1976 knlist_mtx_unlock(void *arg) 1977 { 1978 1979 mtx_unlock((struct mtx *)arg); 1980 } 1981 1982 static void 1983 knlist_mtx_assert_locked(void *arg) 1984 { 1985 1986 mtx_assert((struct mtx *)arg, MA_OWNED); 1987 } 1988 1989 static void 1990 knlist_mtx_assert_unlocked(void *arg) 1991 { 1992 1993 mtx_assert((struct mtx *)arg, MA_NOTOWNED); 1994 } 1995 1996 static void 1997 knlist_rw_rlock(void *arg) 1998 { 1999 2000 rw_rlock((struct rwlock *)arg); 2001 } 2002 2003 static void 2004 knlist_rw_runlock(void *arg) 2005 { 2006 2007 rw_runlock((struct rwlock *)arg); 2008 } 2009 2010 static void 2011 knlist_rw_assert_locked(void *arg) 2012 { 2013 2014 rw_assert((struct rwlock *)arg, RA_LOCKED); 2015 } 2016 2017 static void 2018 knlist_rw_assert_unlocked(void *arg) 2019 { 2020 2021 rw_assert((struct rwlock *)arg, RA_UNLOCKED); 2022 } 2023 2024 void 2025 knlist_init(struct knlist *knl, void *lock, void (*kl_lock)(void *), 2026 void (*kl_unlock)(void *), 2027 void (*kl_assert_locked)(void *), void (*kl_assert_unlocked)(void *)) 2028 { 2029 2030 if (lock == NULL) 2031 knl->kl_lockarg = &knlist_lock; 2032 else 2033 knl->kl_lockarg = lock; 2034 2035 if (kl_lock == NULL) 2036 knl->kl_lock = knlist_mtx_lock; 2037 else 2038 knl->kl_lock = kl_lock; 2039 if (kl_unlock == NULL) 2040 knl->kl_unlock = knlist_mtx_unlock; 2041 else 2042 knl->kl_unlock = kl_unlock; 2043 if (kl_assert_locked == NULL) 2044 knl->kl_assert_locked = knlist_mtx_assert_locked; 2045 else 2046 knl->kl_assert_locked = kl_assert_locked; 2047 if (kl_assert_unlocked == NULL) 2048 knl->kl_assert_unlocked = knlist_mtx_assert_unlocked; 2049 else 2050 knl->kl_assert_unlocked = kl_assert_unlocked; 2051 2052 SLIST_INIT(&knl->kl_list); 2053 } 2054 2055 void 2056 knlist_init_mtx(struct knlist *knl, struct mtx *lock) 2057 { 2058 2059 knlist_init(knl, lock, NULL, NULL, NULL, NULL); 2060 } 2061 2062 void 2063 knlist_init_rw_reader(struct knlist *knl, struct rwlock *lock) 2064 { 2065 2066 knlist_init(knl, lock, knlist_rw_rlock, knlist_rw_runlock, 2067 knlist_rw_assert_locked, knlist_rw_assert_unlocked); 2068 } 2069 2070 void 2071 knlist_destroy(struct knlist *knl) 2072 { 2073 2074 #ifdef INVARIANTS 2075 /* 2076 * if we run across this error, we need to find the offending 2077 * driver and have it call knlist_clear or knlist_delete. 2078 */ 2079 if (!SLIST_EMPTY(&knl->kl_list)) 2080 printf("WARNING: destroying knlist w/ knotes on it!\n"); 2081 #endif 2082 2083 knl->kl_lockarg = knl->kl_lock = knl->kl_unlock = NULL; 2084 SLIST_INIT(&knl->kl_list); 2085 } 2086 2087 /* 2088 * Even if we are locked, we may need to drop the lock to allow any influx 2089 * knotes time to "settle". 2090 */ 2091 void 2092 knlist_cleardel(struct knlist *knl, struct thread *td, int islocked, int killkn) 2093 { 2094 struct knote *kn, *kn2; 2095 struct kqueue *kq; 2096 2097 if (islocked) 2098 KNL_ASSERT_LOCKED(knl); 2099 else { 2100 KNL_ASSERT_UNLOCKED(knl); 2101 again: /* need to reacquire lock since we have dropped it */ 2102 knl->kl_lock(knl->kl_lockarg); 2103 } 2104 2105 SLIST_FOREACH_SAFE(kn, &knl->kl_list, kn_selnext, kn2) { 2106 kq = kn->kn_kq; 2107 KQ_LOCK(kq); 2108 if ((kn->kn_status & KN_INFLUX)) { 2109 KQ_UNLOCK(kq); 2110 continue; 2111 } 2112 knlist_remove_kq(knl, kn, 1, 1); 2113 if (killkn) { 2114 kn->kn_status |= KN_INFLUX | KN_DETACHED; 2115 KQ_UNLOCK(kq); 2116 knote_drop(kn, td); 2117 } else { 2118 /* Make sure cleared knotes disappear soon */ 2119 kn->kn_flags |= (EV_EOF | EV_ONESHOT); 2120 KQ_UNLOCK(kq); 2121 } 2122 kq = NULL; 2123 } 2124 2125 if (!SLIST_EMPTY(&knl->kl_list)) { 2126 /* there are still KN_INFLUX remaining */ 2127 kn = SLIST_FIRST(&knl->kl_list); 2128 kq = kn->kn_kq; 2129 KQ_LOCK(kq); 2130 KASSERT(kn->kn_status & KN_INFLUX, 2131 ("knote removed w/o list lock")); 2132 knl->kl_unlock(knl->kl_lockarg); 2133 kq->kq_state |= KQ_FLUXWAIT; 2134 msleep(kq, &kq->kq_lock, PSOCK | PDROP, "kqkclr", 0); 2135 kq = NULL; 2136 goto again; 2137 } 2138 2139 if (islocked) 2140 KNL_ASSERT_LOCKED(knl); 2141 else { 2142 knl->kl_unlock(knl->kl_lockarg); 2143 KNL_ASSERT_UNLOCKED(knl); 2144 } 2145 } 2146 2147 /* 2148 * Remove all knotes referencing a specified fd must be called with FILEDESC 2149 * lock. This prevents a race where a new fd comes along and occupies the 2150 * entry and we attach a knote to the fd. 2151 */ 2152 void 2153 knote_fdclose(struct thread *td, int fd) 2154 { 2155 struct filedesc *fdp = td->td_proc->p_fd; 2156 struct kqueue *kq; 2157 struct knote *kn; 2158 int influx; 2159 2160 FILEDESC_XLOCK_ASSERT(fdp); 2161 2162 /* 2163 * We shouldn't have to worry about new kevents appearing on fd 2164 * since filedesc is locked. 2165 */ 2166 TAILQ_FOREACH(kq, &fdp->fd_kqlist, kq_list) { 2167 KQ_LOCK(kq); 2168 2169 again: 2170 influx = 0; 2171 while (kq->kq_knlistsize > fd && 2172 (kn = SLIST_FIRST(&kq->kq_knlist[fd])) != NULL) { 2173 if (kn->kn_status & KN_INFLUX) { 2174 /* someone else might be waiting on our knote */ 2175 if (influx) 2176 wakeup(kq); 2177 kq->kq_state |= KQ_FLUXWAIT; 2178 msleep(kq, &kq->kq_lock, PSOCK, "kqflxwt", 0); 2179 goto again; 2180 } 2181 kn->kn_status |= KN_INFLUX; 2182 KQ_UNLOCK(kq); 2183 if (!(kn->kn_status & KN_DETACHED)) 2184 kn->kn_fop->f_detach(kn); 2185 knote_drop(kn, td); 2186 influx = 1; 2187 KQ_LOCK(kq); 2188 } 2189 KQ_UNLOCK_FLUX(kq); 2190 } 2191 } 2192 2193 static int 2194 knote_attach(struct knote *kn, struct kqueue *kq) 2195 { 2196 struct klist *list; 2197 2198 KASSERT(kn->kn_status & KN_INFLUX, ("knote not marked INFLUX")); 2199 KQ_OWNED(kq); 2200 2201 if (kn->kn_fop->f_isfd) { 2202 if (kn->kn_id >= kq->kq_knlistsize) 2203 return ENOMEM; 2204 list = &kq->kq_knlist[kn->kn_id]; 2205 } else { 2206 if (kq->kq_knhash == NULL) 2207 return ENOMEM; 2208 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2209 } 2210 2211 SLIST_INSERT_HEAD(list, kn, kn_link); 2212 2213 return 0; 2214 } 2215 2216 /* 2217 * knote must already have been detached using the f_detach method. 2218 * no lock need to be held, it is assumed that the KN_INFLUX flag is set 2219 * to prevent other removal. 2220 */ 2221 static void 2222 knote_drop(struct knote *kn, struct thread *td) 2223 { 2224 struct kqueue *kq; 2225 struct klist *list; 2226 2227 kq = kn->kn_kq; 2228 2229 KQ_NOTOWNED(kq); 2230 KASSERT((kn->kn_status & KN_INFLUX) == KN_INFLUX, 2231 ("knote_drop called without KN_INFLUX set in kn_status")); 2232 2233 KQ_LOCK(kq); 2234 if (kn->kn_fop->f_isfd) 2235 list = &kq->kq_knlist[kn->kn_id]; 2236 else 2237 list = &kq->kq_knhash[KN_HASH(kn->kn_id, kq->kq_knhashmask)]; 2238 2239 if (!SLIST_EMPTY(list)) 2240 SLIST_REMOVE(list, kn, knote, kn_link); 2241 if (kn->kn_status & KN_QUEUED) 2242 knote_dequeue(kn); 2243 KQ_UNLOCK_FLUX(kq); 2244 2245 if (kn->kn_fop->f_isfd) { 2246 fdrop(kn->kn_fp, td); 2247 kn->kn_fp = NULL; 2248 } 2249 kqueue_fo_release(kn->kn_kevent.filter); 2250 kn->kn_fop = NULL; 2251 knote_free(kn); 2252 } 2253 2254 static void 2255 knote_enqueue(struct knote *kn) 2256 { 2257 struct kqueue *kq = kn->kn_kq; 2258 2259 KQ_OWNED(kn->kn_kq); 2260 KASSERT((kn->kn_status & KN_QUEUED) == 0, ("knote already queued")); 2261 2262 TAILQ_INSERT_TAIL(&kq->kq_head, kn, kn_tqe); 2263 kn->kn_status |= KN_QUEUED; 2264 kq->kq_count++; 2265 kqueue_wakeup(kq); 2266 } 2267 2268 static void 2269 knote_dequeue(struct knote *kn) 2270 { 2271 struct kqueue *kq = kn->kn_kq; 2272 2273 KQ_OWNED(kn->kn_kq); 2274 KASSERT(kn->kn_status & KN_QUEUED, ("knote not queued")); 2275 2276 TAILQ_REMOVE(&kq->kq_head, kn, kn_tqe); 2277 kn->kn_status &= ~KN_QUEUED; 2278 kq->kq_count--; 2279 } 2280 2281 static void 2282 knote_init(void) 2283 { 2284 2285 knote_zone = uma_zcreate("KNOTE", sizeof(struct knote), NULL, NULL, 2286 NULL, NULL, UMA_ALIGN_PTR, 0); 2287 } 2288 SYSINIT(knote, SI_SUB_PSEUDO, SI_ORDER_ANY, knote_init, NULL); 2289 2290 static struct knote * 2291 knote_alloc(int waitok) 2292 { 2293 return ((struct knote *)uma_zalloc(knote_zone, 2294 (waitok ? M_WAITOK : M_NOWAIT)|M_ZERO)); 2295 } 2296 2297 static void 2298 knote_free(struct knote *kn) 2299 { 2300 if (kn != NULL) 2301 uma_zfree(knote_zone, kn); 2302 } 2303 2304 /* 2305 * Register the kev w/ the kq specified by fd. 2306 */ 2307 int 2308 kqfd_register(int fd, struct kevent *kev, struct thread *td, int waitok) 2309 { 2310 struct kqueue *kq; 2311 struct file *fp; 2312 cap_rights_t rights; 2313 int error; 2314 2315 error = fget(td, fd, cap_rights_init(&rights, CAP_KQUEUE_CHANGE), &fp); 2316 if (error != 0) 2317 return (error); 2318 if ((error = kqueue_acquire(fp, &kq)) != 0) 2319 goto noacquire; 2320 2321 error = kqueue_register(kq, kev, td, waitok); 2322 2323 kqueue_release(kq, 0); 2324 2325 noacquire: 2326 fdrop(fp, td); 2327 2328 return error; 2329 } 2330